CPM - Certified Plant Mechanic Electrical Systems and Controls Flashcards
6 cards from real CPM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CPM - Certified Plant Mechanic Electrical Systems and Controls flashcards as text
What does VFD stand for in industrial motor control?
Answer: Variable Frequency Drive
A VFD (Variable Frequency Drive) controls motor speed by varying the frequency and voltage supplied to the motor.
Which output parameter does a VFD primarily adjust to control the speed of an AC induction motor?
Answer: Output frequency
Motor speed is proportional to supply frequency; a VFD changes output frequency to achieve the desired RPM.
What does PLC stand for in industrial automation?
Answer: Programmable Logic Controller
A PLC (Programmable Logic Controller) is a ruggedized industrial computer used to automate electromechanical processes.
What is regenerative braking in a VFD drive system?
Answer: Returning kinetic energy back to the power supply during deceleration
During regenerative braking, the motor acts as a generator and the VFD can feed energy back to the supply bus, improving system efficiency.
What is the purpose of the acceleration and deceleration ramp settings in a VFD?
Answer: Control the rate of speed change to protect the motor and mechanical components
Accel/decel ramps define how quickly the VFD changes motor speed, reducing mechanical shock and inrush current on the driven equipment.
In PLC programming, what does a ladder diagram represent?
Answer: Graphical control logic using relay contact and coil symbols
Ladder diagram (LD) is a graphical programming language that represents control logic using horizontal rungs with contact (input) and coil (output) symbols modeled after relay logic.