What is a VFD Control Panel

Posted by Yin Tang 14/11/2014 3 Comment(s)

What is a VFD control panel?

Sometimes your work space is dusty, dirty, wet, humid, corrosive, or hot. In those harsh environments, you cannot just mount your VFD exposed. You need a VFD Control panel – an enclosure that protects the VFD and other electric components.

What is a VFD control panel used for?

  • Keeping  all components in one panel
  • Keeping  dust, dirt, and weather out of electrical parts
  • A complete motor control solution (bypass, harmonic filtering, etc.)

What is typically inside a VFD control panel?

There are many components you can put inside a VFD control panel. Here are some examples of what you might find:

  1. VFD – The main component of the motor control panel. The VFD inside will vary in voltage, horsepower, full load amps (FLA), and other specifications. Sometimes you may find redundant VFDs installed in case of a VFD failure.
  2. Line reactors – 3% or 5% to reduce harmonic distortion
  3. Harmonic filters – a more effective way to reduce harmonic distortion
  4. Circuit breaker – protects the electrical circuit from overload or short circuit
  5. Bypass – keeps the system running even if the VFD fails
  6. PLC – Programmable Logic Controller –  for more advanced operations
  7. Modem – for communication purpose
  8. AC or other cooling units –  keeps the panel at a certain temperature depending on surrounding environment
  9. Soft-starter –  starts motor slowly but without speed control
  10. Surge protector – protects the system from voltage spikes
  11. Multiple motor overloads – an option  for powering  multiple motors off one VFD, typically used on fan walls
  12. Anti-condensation heater (available in NEMA 3R panels) – eliminates the buildup of dew inside the VFD panel
  13. Motor starters – for running motors across the line

To see the inside view of a VFD panel, read our article of “Inside a VFD panel”  (coming soon!)

NEMA ratings

The enclosure of a control panel is rated for different resistance levels. The standard was created by National Electrical Manufactures Association (NEMA). Below are some common enclosure ratings:

  • NEMA 1 – General purpose, for indoor use.
  • NEMA 3R – Weather resistant, for outdoor use.
  • NEMA 4 – Watertight, can be hosed down.
  • NEMA 4X – Watertight, can be hosed down, and is also corrosion resistant.

See the complete list of NEMA ratings here

MDI motor control panels

At VFDs.com, we have over 4,000 variations of motor control panels, manufactured by MDI that will get your job done. MDI currently manufactures 3 series of motor control panels: SV1, FF1, F3R; each has its unique advantages. The differences between SV1, FF1, and F3R are as followed:







Slim 12” wide gray enclosure

Gray enclosure, size varies

White enclosure, outdoor rated, size varies

Up to 40 HP

Up to 800 HP

Up to 800 HP

Natural air ventilation

Filtered forced air ventilation

Filtered forced air ventilation

No filters

Pleated air filters

Washable poly filters

Line reactors available

Line reactors & harmonic filters available

Line reactors & harmonic filters available

Standard dial keypad

Advanced full numeric keypad

Advanced full numeric keypad


Get a closer look at each series:




Call us 800-800-2261 to order your panel, starting at $2800:

Leave a Comment

3 Comment(s)

Krishna kumar soni:
03/01/2017, 06:04:20 AM

please ecsess the circuit diagram of vfd for 50kw moter oprating.

Yin (Admin):
03/01/2017, 09:37:58 AM

Krishna, I am not quite sure what you are asking. Are you asking for a circuit diagram of one of these panels?

vicente juniller:
20/03/2016, 05:05:15 AM

Thanks for sharing this useful information.
regards to all

17/03/2015, 12:47:38 PM, dynamictechnologies.info

Really very informative blog.I appreciate your efforts.Thanks for sharing with us.