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VFD Buying Guide

Posted by Paul Rossiter 18/01/2014 74 Comment(s) Variable Frequency Drives,

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74 Comment(s)

08/11/2019, 02:23:12 PM

We have a 30-40 yr old portable recycling plant It has a 40'semi trailer with all switchgear in it with s/o cords running out to all motors What i ran across is this plant has a vibrating feeder feeding a Jaw crusher , so the operator stop/start feeder as needed with is often because jaw is full I think a varible feeder is the right way to do this. this operator stands on a platform by jaw and has a push button control box w/push on/off and emergency kill button for jaw and feeder it runs back to disconnects. the plant is 480volt 3 phrase the feeder I,d like to do VSD IS A 40HP 1750 RPM WEG MOTOR 48 amps WILL BE DEALING WITH 120DEGREE desert heat in the summer. sorry this is so long but i wanted you guys to have picture in your minds please get back to with your thoughts.

Rich C:
20/09/2019, 06:23:46 AM

I am looking to install a 1/2 HP 3 phase motor with a VFD in a lathe using residential household current. Is there any advantage to using 220 v single phase input over 110 v single phase input?

08/08/2019, 11:38:03 PM

OK.. Lots of info.. mostly repetitive (Im a retired commercial electrician with a conventional & radio electronics background).. I am looking to see what a VFD for my needs will cost.. as opposed to just buying a variable speed motor.
I was considering taking my 1/3 to 1/2 HP induction (or synchronous) motor on a pedestal grinder/buffer.. so I can put a special wire wheel on it.. and be able to reduce the speed to about 600.. for "carding" (or buffing). Im not sure what the FLA or SF is on this motor.. its an old M.Wards motor made specifically for a grinder... rated for 3450 I expect. 600 is about 17.4 %. It would be better if the motor can maintain speed when under load... which will be intermittent but not to heavy for the motor size. Oh.. and of course, its only 120vac, single phase.
Im looking for an idea how much such an inverter will cost. I will be looking at just buying a new grinder (heck, I could use another grinder! I use two... plus a separate).
Thank you kindly,
I also have a friend.. asking me if there is any way I can convert a 3 phase chop saw he picked up to run on single phase. Im guessing the chop saw is about 1 HP. Its rated in Kw and I don't remember the details. For this, Id want to take 120vac and produce a 3 phase output... either in 120 or 208 I expect. What would such a unit cost for that? (no variable, just power conversion.
These are just general rough cost ideas..

Mohd Aman:
30/04/2018, 05:21:05 AM

is this possible to run single phase motor with vfd ?? and if possible then please let me know

Raul P. Santoalla:
14/04/2018, 08:29:56 PM

I'm on the process of technical recommendation to our sanitary landfill system operation.the available power in the site is single phase and i need to convert this to 3 phase power since my loads are 3 phase inductive motors.My question is your VFD's output voltage will be balance or unbalance voltage?My motors rating are listed below:

2 - 1hp,3 phase motor
2 - 3hp,3 phase motor
2 - 5hp,3 phase motor
2 - 7.5 hp, 3 phase motor

Another question is what is your recommendation? Do you put individual VFD to each motor?

Gladly to hear from you.


Majid Ali:
27/12/2017, 06:27:13 AM

KW : 5.5 KW
DC input 50 3ph cOUPLED BY EACH 1 PH 49.9v 132amp
AC output is 380-480v 3ph 11A

Its a solar off grid system, the system is getting trip after 3-4 hrs, can you suggest any help may be vfd can do.

Shailendra Gaekwad:
23/12/2017, 07:37:28 PM

We are a engineering company we required vfd for our rolling machine 60hp,2900rpm motor
Machine bending capacity is 70mm X 3500 in width
Suggest best vfd for our application
Waiting for your reply.

13/12/2017, 06:30:07 AM

I'm looking for a vfd for a 7.5 HP motor .240V 3 phase.Motor is connected to a pump for delievring tick liquid aprox. 300 feet long distance.What specs. for a vfd drive you recomend? Thanks in advance

22/12/2017, 01:13:49 PM

Basically 200 volts vfds are expensive compare to 400 Vols vfd 400 volts is 50 percent cost difference u can use the 400 volts vfd by program settings doing several wiring modifications

26/11/2017, 09:29:31 PM

I am looking for a vfd for a single ph.motor.I'm building a belt grinder and need to slow or speed up the belt when needed.I made a mistake and hurried and bought a 120 1hp motor but if I'm not mistaken there isn't a vfd for this motor correct? It was a old tabe saw motor. Can you please point me in the right direction thank you for your time and your help

21/11/2017, 06:47:33 AM

i have a 15kw 20hp 415v motor 3phase that i want to use for for shredding of plastic laminates, what size or rating of the vfd/inverter should i use.

Mark Cojuangco:
08/10/2017, 05:22:44 PM

Hi Craig Hartman,

We would like to use our 200 Hp electric motor (existing) in a 50 Hp application.

Our idea is:
Since the motor is 200Hp 440V, to use a 220V - 50Hp VFD to power it.

Would this work ?

Thanks in advance for your advice.

Mark Cojuangco

02/09/2017, 03:30:57 AM

We have 04 nos Siemens make Champion series motors model ISE0 284-2YBB0-Z (one Serial No 64305749). Could anybody please confirm whether this model is compatible to VFD application?

12/08/2017, 03:42:42 AM

Hi ...
This Ehab Abdul-Galil form Cargill Egypt...
Need a price offer for VFD for Motor..
315 KW
Speed 745 RPM

02/08/2017, 09:11:22 PM

I bought a CNC router table and the inverter manufacturer is no longer in business so I can't get the instructions to program it and from what I've found online they all program differently. The router motor nameplate shows the following info:
(delta) 220-220 v
17-17 amps
7-7 hp kW, S1
.85-.86 pf
17570-21030 rpm
300-360 Hz

Can you tell me which inverter I need for this application?

Thanks, -Jeff

21/07/2017, 12:21:07 AM

I want to have a VFD to run a centrifugal water pump, 7.5 hp, 3 phase, 230V,FLA is about 23A. but the power supply is single phase. Need to install the VFD outdoor. Which product fits? Thanks.

Raul P. Santoalla:
14/04/2018, 04:59:13 AM

Hi David, I have a similar situation with you.I need also vfd single to trhee phase output.Is someone help you regarding this?

