Across
- 3. The back electromotive force (BEMF) voltage that must be generated across the potential relay’s coil to cause the relay armature to move and open the relay contacts between terminals 1 and 2.
- 6. Unit of current flow.
- 7. The difference in the rated rpm of a motor and the actual operating rpm when under a load.
- 8. A device that receives the AC supplied by the power company and converts it to variable voltage DC using silicon-controlled rectifiers (SCRs) and transistors that can be turned off and back on in microseconds
- 12. Circuit in which the current leads the voltage.
- 13. Cycles per second.
- 14. The switching or transistor section of the variable frequency drive (VFD) that produces an AC voltage at just the right frequency for motor speed control. This section converts the DC voltage back to AC voltage.
- 18. This is the voltage-generating effect of an electric motor’s rotor turning within the motor.
- 21. The rotating or moving component of a motor, including the shaft.
- 22. This is the maximum back electromotive force (BEMF) that the relay’s coil can tolerate “continuously” without overheating and opening circuit.
- 23. The speed at which the variable frequency drive’s power device switches the waveform’s positive and negative halves on and off is referred to as the switch frequency or carrier frequency.
- 24. The minimum back electromotive force (BEMF) that the potential relay coil must experience or its armature will drop out and the contacts between terminals 1 and 2 will close.
- 25. Circuit in which the current lags the voltage.
- 26. The region of a magnet towards which the lines of magnetic induction converge (south pole) or from which the lines of induction diverge (north pole).
- 27. A switch that uses a centrifugal action to disconnect the start windings from the circuit.
- 28. A motor rotor constructed from bars.
- 29. A two wire Alternating Current (AC) power circuit.
- 30. A switching device used with hermetic motors that breaks the circuit to the start capacitor and/or start windings after the motor has reached approximately 75% of its running speed.
Down
- 1. The term used to describe the electrical storage ability of a capacitor.
- 2. An electronic device in a motor circuit that is used to control motor speed for variable-speed motors.
- 4. The amount by which the current leads or lags the voltage.
- 5. A solid-state relay with semiconductors used to stop, start, or modulate power in a circuit.
- 8. A compressor starting devices which are variable resistors that vary their resistance when the surrounding temperature changes.
- 9. The twisting force often applied to the starting power of a motor.
- 10. An alternating current motor where the rotor turns from induced magnetism from the field windings.
- 11. The electrical winding in a motor that draws current during the entire running cycle.
- 15. An electrical device activated by a change in current flow.
- 16. A device that surrounds a rotating shaft and provides a low-friction contact surface to reduce wear from the rotating shaft.
- 17. A motor with run and start windings.
- 19. An electrical storage device used to start motors (start capacitor) and to improve the efficiency of motors (run capacitor).
- 20. Refers to a three wire Alternating Current (AC) power circuits.
- 23. The component in a motor that contains the windings: it does not turn.
- 31. The end structure of an electric motor that normally contains the bearings and lubrication system.