Variable Frequency Drives (VFD)


Program Scope

This standard applies, within the heating, ventilating, air-conditioning and refrigeration (HVACR) context, to 60 Hz VFDs used in the control of asynchronous induction motors. The range includes all those found within a building including: low voltage (≤ 600 V) and drives that are stand alone, not mechanically integrated into motors.

Variable Frequency Drive

A power electronic device that regulates the speed of an alternating current (AC) motor by adjusting the frequency and the voltage of the electrical power supplied to the motor.

Program Scope Inclusions

This certification program includes only base VFDs which may be incorporated into other configurations, (i.e. bypasses, filters, enclosures) with the following specifications:

  • Designed for use in the control of asynchronous induction motors in HVACR products only designated by the manufacturer;
  • Found within a building that are low voltage (= 600 Volts) and drives that are stand alone; and
  • Custom units – designated to have significantly different system efficiencies harmonic performance or motor stress.

Program Scope Exclusions

This certification program does not include:

  • VFDs mechanically integrated into motors;
  • Brushless DC motor controllers; and
  • Motor Insulation Stress for 208 V VFDs.

Certified Ratings

  • Drive System Efficiency, %
  • Motor Insulation Stress, peak V and rise time, µsec; and
  • Power Line Harmonics, total harmonic current distortion, %

The rules and procedures for obtaining and maintaining certification are detailed in the Resources section above. The specific Standard listed above details the technical requirements for rating and publishing your product performance, the AHRI General Operations Manual (OM) details the program operational rules that are generic to all of AHRI’s certification programs and lastly, the Product-specific Operations Manual provides the operational rules that are specific to this program along with the required documents and fees. Please ensure that you are familiar with the latest rules and procedures for this program.