Louis Larson:
30/06/2017, 11:33:15 PM

We have a semi trailer that has a Carrier Vector refrigeration unit. It is a hybrid unit that generates 480v,3ph,60hz in high speed mode, 345v, 3ph, 45hz in low speed. I am looking for a VFD that will handle that range of inputs and output/supply 240v 3ph, 60hz to a regenerative air blower (240v, 3ph, 2.5hp, 6.2A, LRA=74A).Starting ramp-up is ok, no need for speed control, 60hz should be just fine. We currently have the blower wired for 480v, but on low speed, air delivery is not enough.
Thanks for your input on this situation.
Louis Larson

25/06/2017, 01:47:41 PM

My problem is, I have a transformer who need 3 phase. All applicans are connected to the transformer.

Connor (Admin):
27/06/2017, 08:46:56 AM


Can you give us a call at 800-800-2261 so we can get some more info on your setup and give you some recommendations?

Mike L:
19/06/2017, 04:51:07 PM

I'm using a 20hp VFD 54amp. 240vac single phase in, 240vac three phase out. To power a 10hp 25 FLA three phase motor. Everything is running good. My question is on the MOTOR OVERLOAD PROTECTION PARAMETER setting. Should this parameter be set at @49% or doubled up at around 98% because of the derating of the drive for proper motor protection?
Using the provided formula from the drive manufacturer it should be @49% but they don't give me a correction factor for a derated application.

Mitchell Waller:
15/06/2017, 08:35:18 PM

Im building a small concrete plant and have limited power , i only have single phase 240 , i need a motor for mixer which needs to be round a 40 or 50hp and one motor for a conveyer belt , i need them both to have varable speed

28/05/2017, 05:10:39 AM

I want to run a 3 phase 230v 2.7 amp Lodestar CM-1 ton chain hoist in my home shop via single phase 240v supply. Which VFD is best for my need. Also are there any VFD's that are best suited for multi purpose applications? IE run 3 phase lathe or drill and also for bench testing/diagnosing power tools?

Connor (Admin):
30/05/2017, 10:57:50 AM

We'd recommend one of our Mitsubishi D720S drives. It has single phase input and 3 phase output. These VFDs can easily be used for various applications (not simultaneously). Just choose a drive that has a higher amp rating than your machine.

Do you know the amps associated with the lathe and drill? Do both of these have an electric motor powering them?

03/06/2017, 03:53:55 AM

Thanks Connor, It makes sense that your firm attempts to guide potential buyers towards specific vfd's based on their specific application. However in my case I want the most universal vfd possible.. used for bench testing a large range of 3 phase shop equipment with a.c. electric motors at as reasonable a cost as possible. A hobby salvager of power tools at auctions etc. who buys tools "as is" wants the ability to bench test these tools prior to re-listing for sale. I mentioned the 3 phase elec. hoists because I have 3 of them in the process of reconditioning. It could be a milling machine or a lathe etc next. I have to say I like the prices I'm seeing in the link you provided and the 5 year warranty. I just not certain about the 3 h.p.

Connor (Admin):
05/06/2017, 02:49:36 PM

You’re very welcome Joe. Allow me to clarify a little bit. Essentially all VFDs are universal. The only few differences are special features, input/output voltage, input/output phase, overload rating, accessories options, and reliability. Beyond that, all VFDs will do the job.
When you have 1-phase input power and three phase machines, there are dedicated VFDs out there for them. But these 1-phase input, 3-phase output VFDs only go up to 3HP no matter which manufacturer you go to. That is why we asked about the horse powers of your machines. Beyond 3HP, you will need to purchase 3-phase input, 3-phase output VFDs for your machines. But since you have 1-phase input power, you will need to derate your VFD – that means if you have a 10 amp lathe, you will need to buy a 20 amp VFD to use it with 1-phase input power. The VFD will act as a phase converter but you must derate the VFD; otherwise, the drive will trip. If you are derating the VFD, you must connect the VFD straight to the motor without any electronics (lights, switches, etc.) in between.
If you have to buy one VFD to control different machines in the future, there is no perfect way to go about it. If you know you will never get a machine over 10HP, then the most logical way is to get one 20HP drive (you are derating by using a VFD twice as big) for your 1-phase input power. Then you can use that for any machines in your shop.
I hope this makes sense. If you need further help or explanation, feel free to reach out to Yin at ytang@emcsolutions.com and he can answer your questions on the phone. Thanks Joe!

13/04/2017, 08:21:10 PM

if I get a 11 Kw VFD to power up my motor of 5.5kw I only have my power supply provide to me for 5.9 kw, i would have to increase this looks like.

Connor (Admin):
26/05/2017, 12:13:51 PM

Power usage is measured in Amps not kW. We don't know how you got the 5.9 number? If the circumstances allowed, we'd recommend hooking up the drive and seeing if it trips, if it does trip then you'd need more power.

Fausto palermo:
13/04/2017, 02:49:06 AM

Dear Sir
My home main power is 220v single phase,

I h e a scuba compressor 3 phase with a 5.5kw motor,
I was thinking maybe to run it with one inverter but I am not sure which one.

What do you raccomand?

Thank you

Yin (Admin):
13/04/2017, 08:59:37 AM


A 5.5kw 230V motor should have an amp rating of 23A. Since you have single phase power, you will need to purchase a three-phase drive to derate it. Meaning you need to get a 11kw VFD (about 15hp). The Mitsubishi E720 series should be a good fit: FR-E720-470SC-NA. Make sure the VFD goes directly to the motor, do not put any devices in between.

Let me know if you have other questions.

Amir Anvari:
30/03/2017, 06:56:56 AM

Fan application
no commissioning or programming neede.
the items must sheep to DUBAI for one of our projects.
thank you in advance

Yin (Admin):
30/03/2017, 10:09:22 AM


Are you able to give us a call? 800-800-2261

29/03/2017, 03:07:17 AM

I am looking for a suitable vfd to use for a 11kw ac single phase alternator (ac motor driven through flywheel) so the rpm of alternator varies.

Please suggest me a suitable vfd and how to use.

Yin (Admin):
29/03/2017, 02:14:09 PM


Is your motor single phase? Can you provide more specifications on your motor (voltage, phase, amps, etc.)?

What is your power supply (voltage and phase)?

Steven Singleton:
27/03/2017, 11:26:59 AM

We test building envelope fenestration products which require us to apply positive or negative pressures to a test chamber we construct unique to each job. We currently use rheostats or slides to control the CFMs. Our testing requires us to test at specific pressures that typically are held for a period of time before increasing incrementally until the highest test pressure is achieved. Ideally we would like to program these pressures into a laptop which would then cycle through the test pressures. Is this possible or what VFD would you recommend to give us the control we seek?

