Armature
The DC current of a motor is connected to the field and ___ to produce rotation.
Interpoles
____ are auxiliary poles placed between the main field poles of the motor.
rectifer
An ___ is a device that converts AC to DC by allowing the current to move in one direction.
pigtail
An ___ is an extended, flexible connection
high
The DC permanent-magnet motor produces relatively __- torque at low speeds.
compensated
An __ universal motor is a universal motor with extra winding added to the field poles.
eddy
___ current is unwanted current induced in the metal field structure of a motor, due to the rate of change in the induced magnetic flux.
thyristor
An __ is a solid-state switching device that switches current on by a quick pulse of control current.
armature
An _____ is the rotating part of a DC motor
rotor
An ___ is the rotating part of an AC motor
brushes
An ____ is the stationary part of the DC motor
stator
An ____ is the stationary part of the AC motor
Hysteresis
_____ is the power loss that occurs when a universal motor is connected to AC.
magnetic field
The field windings of a DC motor are used to develop an ____
tapped
An ____ field may be used to vary the speed of a universal motor.
graphite
brushes are made of carbon or ____.
permanent magnet
The DC _____ motor uses magnets for the field winding.
1/4
Compensated universal motors are usually ____ HP and larger
conduction
An SCR can be triggered into ___ in only one direction
laminations
The armature core is made up of notched ___ which form slots when stacked.
high
DC motors are used in applications that require very ___ torque
Brushes
___wear faster than any other component of the DC motor
1/8
The brush holder of DC motor should be 1/16" to ____ from the commutator.
brown
Any discolorations on a commutator other than a polished, ____ color indicate a problem.
True
A universal motor can be operated on either DC or 1 phase, AC.
True
Universal motors may be nonreversible or reversible
false
a revolving field is produced in a universal motor
false
The no-load speed of a universal motor is very low
true
a fixed resistor has a fixed value for one set speed
false
a triac is triggered by a large current to its gate
true
the field pole strength of a universal motor may be changed by moving the brushes
false
AC motors perform better than DC motors in most traction equipment
true
DC power is delivered into the armature through the brushes
true
The brushes of DC motors should be replaced when they have worn down to half their original size
false
The brushes of a DC motor should be lubricated on a scheduled basis
True
a commutator should be smooth and concentric
false
An armature winding is grounded whenever one or more windings make contact with the iron core.
parallel
The field of a DC shunt motor is connected in ____ with the armature
decreases
When a load is placed on a universal motor, the motor speed ____
intensity of the magnetic field
The amount of force exerted on the shaft of a DC motor is based on the ___-
to reduce sparking at the brushes
Interpoles are used ____
produces the heist torque of all DC motors
The DC series motor ____
a series field and a shunt field
The DC compound motor has ___.
has extra windings added to the field poles
A compensated universal motor ____.
anode, gate, and cathode
The three terminals of a SCR are the ___
reversing the direction of current in the field
A reversible universal motor may be reversed by ___.
rotating
The armature is the ___ part of a DC motor.
1/16" to 1/8
When troubleshooting DC motor brushes, the brush holder should be ___from the commutator
5
The brush pressure of a DC motor should be approximately 1.5 to ____ psi of surface area.
1/32" to 1/16
Mica insulation should be approximately ___ below the commutator segments.