Intro to VFDs Flashcard

Front

What is a Variable Frequency Drive?

Back

A Variable Frequency Drive is a device that controls the speed and torque of an electric motor by varying the frequency and voltage of the power supplied.

Front

What are the 4 components that make up a VFD? Options: Rectifier, Filters, IGBTs, Control Unit, Charger, Filter, Resistor, Display, Setpoint Generator, Battery, Modulator, Switches, Transformer, Capacitor, Relay, Amplifier

Back

Rectifier, Filters, IGBTs, Control Unit

Front

What is the process called that a VFD uses to create synthetic AC?

Back

Pulse Width Modulation (PWM)

Front

You have a VFD that is constantly running hot. Assuming your motor is running very quietly in an area where noise is NOT a concern, what could you change to help the drive run cooler? Options: Change the PWM frequency to a lower Hz value., Use a smaller VFD model, Increase the load on the motor, Add an additional VFD to the motor.

Back

Change the PWM frequency to a lower Hz value.

Front

What does a brake resistor or chopper do when used in conjunction with a VFD?

Back

A brake resistor or chopper dissipates excess regenerative energy as heat during motor deceleration.

Front

When utilizing a VFD to control a motor, what sets the speed of the motor?

Back

The frequency of the AC from the VFD.

Front

Which "Fault Response" on an SEW VFD will most quickly stop a motor with NO integrated brake? Options: Rapid Stop, Immediate Stop, Normal Stop, Anchor Mode

Back

Rapid Stop

Front

What is SEW's Diagnostic Recording tool called?

Back

The Scope

Front

What happens to the memory of the scope tool if you increase the sample rate?

Back

The memory usage increases giving you a shorter period of recording time.

Front

If there was an issue with a conveyor motor starting then continuing its motion erratically, what would be the BEST way to set the scope up to try and find the issue? Options: 80% pre-trigger and 20% post-trigger, 10% pre-trigger and 90% post-trigger, 50% pre-trigger and 50% trigger, 60% pre-trigger, 20% trigger and 20% post trigger.

Back

10% pre-trigger and 90% post-trigger.