Below is a list of specs for 3 different motors we own:

Small Blower
Marathon Electric:
• Model EVH 56C34F5310F P
• Horsepower – 1 HP
• Full Load Amps (FLA) - 12.4
• Voltage – 115
• RPM – 3450
• Service Factor – 1.15

Medium Blower:
Atlantic Blowers:
• Model ABT-800 / Serial # 1727SL
• Horsepower – 15 HP
• Full Load Amps (FLA) – (Rated Currency) 36.7/19.4A
• Voltage – 230/460
• RPM – 3500
• Service Factor – 1.10

Large Blower:
Twin City Fan & Blower Co.
• Serial # 95-108918-2-1
• Horsepower – 75 HP
• Full Load Amps (FLA) – (amps) 166/83
• Voltage – 230/460
• RPM – 3550
• Service Factor – 1.15

Yin (Admin):
27/03/2017, 11:55:11 AM


We are consulting one of our engineers. Can you provide a contact number to bdt@emcsolutions.com? Chances are we will need more information about your setup. We will reach out to you later today. Thanks.

24/03/2017, 12:16:03 PM

I'm looking for a VFD for an irrigation system. I've got 2 20hp motors. 3 phase 460vlt 48/24amps. Any info would be appreciated. Thank you

Yin (Admin):
24/03/2017, 12:46:15 PM


Can you give us a call at 800-800-2261 so we can get some more info on your setup and give you some recommendations and pricing? Thanks.

12/03/2017, 09:36:05 PM

I need a vfd for: A 10 hP, 3-phase, 480V, 14 FLA conveyor. What would you recommend? Note: This is a 30 year old conveyor.



Yin (Admin):
20/03/2017, 04:26:47 PM

Hi Dave, I believe one of our team members have reached out to you already. If you haven't found what you are looking for, please give us a call again 800-800-2261. Thank you!

05/03/2017, 05:48:07 AM

I have standard residential single phase power trying to run a 3ph 7.5hp planer. The motor states 17amp on 230volt 3450 rpm. What vfd would you recommend? Thank you for your help

Yin (Admin):
20/03/2017, 04:25:25 PM

Hi Nick,

Most likely a Mitsubishi E720 at 7.5HP. Will you please call us at 800-800-2261? Thank you.

27/02/2017, 07:42:24 PM

Please, recommend a suitable VSD/VFD for a 0.5HP, 50Hz, AC single phase motor,RPM 1500-1750

Yin (Admin):
28/02/2017, 08:48:44 AM

Please review the video and instructions we have in this blog post. You will need your incoming voltage and phase, motor voltage and phase, and your type of application to choose a VFD.

30/01/2017, 03:21:59 PM

hi.. i have a blower motor of siemens 3ph 60hz 440-480v 20.5amp the VFD used for this is
hitachi model l300p
KW : 11/15
input 50/60hz 1ph 380-480v 24amp
output is 380-480v 3ph 22A

the problem my drive is now damage can i replace it with

new dive of LS industrial system
modle IS7
KW : 22.9
INPUT 380-480v 3ph, 44amp
OUTPUT 0- input volt, 30 amp


Yin (Admin):
31/01/2017, 05:02:19 PM


I am not completely understanding the data you provided, specifically "OUTPUT 0- input volt, 30 amp"

You can derate a 3 phase VFD to use it on 1 phase power. The VFD amps should be at least twice as big as the motor amps. So if your 3 phase, 20.5 amps blower motor is running on 1 phase power, you should find a 3 phase, 41 amps VFD to run the motor.

Does that make sense?

Yin (Admin):
31/01/2017, 05:03:57 PM


When you use a 3 phase VFD on 1 phase power, you also need to ensure there are no electrical components between the motor and the VFD. Any switches, lights, etc. will need to be placed after the VFD or on a completely different circuit.

03/01/2017, 11:16:29 PM

Dear Sir,

I have a grid with 3phase-400v/50Hz line-to-line voltage; and want to drive some 100 KVA-3phase LV motors with rating of 480v/60Hz. Which kind of specific VFD product, do you suggest for this application?
Another question is that six-pulse VFD can be utilized in this application?

Yin (Admin):
04/01/2017, 10:35:28 AM


Unless it is a special model, all standard VFDs are six pulse. You can use VFDs for your low voltage motors if they are AC electric motors. To determine which VFD, you will need to know the motor amps and what type of machine/application it is.

Jeff Edmonds:
27/12/2016, 02:31:27 AM

I have a vintage 3/4 horse 3 pH motor for a lathe that I need to fit with a vfd.
Please tell me what you need to know about it in order to point t me at a specific product.

I will only be running the motor at full speed controlling speeds mechanically with the lathe controls

Yin (Admin):
27/12/2016, 10:22:43 AM

Hi Jeff,

Please check out the video and the article. You will need to know your input power and your motor specifications. For a lathe, you are most likely looking at a Mitsubishi D700 series VFD.

Single phase power: FRD720S042NA
Three phase power: FRD720042NA

Feel free to call us at 800-800-2261 if you have any questions. Thanks!

Puri Maso:
29/09/2016, 08:05:21 PM

I wantto purchase a couple of vfd ranging of 37kw but I am a bit confused with open vector loop control and what are the advantages?

Yin (Admin):
06/10/2016, 10:23:50 AM


*After talking to our VP of engineering, we have updated this answer. The following response is the most updated answer:

Let me clarify the differences between vector control, open loop, close loop, and standard VFD operation.

Vector control (or field orientated control). Vector control is a feature found in more advanced VFDs. There is open loop vector control and close loop vector control. Open loop means there is no feedback going from the output back to the input. Close loop means that there is feedback going from the output back the input.

Here is an analogy about sending feedback: You are driving the car with cruise control set at 60 km/h and the car starts to go up hill. The car will send a feedback to tell the computer to put in more power in order to maintain the 60 km/h. That is close loop - it sends a feedback from the output to the input. On the other hand, if you are driving the car and just pressing on the gas pedal, that is open loop. You are just giving it a command and it is not giving any feedback from the output to the input.

With a standard drive (non-vector), your speed control is close but it will not be exact. You may get up to 2% variation depending on the motor design. Close loop vector control will get 100% accurate speed, but it needs an encoder. Open loop vector control simulates close loop vector control, it is almost as good and it does not require an encoder. It has gotten better over time to become comparable to close loop vector control. However, if you need any position control, you will need an encoder (close loop), see example below:

Position control can be used in a conveyor in an food processing plant where you need the conveyor belt to stop at specific spots using close loop. First stop, the conveyor belt needs to stop precisely at the first station to fill up each bottle. Then, the conveyor belt moves again and stops precisely at the second station to get the bottle caps put on each bottle. Then, the belt moves again and stops at the third station for packaging. A vector control VFD (with an encoder) has the capability to do that.

