CET A6.1.3 - Construction of DC Motors

The term AC is short for _______ _______.

Alternating Current

Brushes ride on a _______ covering the commutator.

Film

The frame of the motor is a necessary part of the _________ _________.

Isolation ground

The most common DC motor control system is the _______ control system.

Ward-Leonard

During an overhauling condition, the AC motor of the MG becomes a _______.

Brake

DC motors have ______ that distinctly identify them from AC motors.

Brushes

Sparking at the commutator/brush interface is ______________.

An indication of problems.

High power relay contacts that have high inductive loads need ______ _______ devices to reduce damage to the contacts.

Arc quenching

The loop circuit is the high current path between the ________ and the ________.

Generator, motor

Compounding compensates for the _________ of the elevator, providing more or less armature current, particularly during leveling.

Imbalance

Preventing the unwanted buildup of current due to residual magnetism in the loop circuit is the _______ circuit.

Suicide

Series field current produces field flux that is ___________ to the current.

Proportional

The motor field is critical to proper operation and if it opens, the motor will _____.

Rotate uncontrolled.

Brushes must be free in their holders; it is good practice to ______ them on every visit.

Snap

The armature wires are wound into loops whose ends are _______ ______ the commutator.

Soldered to

On a DC moron, the stationary components of the pair of inductors is called the _______.

Commutator

The term DC is short for _______ ________.

Direct Current

Wires in the field poles and armature are wound with ________ wire.

Magnet

MG is short for _________ ________.

Motor generator

The number of poles a DC motor has can be known by counting the number of _________.

brush holders