The rotating field of an alternator is obtained by exciting the windings on the rotor with
a) AC power
b) stator current
c) magnetic particles
d) DC power
e) carbon poles
Answer: D
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Power Engineering Chapter 81
- Apparent power is the power
- To transfer the power to or from the rotor of alternators or some AC motors
- Brush gear for DC machines have brushes made from carbon because they:
- Synchronous motors have construction that is identical to
- The yoke that supports the main components of the DC machine is frequently made of
- Shunt wound DC motors are common where speed must remain constant regardless of load such as on
- ______ are used on motors and generators to set up a magnetic field.
- A 6 pole alternator producing 60 Hz power must turn at
- The stator of an alternator is built of ______ mounted in a frame.
- A compound wound DC generator may have three characteristics which are a: 1. decreasing output voltage versus load 2. no amperage requirement 3. constant output voltage 4. supplementary AC requirement 5. rising output voltage versus load
- The field rheostat changes the ______ in a DC generator.
- The commutator of a DC machine is made of copper bars mounted in
- The field rheostat in a DC generator is used to adjust the ______ of the motor.
- When synchronizing an alternator; voltage, phase and frequency must all be the same as well as
- A rheostat or "voltage regulator" of a DC shunt wound generator is used to
- A common use for a DC generator is
- The space around a magnet, through which the imaginary magnetic lines of force are considered to travel, is known as the
- The connection provided on DC motors to supply the armature with power
- The field strength of an alternator may be changed by varying the amplitude of the DC power, supplied to the rotating field by:
- Three factors which control the electromotive force developed by a DC generator are the:
- The three main types of DC generators are the: 1. compound wound 2. parallel wound 3. series wound 4. reverse wound 5. shunt wound
- The magnetic field in a DC machine may be supplied by permanent magnets in small units. Large DC machines use field poles that are essentially
- The armature core of a DC machine is built up of laminations of
- In order to produce the strength of magnetic flux required in larger DC machines