I hope this helps!

khalid Ahmad:
29/09/2016, 02:43:12 AM

Hello dears

I want to buy solar VFD for my 3HP submersible pump with 9.8 rated current and 3-phase 230v voltage and the efficiency is 0.79 and the PF is 0.73 in full load. However, one of my friends told that the pump will consume (2.2k / 0.79) = 2.78kw and need (2.78kw/0.73) = 3.8 KVA. Also, he suggested me to get VFD that this load will get 70-80% of its peak power, so he suggested 5.5kw solar VFD. However, I am confused and I think there is some wrong in his calculations!! So, I looked to the ABB solar VFDs and thinking of one of four models for the same 3phase voltage which are:
1- ACS355-03E-13A3-2 which has input(2.2kw,3hp,13.3amp).
2- ACS355-03E-17A6-2 which has input(3kw,4hp,17.6amp).
3- ACS355-03E-24A4-2 which has input(4kw,5hp,24.4amp).
4- ACS355-03E-31A0-2 which has input(5.5kw,7.5hp,31.0amp).

what do you suggest from these and why? and I hope you can tell me the right way for choosing the VFD according to the pump size and power.

Yin (Admin):
05/10/2016, 10:59:44 AM

Hi Khalid,

What do you mean by solar VFD? Are you referring to VFDs that are powered by solar panels?

The ACS355 is a VFD for small machinery. The sizing of your VFD depends on your pump motor. Is the FLA 9.8A? What is your incoming power voltage and phase?

Feel free to email me at ytang@emcsolutions.com and I can further assist you. Thank you!

Yin (Admin):
06/10/2016, 09:53:00 AM

Hi Khalid,

For the convenience of other readers, I am posting your follow up questions here and our response:

(1) Is it right that the pump will consume more than its HP according to the efficiency? he told that my pump will consume (2.2Kw/0.79 = 2.78Kw)!!
(2) Is it right that the pump will consume the KVA depends on the power factor even when we use VFD? he told that my pump will consume (2.78Kw/0.73 = 3.8 KVA)!!
(3) Is it right that we should over size the VFD with 20-30%(so the load will be 70-80%) to increase the drive life? he suggested 5.5kw solar VFD depending on the previous calculations.
(4) If the previous point is wrong, is it right to the regular inverters (the load will not exceed 70-80%)?

This is my situation, and I didn't find an expert to explain to me these things.


Let me try to explain this. Your friend is right about the efficiency. Let’s say if the pump consumes 2 kW, and typical pump motors have a 0.79 efficiency. You can’t use a 2 kW (with a 0.79 efficiency) motor to feed the 2 kW pump. You will need a bigger motor (like a 3 kW) because of the inefficiency of the motor.

But efficiency is only used to size the motor, not the VFD. If you bought a pump that requires a motor, the motor efficiency needs to be taken into consideration to size the motor as we discussed earlier. But if the pump already comes with a motor (many pump manufacturers sell them as a kit), what you need to do is size a VFD based on the motor’s FLA (in this case it is 9.8A as you mentioned). You need a VFD with an equal or higher amp rating.
Mind you that many other factors come into consideration, such as the demand of the application, the ambient temperature, the altitude, etc. The 3HP, 13.3A, ABB ACS355 should be more than sufficient for your 9.8A motor because it is 35% oversized.

And to answer your other question about oversizing and life span, oversizing the VFD will theoretically extend the life of the VFD because the circuitry is designed to withhold more current as the size of the VFD goes up. Think of it like this, if you have a 10HP motor and a 20HP VFD, it is only using 50% of its capability. The VFD is not working very hard, and it won’t be running as hot, hence it will theoretically last longer. However, it is not a guarantee that it will run longer because you have a bigger drive. It is nearly impossible to calculate how much longer it will last because of all the other external factors mentioned earlier. The best thing to do is to keep the VFD cool, dry, and clean. So in conclusion, oversizing will help in most cases but you should not think of it as a guarantee.

I hope this helps!

Paul Mathuson:
25/09/2016, 02:06:30 PM

I have a 3 phase lathe I'm trying to run on single phase supply

The motor is a Brooke crompton
kW 3/2.4
N. 2870/1420
V. 380-420
Hz 50/60

6 terminals.

Yin (Admin):
26/09/2016, 09:55:28 AM


Do you have 230V or 460V from the wall?

02/10/2016, 04:02:14 AM

I have 240v on the wall
I have a photo of the motor name plate but don't seem to be able to attach it to this reply template


Yin (Admin):
05/10/2016, 08:36:04 AM

Hi Paul, can you send it to ytang@emcsolutions.com?

mohamed elkady:
25/09/2016, 02:00:25 AM

Dear sir
I have a machine that has a dc 50 hp dc motor ,2000RPM ,Va 420 volt,Ia 96 A that driven by an electronic module and SCRs.I want to replace this motor by AC one and ac drive what size of ac motor should I choose .

Yin (Admin):
26/09/2016, 09:52:35 AM

Hello Mohamed,

Unless you have a specialty DC motor, for example a stepper DC motor, you can just get another 50HP, 460V AC motor. I would double check the amps is comparable and sufficient for your machine, and then choose a speed (RPM) that you need. If you have a specialty DC motor, you will need to spend more money and time in the selection process. Hope that helps.

14/09/2016, 09:45:54 AM

Dear sir
We have 100 HP moter application is extrusion line.
Just we have repaired it from one shop in turkey.
But still it is showing the error showing DC link voltage not available.
Now turkish engineer saying you can change the connection (input AC) from RYB to RBY.

Last we did the same and it had exploded.

Kindly advice us.

Yin (Admin):
26/09/2016, 09:49:09 AM

Hi Neeraw,

(1) Do you have a DC link choke with your 100HP VFD?
(2) Was it the motor or the VFD that exploded last time?
(3) Have you always had the same VFD running this same application? Or is this a new machine?

You can respond here or email me at ytang@emcsolutions.com


27/08/2016, 01:29:31 PM

I have an rubber extruder machine which runs on DC motor 15HP ,1750/2300 RPM,Armature volts =500 VOLTS, 26.5 Amps, That runs through Emerson VFD drive with 480 volts 3 phase input, I want to change this system to AC motor and drive can you suggest what factor should I consider to replace this system or what size of AC motor and VFD drive would be suitable for this?

29/08/2016, 07:56:23 AM

Hello Bhavesh,

One of our sales associates has contacted you via email. Please send us a picture of your motor and VFD nameplates.

23/08/2016, 01:50:22 AM


(Thus, the rule of thumb for sizing the single phase input on a three-phase drive is to use a VFD rated for 2 times the FLA of the motor. For example if your motor is a 10 HP motor with a FLA of 28 amps, then you would need to select a VFD with an amp rating of 56 amps which ends up being around 20 HP.) can I know standart of that ? NEMA,IEC,IEEE, or others ?


