What is A VFD?
 Variable Frequency DriveA variable frequency drive is a control system for alternating current electric motors. It controls the frequency of the electrical power supplied to the motor which allows for variable rotational speeds. A motor does not necessarily need to run at full speed at all times. Additionally, single-speed starters abruptly start motors at rest to full running load, which places mechanical stress on the motor and requires a large influx of electricity. A Variable Frequency Drive supplies energy to the motor on a need-based basis. VFDs will gradually ramp the motor up to operational speeds, decreasing electrical and mechanical stress on the motor. This greatly extends the life of the motor and driven equipment, reducing maintenance and operating costs. The large energy influx needed to start a motor from standstill to full speed is avoided, eliminating the single highest energy expenditure and contributing to significant energy savings.

VFD Advantages

  • Reduced power and energy – Energy savings 25%~85%
  • Improved power factor – 95%
  • Improved speed control
  • Increase reliability
    – Decreased mechanical impact from soft-start
  • Decreased maintenance costs
    – Increased equipment life
    – No need for throttles/dampers

VFD Best Applications

  • Built-in soft starting
  • All variable torque applications
  • Compressors – Centrifugal
  • Pumps
    – Chilled water
    – Condenser water
    – Building supply
    – Chemical dosing
  • Blowers
  • Fans

Maintaining Your VFD

  • Keep it clean
    – NEMA 1 category (side vents for cooling airflow) are susceptible to dust contamination
    – Spray oil-free and dry air across the heat sink fan
  • Keep it dry
    – Use a NEMA 12 enclosure and thermostatically controlled space heater if you locate it where condensation is likely
  • Keep connections tight.