EA 150 Chapter 4 Review Questions
Stator windings can best be described as___.
a structure of copper or aluminum wire coils
The synchronous speed of a motor is the ____.
speed at which the magnetic field rotates
The synchronous speed of a 60Hz, three-phase induction motor with two poles is ___.
3,600 rpm
Doubling the voltage on a dual-voltage motor____.
halves the full-load current
The type of a three-phase motor is determined by the _____.
rotor
The two most common three-phase motor configurations are ____.
wye and delta
A circuit breaker suitable for use as a motor disconnecting means must have a current rating of at least ____.
115% of the motor full-load current
If a squirrel cage induction motor draws 2A of current at 240V and is connected for use on 480V, the amperage will be ___.
1A
Of the following motors, the one most likely to have 15 or 18 motor leads is the _____.
2,400V three-phase motor
With 240V applied to a total parallel impedance of 5 ohms, the current is ____.
48 A
The total resistance of the stator windings in a three-phase motor, if the windings are connected in parallel and the resistance of each winding is 96 ohms, is ____.
48 ohms
If the stator windings of a dual-voltage motor both have an impedance of 10 ohms and they are connected in parallel, the total impedance is ____.
5 ohms
The most common number of motor leads found on a three-phase Wye-wound motor is ______.
9
The main purpose of motor overload protection is to protect the motor ____.
from damaging overload currents
If two 10 ohm windings are connected in series for operation on 480V, the total impedance is _____.
20 ohms