25/08/2016, 08:32:18 AM

A VFD is comprised of a Converter, which converts AC to DC, and an Inverter, which converts the DC back to AC at an adjustable voltage and frequency. The Converter on a 3-phase drive consists of 6 diodes. When using a 3-phase input on a VFD, all 6 diodes are utilized. When you use this drive with a single-phase power supply, only 4 of the diodes are utilized. The rms current goes up by 173% (the square root of 3). However, this is not the whole story. The peak currents can increase even more than this. So, we commonly de-rate the drive by 50% when using a single-phase input on a 3-phase drive. This is a commonly established practice by the manufacturers and is not part of any standard. While this is a rule-of-thumb, you can also check with the manufacturer to see what each particular size VFD is rated for when supplied with a single-phase input. So, your example is correct.
Some very small VFDs are built specifically for 1-phase inputs and 3-phase outputs. These drives do not need to be de-rated since they are supplied from the factory with converters designed for single-phase.

Finally, single-phase systems are typically weaker than 3-phase systems and have lower ability to tolerate power system harmonics. We highly recommend that an ac line reactor or dc link reactor be utilized with the VFD to minimize power system distortion.

09/08/2016, 05:39:30 AM

I'm looking into replacing a 3HP 240v 3Ph Eddy Current drive system with VFD & Vector Duty Motor. The speed requirement is 700-3500 rpm . Is it better to use a motor rated 3500 rpm @ 60hz and slow it down, or a motor rated 900 rpm @60hz and speed it up.


Yin (Admin):
09/08/2016, 08:45:12 AM

Hi Bob,

One of our team members have sent you an e-mail. He can help you with sizing the motor and drive. Thanks!

Rony George:
11/07/2016, 08:50:11 AM

Good day
I wonder if we can ran a 50HP motor with 40 HP VFD!!
What you recomend
Looking forward to your recomendations
Rony George

Yin (Admin):
11/07/2016, 08:54:11 AM

Hi Rony,

It is possible. What is the amps on your motor and VFD?
What is the application?

11/07/2016, 09:04:35 AM

The amps on motor is 45.5Amps
And on VFD is 41Amps

11/07/2016, 09:06:30 AM

The application is wastewater sludge pump

Yin (Admin):
11/07/2016, 11:45:32 AM

Rony, we sent you an email with some info. Let us know if you have more questions!

22/06/2016, 10:39:45 AM

I have single phase power to my building and I need to run 2 machines that run on 3 phase. The main machine is this popsicle freezing machine: http://www.finamac.com/en/produtos/maquinas-de-picoles/robopop-ultra
It uses 220v, 3ph, nom 27a, peak 33a.
The 2nd machine is a cooling tower for it, it uses 220v, 3ph, 2.8a.

What VFD do I need to run these machines?

Thank you!

Yin (Admin):
22/06/2016, 01:16:09 PM

Hey Scott,

I gave you a call and left you a voicemail. Give us a shout, we can help you find the right drives. Thanks Scott.

Toll-free 800-800-2261
Direct line 385-259-6897

mark gudiry:
22/06/2016, 09:57:49 AM

i need a 3hp vfd 120vac 1ph input, and 240vac 3ph output. any suggestions?

mark guidry:
22/06/2016, 10:03:23 AM

0-2000 rpm

Yin (Admin):
22/06/2016, 10:05:21 AM

Hi Mark,

120V VFDs typically go from 1/8HP to 1HP. There are no 3HP 120V 1PH input VFD that I am aware of. However, if you can supply 240V 1PH power, the Mitsubishi D720s series is a great option. Hope that helps.

18/04/2016, 08:15:03 AM

Hi Sir,

I was planning to use 1hp 3phase motor for moving the turret of the capstan lathe and control the motor using VFD. Please advise me on selecting the type of VFD to choose. like variable torque or constant torque( Machining involves vvariable torque )
And i Think 1.5 hp or 2 hp Vfd might be good for my application.
Please do get back on this doubt.

Thank You, :)

21/04/2016, 03:48:24 PM


I hope we were able to answer your questions over email. Let us know if you need more help!

Bhavesh mishra:
05/04/2016, 08:59:50 AM

I have a motor range of 0.37kw to 37kw. 1 VFD will be sufficient for this? Orelse i have to take separate VFD for different range of motors?

05/04/2016, 09:17:32 AM

Hello Bhavesh, we recommend using a VFD for each of your motor. But if you have a VFD for your 37 kW motor, you can use that with your 0.37 kW motor. The VFD needs to be big enough (in amps) for the motor. To find out what size of VFD you need, you have to size the VFD with the full load amps of your motor, as our engineer Craig Hartman has mentioned in the video. We hope this helps!

07/02/2016, 05:12:14 PM

I m building new machine with 2 motor 1 hp and 50 Hp my application is wire saw I am selecting 750 rpm motor and I am running motor only 20 percent less rpm for few hours and go maximum rpm my application need to start with low rpm around 550 then go Max rpm I need constant torque during cutting or say my load on motor depend upon contact of wire saw with stone as wire rope length reduce current drawn by motor reduce but to maintain cutting speed need full power what kind of drive I should go?

Steve Fierst:
14/01/2016, 01:13:58 PM

Is to Toshiba VFD better than an Allen Bradley VFD

Ganesh Shete Patil:
09/01/2016, 09:52:17 AM

Dear sir,
I have all the parameters of motor into my ABB350 series,but the problem is that my motor is of .5HP having 3 phase 415 supply requirment & the maximum voltage I can set into this VFD is only 350 Volt....So I am experiencing a lower speed than stated...so what will the the solution for this..

Ganesh Shete Patil:
11/01/2016, 10:39:33 PM

Sorry Its not 350 volt but its 250 volt

Ganesh Patil:
05/01/2016, 04:23:13 AM

1) I have replaced a old 3 HP two stage water pump with .5 HP motor...my question is can use the old 3 HP VFD to my new 0.5 HP motor...

2) Secondaly how can I calculated FLA for this motor..?

3) The 3 HP VFD that I have is of ABB350 series so is there any setting i have to do to drive this 0.5 HP Motor..?

05/01/2016, 11:02:49 AM

1) Please see Menaria’s comment below regarding an oversized VFD, and let us know if that does not answer your question. As long as the new motor is also rated for the same voltage, then the VFD should work.

2) A motor’s FLA can only be estimated using a number of parameters, such as voltage, horsepower, number of poles, etc. To obtain the actual FLA of the motor, the manufacturer performs a dyno load test.

3) You will have to program the VFD to the new motor. Please give us a call at 1-800-800-2261, and we can connect you with our technical support staff.

