TPC 206

Question 1

In DC motors, eddy currents can cause:

Answer 1

Overheated brushes

Question 2

Which of the following cells has the shortest service life?

Answer 2

Lead-acid

Question 3

In the electroplating process, the object to be plated is the:

Answer 3

Cathode

Question 4

A typical motor generator set for charging storage batteries uses a _____ on the equipment to shut off the charger after the correct amount of charging time.

Answer 4

Timer unit

Question 5

Electroplating a piece of metal requires a ______ potential difference between the anode and the cathode and a ______ current.

Answer 5

Low; High

Question 6

A solenoid used for closing a valve or releasing a brake is usually made with a ______ shaped magnet.

Answer 6

C-T

Question 7

When a relay operates, it’s NC contacts:

Answer 7

open and remain open

Question 8

The moveable magnetic arm of a relay is called the:

Answer 8

Armature

Question 9

A major cause of a noisy solenoid is loose:

Answer 9

Laminations

Question 10

To increase the service life of DC relay contacts that carry large inductive loads, a ______ can be connected in parallel with the load.

Answer 10

Diode

Question 11

Which part of a DC generator makes electrical contact between the brushes and the coils of wire in the armature?

Answer 11

Commutator

Question 12

The main parts of a DC generator are the field poles, end plates, brushes, brush rigging, commutator, frame and:

Answer 12

Armature

Question 13

A single coil generator produces:

Answer 13

Pulsating DC

Question 14

Commutation is the process in which the rotating commutator segments make and break contact with stationary:

Answer 14

Brushes

Question 15

Small magnetic poles placed between the main poles found surrounding the armature of a DC motor are called:

Answer 15

Interpoles

Question 16

The field windings in a DC compound motor are connected so that _________ with the armature

Answer 16

One is in parallel and one is in series

Question 17

Another name for potential difference is:

Answer 17

Electromotive force

Question 18

One horsepower is equal to 550 ft-lb per second or:

Answer 18

745.7 calories per second

Question 19

Shunt, series and compound refer to different kinds of:

Answer 19

DC motors

Question 20

Never operate a ______ type DC motor without a load, as it will run at such a high speed that it may destroy itself.

Answer 20

Series

Question 21

Which part of a DC armature is made of copper bars that are insulated from each other?

Answer 21

Commutator

Question 22

A winding that doubles back on itself in a drum armature is called:

Answer 22

A Lap winding

Question 23

Which type of power loss varies with the speed of a DC armature and the volume of iron in the core?

Answer 23

Hysteresis loss

Question 24

A bright spark produced while a DC machine is running indicates an _______ in the armature.

Answer 24

Open circuit

Question 25

The two types of windings used on drum armatures are lap windings and _______ windings.

Answer 25

Wave

Question 26

A disc brake is designated to be mounted on the ______ of a motor.

Answer 26

End bell

Question 27

The moveable part of a relay is called the:

Answer 27

Armature

Question 28

Overload relays are usually of the ______ or ______ type.

Answer 28

Thermal; Magnetic

Question 29

The type of DC relay used the most frequently in industry is the ______ relay type.

Answer 29

Shunt

Question 30

Whenever lockout relays are used in DC circuits, the controller is called a ______ starter.

Answer 30

Current limiting

Question 31

An adjustable voltage motor controller varies the potential difference applied to the motor's:

Answer 31

Armature

Question 32

Controllers are rated by duty as _____ or _____.

Answer 32

Continuous; Intermittent

Question 33

Which overload relay is used only in AC circuits?

Answer 33

Magnetic

Question 34

Changes in ambient temperature will change the tripping characteristics of a thermal overload relay unless the relay is:

Answer 34

Temperature compensated

Question 35

An across-the-line starter consists of electrical devices that connect a _____ directly across the incoming power lines.

Answer 35

Direct-current motor

Question 36

The emission of electrons by heating is called:

Answer 36

Thermionic emission

Question 37

A rectifier changes:

Answer 37

AC to DC

Question 38

The simplest electron tube is the:

Answer 38

Diode

Question 39

Four diodes connected in a diamond shaped circuit can deliver full wave rectification in a _____ rectifier circuit.

Answer 39

Bridge

Question 40

Most automobiles use a _______ generator called an alternator, along with rectifiers, to change and run a car's battery and electrical system.

Answer 40

Three-phase AC

Question 41

The part of an SCR that either allows or prevents the flow of electricity is called the:

Answer 41

Gate

Question 42

In an AC circuit, an SCR conducts during ______ of the cycle.

Answer 42

Either half, but not both halves

Question 43

An SCR in an AC circuit can be turned on earlier in the half-cycle in order to _____ the _____.

Answer 43

Increase; Power to the load

Question 44

In an SCR schematic, G stands for gate and K stands for:

Answer 44

Cathode

Question 45

Pulsing a DC circuit is an effective way to control the amount of ______ delivered to a load.

Answer 45

Power

Question 46

A sudden drop in the potential difference between terminals usually indicates an _____ circuit in the field winding of a DC ______.

Answer 46

Open; Generator

Question 47

Before installing a new field coil in a machine, you should:

Answer 47

Determine the polarity of the new coil

Question 48

All DC motor windings carrying full-load current should be examined occasionally for signs of ______ caused by poor or loose connections.

Answer 48

Overheating

Question 49

If you find a ground in the field circuits of a DC machine, the circuits must be disconnected and ______ separately.

Answer 49

Tested

Question 50

Inspect the commutator risers on a DC armature regularly to determine the condition of the solder that secures the windings to the:

Answer 50

Segments