EMC Chapter 13 Flashcards
Motors operate on the principle that when a ___-carrying conductor is placed in a magnetic field, a force that tends to move the conductor out of the field is exerted on the conductor.
Current
The electron flow motor rule states that the ___ points in the direction of the electron current flow in the conductor.
Index finger
The intensity of the magnetic field and the amount of current in a conductor are normally changed to increase the ___ on the conductor.
Force
A DC motor consists of ___ windings, an armature, a commutator, and brushes.
Field
A commutator connects each armature winding to the brushes using ___ bars (segments) that are insulated from each other with pieces of mica.
Copper
A spring placed behind the brush forces the brush to make contact with the ___.
Commutator
A commutator rotates in ___* increments.
180
DC motors require more maintenance than AC motors because they have ___ that wear.
Brushes
___ is exerted on an armature when it is positioned so that the plane of the armature loop is parallel to the field, and the armature loop sides are at right angles to the magnetic field.
Torque
A DC series motor is a DC motor that has the series field connected in series with the ___.
Armature
The ___ that is produced by a motor depends on the strength of the magnetic field in the motor.
Torque
A DC ___ motor should always be connected directly to the load and not through belts, chains, etc.
Series
In a DC shunt motor, if the ___ to the armature is reduced, the speed is also reduced.
Voltage
A(n)___ is used to increase or decrease the strength of the field or armature in a DC shunt motor.
Rheostat
The wires extending from the shunt field of a DC shunt motor are marked ___.
F1 and F2