27/12/2015, 12:23:39 PM

I have a very old motor and a hoist system. Motor is 3 ph, 208v, 3HP, not inverter-duty rated, and it is linked directly to the hoist. Therefore the motor has constant torque load constantly. I used a Powerflex 525 3HP VFD to drive the motor. The VFD allows heavy-duty operation. The problem I have is that I sometimes have difficulties to start motor run using VFD. However if I just use two fingers to slightly twist motor axial, the motor start run normally. Also a VFD was burned without any error code at this situation. What would be the solution on this problem?
If I am using by-pass mode to drive the motor directly, motor never had problem to start and run normally.
Thanks for your advices.

29/12/2015, 08:36:31 AM

Hi George,

Can you provide us with some more information?
(1) How long have you run the VFD before it was burned?
(2) Is the Powerflex 525 the VFD that is out of commission?
(3) Can you elaborate the problems you are having when you start the motor with the VFD? Does it only start occasionally, or start with strange noise, or something else?

Please e-mail us at bdt@emcsolutions.com and we can continue looking into this issue. Thanks George.

29/12/2015, 08:47:09 PM

1. The burned VFD Unit was new, only used for less than 30 hours when it was burned. We do not have constant use of motor/hoist or VFD. When the VFD was burned, it operated the motor for a few minutes, then started struggling with the load. After a few seconds, without any overloading message, heavy black smoke came from the VFD's power unit.
2. We changed a new VFD, and it is in commission in a stand-alone circuit. We still have weak operation issue with the new VFD. We can feel that the VFD runs the motor weakly in comparison with the bypass mode using regular 3ph power. We observed that the VFD struggles with load, while by-pass runs the motor strongly and regularly.
3. We can use VFD to start motor run with normal load in most of time. But occasionally, and non-reproducibly motor could not start run normally. Whether the VFD runs normally, line current is about 9.6amp. If motor does not start, the current would start to increase and eventually VFD is overloaded. When motor does not start, we can use hand to slightly twist the motor axial, the motor would run normally. Without this slight twist, motor would not run.
4. When motor does not run, I think I could hear very light noise, possibly generated by current through the motor.
5. The VFD is about 7 feet distance from the motor. VFD frequency varies from 20HZ to 60Hz in 3 second. VFD is set to maximum overload values.

Hope the above information would help to understand the problem.
Thank you.

30/12/2015, 11:29:50 AM

Thank you for the detail explanation George, that certainly helped narrowing it down. We have an idea what is happening but it might take a little bit of time to explain the problem and potential solutions. Will you give us a call at 800-800-2261?

Naveen Menaria:
22/12/2015, 01:10:09 AM

Dear sir,
If we apply High rated VFD eg. 60HP VFD on 40Hp Motor then What effect will be on system. please reply

22/12/2015, 04:17:16 PM

A 60HP VFD will operate a 40HP motor without a problem. However, an oversized VFD will generate slightly higher harmonics back onto the line. VFDs are sized by the motor's FLA (full load amps). A 40HP motor may demand a FLA that is higher than the rated amps of a 40HP VFD, thus, a higher horsepower VFD with a higher amps rating is recommended. An oversized VFD will run at a lower temperature and have a longer lifetime. It is important that you program the VFD parameters to the motor nameplate specifications. More importantly, is there a reason you are considering an oversized VFD? There are many reasons a VFD would be oversized (load, environment, temperature, altitude, braking, single-phase input, etc.), and without knowing what those reasons are, we cannot be certain that the VFD is properly sized.

adam gibson:
20/12/2015, 01:18:43 PM

I have machinery, all three phase, 1 to 7.5 hp. I have 240 v single phase and 480 single phase available. Several machines are 480 v only and all machines are currently wired for 480. I will only operate one at a time. I also have a 240/480 three phase transformer. Would I be better off putting output of 240 v VFD through the transformer (I will not change frequency) or looking for a large enough VFD that will accept single phase 440. I have not found one yet.

22/12/2015, 04:41:45 PM

Just to clarify your question, you would like to know if it is more economical to purchase a 240V three-phase VFD and connect the 3-phase output to a 240/480V transformer, or purchase a 480V three-phase input VFD and connect the 3-phase output directly to the motor? The prices of 240V VFDs are only slightly lower, and you may run into some problems when installing a transformer in between the drive and the motor. We recommend that if all of your motors are rated for 480 V, you use a 480V VFD and connect it to your 480V single-phase power supply. You are correct in that your best option is to find a VFD that is large enough (de-rated) to the higher amperage from single phase input. The rule of thumb for single-phase input on a three-phase input VFD is to multiply the motor’s FLA by 2 and find a VFD with a higher amperage rating than that value. For example, if your 7.5HP, 480V motor has an FLA of around 12A, you’ll need to find a drive with an amperage rating greater than or equal to 24A. Please give us a call at 1-800-800-2261 if you would like help finding a VFD for your applications. Also, if you will use one VFD to power all of your motors, read the comment and response above regarding oversized VFDs on smaller motors.

16/12/2015, 12:26:29 PM

I have a 3HP PowerFlex 40 200-240V Single-Phase Input VFD, may I use it for a 1HP , 115V rated sigle phase AC motor?

16/12/2015, 12:31:12 PM

the reason is we only have a 115V power source, however, we have a 3HP PowerFlex 40 200-240V Single-Phase Input VFD at present, do not want to buy an extro one.

17/12/2015, 07:59:24 AM

You’ll need to power the VFD with the voltage and phase it is rated for. If you have single phase power and a single phase motor at 115 V, you’ll need a VFD rated for 115 V single phase input & output. We do not sell single phase input & out drives, but we have heard they exist.

17/12/2015, 01:42:02 PM

Aaron, I wanted to clarify that there are few technologies in single-phase motor speed control, however, they are not popular or cost effective. The most common and reliable solution people go to is converting their single-phase motor to a three-phase motor, and using a VFD to phase make from the single phase input to the three phase motor.

04/12/2015, 06:22:32 AM

I have an older belt-driven lathe with a 1 horsepower, 220 3 phase motor w/2.4 amp rating. I also have an RPC using a 15 horse motor with a knife switch mounted near the lathe. Would like to install a VFD to allow for more spindle speed variability. The motor is older and is not fan-cooled, but I can move the sheave belt to overcome any overheating problem with the motor. Would there be any problem arising from the over-voltage of the third leg that is being generated by the RPC? Would the knife-switch eliminate the possibility of overpowering the VFD upon start-up of the RPC? What size VFD would you recommend? I would say that the torque value would be variable.

Hector M:
27/11/2015, 10:28:12 PM

I have a 10hp 208-230v,3ph,60hz blower motor in a 25ton hvac application that I would like to consider using a vfd, to overcome the noise when it starts and to slow it down on the first stage of cooling and later to ramp it up when it goes into high speed cooling. What would I need to provide you to know how this can be done and about how much?

