Chapter 14 - AC Motors

A dual-voltage, wye connected motor has ___ separate circuits.

four

The ___ of a motor should be grounded, especially if the motor is used in a damp location.

frame

The maximum recommended acceleration time depends on the motor ___ size.

frame

An electrician can observe the even blackening of all motor windings that occurs when a motor has failed due to ___.

overloading

In a 3 phase motor, the leads that are brought out externally are labeled with a(n) ___.

T

A ___ motor has the starting winding and capacitor connected in series at all times.

capacitor-run

The capacitor used in the starting winding gives a ___ motor high starting torque.

capacitor-start

When starting a split-phase motor, both the running windings and the starting windings are ___.

connected in parallel

A motor with a service factor of 1.0 is derated when it operates at altitudes above ___'.

3300

When a split-phase motor reaches approximately ___% of full speed, the centrifugal switch opens, disconnecting the starting winding from the circuit.

75

___ motors that fail are usually replaced.

Shaded-pole

___ the stator pole is the simplest method used to start a 1 phase motor.

Shading

The ___ is the stationary part of an AC motor.

stator

To develop a rotating magnetic field in a 3 phase motor, the ___ must be connected to the proper voltage level.

stator windings

A(n) ___ may be used to determine the winding circuits on an unmarked motor by conncting one test lead to any motor lead and temporarily connecting the other test lead to each remaining motor lead.

continuity tester

All capacitors are made with two conducting surfaces separated by ___.

dielectric material

When a motor is first connected to power, the ___ of the starting winding is lower and the resistance is higher than the running winding.

reactance

Some ___ motors include a thermal switch that automatically turns the motor off when it overheats.

split-phase