Intro to VFDs Quiz

What is a Variable Frequency Drive?

• A Variable Frequency Drive is a type of battery used in electric vehicles.
• 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.
• A Variable Frequency Drive is a software application for managing electric motors.

• A Variable Frequency Drive is a mechanical device that increases the size of electric motors.

What are the 4 components that make up a VFD?

• Rectifier, Filters, IGBTs, Control Unit

• Charger, Filter, Resistor, Display
• Setpoint Generator, Battery, Modulator, Switches

• Transformer, Capacitor, Relay, Amplifier

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

• Pulse Width Modulation (PWM)
• Phase Shift Keying (PSK)
• Amplitude Modulation (AM)
• Frequency Modulation (FM)

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.

• 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.

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

• A brake resistor prevents overheating of the VFD during normal operation.
• A brake resistor or chopper dissipates excess regenerative energy as heat during motor deceleration.
• A brake resistor allows the physical brake to engage at different clamping pressures.

• A brake resistor prevents the motor from exceeding a maximum speed.

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

• The size of the motor itself.
• The frequency of the AC from the VFD.

• The voltage supplied to the motor from the VFD.

• The windings of the motor used.

Which "Fault Response" on an SEW VFD will most quickly stop a motor with NO integrated brake.

• Rapid Stop

• Immediate Stop
• Normal Stop

• Anchor Mode

What is SEW's Diagnostic Recording tool called?

• The Scope

• The Glass Onion

• SEW Detective

• SEW Tracer

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

• The memory usage is unaffected by the sample rate.
• The total memory increases allowing more recording time.

• The memory usage decreases giving you a longer period of recording time

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

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?

• 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.