01/12/2015, 08:27:48 AM


Here is what we would need to know to give you the most competitive price:

What is the FLA of your motor?
What are the properties of your power supply? (also 230V, 3-phase, 60Hz?)
What is the environment like where the vfd will be installed? (dirty/clean, dry/humid, indoor/outdoor, etc.)
What is the elevation of the residing application?
What is the maximum ambient temperature at the site where the VFD will be placed?
What is the lead length (cable length between VFD and motor)?
How will you be controlling the VFD? (i.e. keypad, control room, any communications used)

Paul Lancaster:
19/11/2015, 06:14:10 AM

Can I use a 15 HP VFD on a 10HP motor?

19/11/2015, 08:44:03 AM

Absolutely. The motor’s output power (HP or kW) at a specific voltage (V) dictates how much current (Amps) the motor will need to draw in order to produce that power. If the motor’s Full Load Amps (FLA) - the current it needs to run at full load - does not exceed what the VFD can handle (maximum Amps rating), the VFD will be able to handle the motor’s needs.

Nagendra Yadav:
28/10/2015, 11:57:56 PM

So as I want to start a productive machine of its motor & control supply details are as,
Motor connection details - 30 kw, 3 phase 220 volt in delt / 3 phase 380 volt in star 60 Hz operated with 3 phase 220 volt VFD.
Now the power supply available at our side is 3 phase 380 - 415 volt 50 Hz.So guide me that I could start that machine with our side present power supply or need to change according to machine specification.

Also suggest what is the best option to start the machine.

R.Prabhakar Rao:
22/10/2015, 04:58:22 AM

Please give suitable VFD for RO high pressure pump motor
Motor Kw 37.0, Motor RPM 2950, voltage 450, 3 phase, Full load amps 60.0

Please give suitable VFD specifications.

with regards,
R.Prabhakar Rao

22/10/2015, 02:07:24 PM

A Reverse Osmosis high pressure pump pumping water usually requires a 110% overload – variable torque (VT) – for 1 minute. We have multiple options for a 37kW (50HP), 450V @ 60Hz motor; however, to give you the most competitive price we would need to know a little more on your application.

-What is the environment like? (dirty/clean, dry/humid, indoor/outdoor, etc.)
-What is the elevation of the residing application?
-What is the maximum ambient temperature at the site where the VFD will be placed?
-What is the lead length (cable length between VFD and motor)?
-How will you be controlling the VFD? (i.e. keypad, control room, any communications used)
-Are there any regulations set by the utility company on harmonic pollution?

Feel free to send us an e-mail at bdt@emcsolutions.com

dale race:
12/10/2015, 12:51:28 PM

I have an air compressor that is lightly used. It is presently driven by a 6 wire, 3HP, 3Phase, 1740rpm, 10.6FSA motor. I want to run the motor with a 230V VFD to be switched with the existing pressure switch. The compressor pump has a mechanical unloader.

Could you kindly advise which of your products would best suit the need described?

Thank you for your time and attention,

Dale Race

22/10/2015, 02:29:46 PM

Hi Dale,

Is the motor a WYE-Delta starter?

17/09/2015, 03:22:33 PM


I have a three phase dust collector. 4hp, 3360 rpm, 220 volts, 10.6 amps, 3kw, 60 hz. Can you please advise which vfd I need?


17/09/2015, 04:21:36 PM

Hello Kyle,

Do you have single phase or three phase power?

17/09/2015, 05:28:31 PM

Single phase

18/09/2015, 09:34:30 AM


You should get a 3 phase input, 3 phase output VFD that is twice the size of your 10.6 amps motor. It is called derating when doubling the size of the VFD in order to convert the single phase input power to three phase output. In your case, the closest VFD size would be 7.5HP (typically around 24 amps), such as the Mitsubishi E720 series 7.5HP ($910) new with 5 year warranty. You can also consider the Saftronics C10 series 7.5HP ($561) new surplus with no warranty. We have both in stock. Feel free to give us a call 800-800-2261 or email if you would like more information about them.

The E720 is IP20 rated (there is an opening at the bottom where the wires are connected, IP20 is meant to be mounted inside an enclosure/panel), whereas the C10 series is NEMA 1 rated (it is fully enclosed and can be mounted on the wall by itself).

Hope that helps.

15/09/2015, 08:28:17 AM


I would like to put VFD for two of the motors in the plant, the consumption is 18A and 30A respectively. Its a 3 phase motor which is very old and I don't think its designed for VFD service. In this case which model you recommend?

15/09/2015, 10:04:09 AM

Hi cRK,

We would recommend getting an inverter rated motor if possible. Choosing your VFD will depend on your voltage, application, and how you plan to mount the VFD. If you provide those information, we can give you a couple of suggestions. Thank you.

30/08/2015, 02:25:13 PM

Can I use the VFD for a 2.2kw,2500rpm,6.7amp single phase centrifugal fan? Can I connect it to one of the phases on the output side

01/09/2015, 09:32:36 AM

Hi Chux,

1. We always recommend that you use a 3-phase motor on a Variable Frequency Drive. You cannot use a 3-phase drive to run a 1-phase motor.
2. Single-phase drives do exist, but only work with certain types of single phase motors. We recommend you use a 3-phase motor if possible. If it is not possible, we would need all of the information on the motor nameplate to see if a single-phase VFD would work.

Let us know if you have other questions. Thanks!

24/08/2015, 02:22:45 AM

Can i use a 2 hp drive for my 0.75hp 3 phase motor to get 40rpm motor speed

14/08/2015, 08:32:40 AM

I have a Sid Harvey 1/2 HP single phase, 1725 rpm motor for a furnace distribution blower. I'm looking to reduce the fan speed to quiet the blower and increase the run-time to eliminate short-cycling. I had a Danfoss VLT2800 given to me from a job site, can I use the two together?

Frederick Cox, P.E.:
09/08/2015, 01:39:04 PM

I do not have a hardware-specific comment or request at this time. Rather, I want to congratulate you on your thoughtful and authoritative responses to all inquiries. I was seeking confirmation that an oversize (40HP-rated) VFD drive would work with a 30 HP inverter-rated AC motor; Google led me to your website and I got the answer I needed by browsing your Q and A section. Thank you. You are now on my go-to list for future inquiries and specifications.

24/05/2015, 12:09:33 AM

Is A pump motor rated: 25 Hp, 3-Phase, 230V, 60Hz can be serviced & run by a Single Phase, 230V 60 Hz power supply connected to Variable Torque VFD for motor rated 60Hp? Please advise if this possible prior purchase of VFD unit. Thanks.


