TPC 209

Question 1

The NEMA 7 enclosure is designed for use:

Answer 1

Where flammable or vapors may be present

Question 2

In the _______ mechanism, the hinges armature pivots to the sealed in position.

Answer 2

Clapper

Question 3

The shading coil reduces which of the following in the armature?

Answer 3

Vibration

Question 4

The _____ voltage is the minimum potential difference that will cause the armature to seat against the pole faces of a relay coil.

Answer 4

Seal in

Question 5

What is NOT the result of the potential difference across the coil being too great?

Answer 5

Reduced magnetic force

Question 6

The end barriers on 600 V terminal blocks are ______ than those on 300 V blocks.

Answer 6

Thicker and higher

Question 7

What type of wiring terminals should be used where vibration poses a threat of breakage?

Answer 7

Insulated

Question 8

A specially coated steel spring is required for connecting ______.

Answer 8

Aluminum-to-aluminum wire

Question 9

A connector with no mark is for:

Answer 9

Copper conductors only

Question 10

When a panel is assembled, a plastic wiring duct may be:

Answer 10

Used to avoid the problems of laced wire

Question 11

When applied to pushbuttons, the terms “standard-duty” and “heavy-duty” apply only to the:

Answer 11

Amount of current the pushbutton contacts can carry

Question 12

A NEMA-type 1B flush-mounted station requires a:

Answer 12

4^11/_16 in. single outlet box

Question 13

NEMA type 7 and 9 push button stations for hazardous locations are suitable for all of the following except:

Answer 13

Corrosive fumes or liquids

Question 14

When only one START-STOP station is used with several emergency STOP buttons at different locations, the STOP stations are wired:

Answer 14

In series

Question 15

Which of the following are designed for only AC use?

Answer 15

Joy stick operator

Question 16

The purpose of the actuator in a precision snapswitch is to:

Answer 16

Transmit force from the outside

Question 17

The temperature that develops inside a switch under operating conditions depends on all of the following EXCEPT the __________ current.

Answer 17

Pulse

Question 18

When a remote-cable actuator is used, the switch is mounted:

Answer 18

Where space permits

Question 19

When a plug-in switch needs replacing, what is replaced?

Answer 19

Only the plug-in portion

Question 20

When should a mercury switch be replaced?

Answer 20

When the mercury strings out or breaks up into pools

Question 21

To change a control circuit from one sequence to another, a ______ is used.

Answer 21

Transfer switch

Question 22

Plugging switches can operate either:

Answer 22

Electromechanically or electromagnetically

Question 23

Which kind of switch is classified according to the kind of liquid or gas being measured?

Answer 23

Mechanical pressure

Question 24

Capillary-tube direct-immersion and thermostat are kinds of ______ switches.

Answer 24

Temperature control

Question 25

Float switches are used for controlling all of the following except:

Answer 25

Temperature-maintaining equipment

Question 26

Typical time-delay relays are normally used in applications that:

Answer 26

Do not often need changes in time settings

Question 27

What type of timer has only two cams?

Answer 27

Percentage

Question 28

In the multiple-circuit timer, each set of timer contacts opens or closes according to:

Answer 28

Its’ cam setting

Question 29

If the counter is to be operated from an AC source, a ______ must be used.

Answer 29

Rectifier

Question 30

A revolution counter is used where a machine cannot be controlled by:

Answer 30

Time

Question 31

An undercurrent relay functions when the current reaches a(n):

Answer 31

Lower limit

Question 32

The voltage-sensing relay requires a:

Answer 32

Temperature-compensating network

Question 33

A three-phase sequence-sensing relay de-energizes when the:

Answer 33

Phase relationship is other than A-B-C

Question 34

What is the maximum voltage for a NEMA class B industrial ac relay?

Answer 34

600 V

Question 35

Combustible dusts are Class ______ hazardous materials.

Answer 35

2

Question 36

All of the following are potential sources of ignition EXCEPT:

Answer 36

Aluminum tools dropped on a steel surface

Question 37

Industrial control equipment located in Class I, Division I areas:

Answer 37

Has all arcing parts immersed under 6 in. of oil

Question 38

In hazardous locations where the conduit enters an enclosure that houses arcing or high-temperature equipment, the seal must be within ______ inches of the enclosure it isolates

Answer 38

18

Question 39

After the proper-speed flip-flop (PSF) circuit has been set on a synchronous-motor control unit, the setting can be cleared by a signal from the:

Answer 39

Pole slip (SPL) circuit

Question 39

Eight automatic sequence-decelerating relays are required in a multi-speed starter having ______ speeds.

Answer 39

8

Question 40

An automatic auto transformer starter for a large inductor motor begins by applying ______ line voltage to the motor

Answer 40

Less than full

Question 41

Part-winding starters are generally used with motors having ______-connected windings

Answer 41

Delta

Question 42

The open-circuit transition Y-delta starter has all except:

Answer 42

A set of resistors

Question 43

The NEMA 12 enclosure
has gaskets on all doors, cover and bottom plates, and around operating:

Answer 43

Mechanisms

Question 44

Tin-plated copper busbars are recommended for use in:

Answer 44

Corrosive environments

Question 45

A location for an MCC needs to be all of the following EXCEPT:

Answer 45

Air conditioned

Question 46

If work is required on the secondary circuits of an MCC CT after they have been energized, the secondaries must be:

Answer 46

Short circuited