Top 40 VFD(Variable Frequency Drive) Objective type Questions and Answers

1) VFD stands for what?
 
  A. Very Fine Dog
  B. Variable Air Volume
  C. Variable Frequency Drive
  D. Variable Frequency Motor
Ans: C

2) VAV stands for what?
 
  A. Value After Vortex
  B. Variable Air Volume
  C. Variable Frequency Drive
  D. Value After Value
Ans: B

3) The Vapor Side of a system is the
 
  A. High Side
  B. Low Side
  C. Middle Side
  D. Suction Line
  Ans: B

4) The Liquid Side of a system is the
 
  A. High Side
  B. Low Side
  C. Middle Side
  D. Liquid Line
Ans: A

5) What are 2 ways of controlling valves, dampers, ect. in a commercial building?
 
  A. Pneumatic (Missed)
  B. Low Voltage
  C. Electronically (Missed)
  D. High Voltage
Ans: A, C

6.  Low voltage units are typically designed for use with motors rated to deliver 0.2 kW or 1/4 ________ (hp) up to several megawatts.
A. Fuel oil
B. Shoe size
C. Horsepower
D. ISO/IEC 646
Ans: C

7.  An embedded ________ governs the overall operation of the VFD controller.
A. Reduced instruction set computer
B. Central processing unit
C. 64-bit
D. Microprocessor
Ans: D

8.  As new types of ________ switches have been introduced, these have promptly been applied to inverter circuits at all voltage and current ratings for which suitable devices are available.
A. Condensed matter physics
B. Quantum mechanics
C. Physics
D. Semiconductor
Ans: D

9.  The main microprocessor programming is in ________ that is inaccessible to the VFD user.
A. BIOS
B. Read-only memory
C. Firmware
D. Operating system
Ans: C

10.  Introduced in the 1980s, the ________ (IGBT) became the device used in most VFD inverter circuits in the first decade of the 21st century.
A. Insulated-gate bipolar transistor
B. Bipolar junction transistor
C. Power MOSFET
D. Power semiconductor device
Ans: A


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