13/07/2015, 09:56:00 AM

Hi Miles,

Yes it is possible but with limitations. You need to get a drive that is around 50 HP in order to accept single phase power. More accurately, you should double the amps of the motor instead of the horse power.

You have to connect the VFD to the motor, with nothing in between the two and nothing after the motor. Any lights or switches will have to go before the VFD.

Hope that makes sense. Thanks Miles.

20/04/2015, 03:09:22 PM

Miller Dimension 452 welder, Volts. 230/460/575
3 phase
Amperes. 90/45/36
kW 22.3
60 hertz

Would like to use it at home with available 120/240v Single Phase 60hz.

13/07/2015, 09:45:00 AM


You cannot run a VFD on your welder. Welders typically do not have a motor in them. They are more like a transformer. Also, this one already has a speedometer to control its speed.

VFDs are decided to run motors. One of our engineers said to using a VFD to control a welder is like using a VFD to control lights. It will not work. I hope this helps. Sorry for the slow response.

D Clark:
19/11/2015, 12:58:25 PM

Thank you for your introduction into VFD use here online. I understand that a VFD is not appropriate to run the Miller Dimension 452 Cam was asking about from a single phase supply. However, could the thinking of engineering saying all welders are transformers be slightly limiting?

For example, inverter welders are not transformer based (but also would not work with a VFD)...

But perhaps the older motor-generator welders like the Lincoln-Electric SA-800 that have a 3 phase motor could be controlled by a VFD? perhaps these machines are not easy to purchase anymore in the US but there are still a fair number around and still in use.

Jinn Liong Chin:
30/03/2015, 11:39:47 PM

I have a 803KW motor with voltage 6.6KV and 86A. I have a ABB VSD ACS2000-066-A01K-J4-101, the max output continuous current is 86A. Is it ok to use?

07/04/2015, 10:19:00 AM

Hi Jinn,

Sorry we missed your comment. Theoretically it will work as long as your VFD amp rating is higher than the motor FLA. However, depending on your application, you will likely need a little more headroom. You should consider going at least one size bigger on the VFD.

For example, for applications that are constant torque, you will need 150% to 200% overload. Typically, manufactures will call it the heavy duty rating. For applications that are variable torque, you will need 100% to 120% overload. Typically, manufactures will call it light duty or normal duty rating.

A constant torque rated VFD will have both heavy duty and light duty ratings. You will see something similar to "95/80A" or "95(CT)/80(VT)" in the specifications. You will need to determine if your application is constant torque (heavy duty) or variable torque (light duty), then match your amp rating accordingly. I hope that makes sense.

21/03/2015, 12:46:49 PM

we have an VFD written U1: 3-380V I1-385 Amps U2-3-0-u10-320 Hz.
I2 : 820 amps.

Dooes this mean that the VFD is suitable for withstanidng a current of 385 amps or 820 amps Please advice

23/03/2015, 08:54:00 AM

Hello Balaji,

Can you tell us what brand and model is your VFD?

- Yin

24/02/2015, 04:35:02 AM

can u suggest for us three phase inverter
220V .
+/- 10% voltage
36kw 220 motor
1200 rpm
we need 25~100Hz.
main shaft is pushing biomass briquette
we need to protect inverter from being burned from overload.

25/02/2015, 10:30:00 AM

Hi Naif,

We will send you some suggestions to your e-mail. Thanks!

27/01/2015, 10:06:20 PM

Please suggest me VFD drive or any other for the following two Vacuum PUMP:
1) Model & Spec: ADS-602 By ALCATEL, 3KW, 3-PHASE, 400V, 5.5A.

2)Model & Spec:DUO 65 Double stage, 3-Phase, 400V, 2.2KW, 4A.

Application: Vacuum generation
Please email me the suggested drive model.

Many Thanks and Regard

28/01/2015, 08:06:00 AM


We would be happy to point you in the right direction on your search for the right VFD for your application. I will send you an email shortly with a few additional questions I have for you.



Willy Tom:
14/01/2015, 08:01:43 AM

I have a mixer that serves 2 types of mixes. For example the thin mix will only require low power torque around half or less. The thick mix will require full power torque of the motor. Both mixes will use the same RPM.

Some of the questions I have.

1) Will a VFD work on this application?

2) Will it save and use half of the energy for the thin mix?

3) Can the VFD automatic sense the require preprogrammed require torque automatic adjust to the require torque. Let said if we mixing thin mix, the VFD will automatic use low torque.

4) Can the VDF be preprogrammed to auto sense the require torque for example during initial mix the require torque is very low but the mix will get thicker as more ingredient is added for the thick mix.


21/01/2015, 10:27:00 AM

Yes, a VFD will work for your application and will allow you some control in how fast you would like the mixer to operate at. VFDs often result in energy savings by creating more efficient operations. With applications that require high torque (like mixers) it is hard to see significant energy savings because the demand is still going to be pretty high. You may still be able to see energy savings by using a VFD on your mixer, though, most likely, it will not be half.

The VFD will only use the amount of current needed to mix based on the torque at the motor shaft. The motor develops torque as it starts, as the torque builds the drive sends more current and voltage as needed to maintain any increases in speed. Through parameters that you set in your VFD, you can adjust the speed that the mixer will mix at. We have many different drives available, some of which you can input the torque directly into the drive. If you are looking to maintain a specific level of torque you may want to look into using a drive capable of that, such as our A700 Mitsubishi drive.



19/12/2014, 04:22:04 PM

Have a 7.5hp 3 phase lathe. Trying to run on 240v single phase. What are my options? I don't need full 7.5hp of the lathe (this lathe is oversized for my needs, but got a good deal).

22/12/2014, 10:32:00 AM

Hi Ben,

We still need to use a drive that covers 7.5HP even if your lathe requires less than the maximum horsepower. Let me ask you a questions before providing a suggestion.

(1) Is it a spindle lathe?
(2) Do you have an encoder?
(3) What is the full load amps (FLA) of your motor? You can find that on your motor nameplate.

If you prefer to call us, we are more than happy to help you out! 800-800-2261

23/12/2014, 06:45:45 AM

(1) - Yeah. A 18"x59" metal lathe.
(2) - It's built in 1984. Not sure, but probably not?
(3) - I made a mistake. Looks like the motor is only a 5hp. 14amps.

23/12/2014, 12:29:00 PM


We have just sent you an e-mail. Let us if we can help you further. Thanks!

Romeo Bungay:
29/11/2014, 01:49:00 AM

We have a 10 HP 3phase motors for winching machine, is it OK to use VSD with 3phase,15 HP capacity. Appreciating your favorable feedback. Thank you very much.

01/12/2014, 12:50:00 PM

Yes you can use an over-sized VFD for your application.