Industrial Motor Controls

30 V

Any voltage above ____ is considered dangerous

430

Article ____ of the NEC deals with motors and all associated branch circuits

MAN

Manual

MTR

Motor

TD

Time Delay

Starting torque is higher

When a split-phase motor is operated with a capacitor in series with one of the stator windings the ____.

C

use a class- ___ rated fire extinguisher on energized electrical wiring or equipment

the electric connections

what Ladder diagrams show

polyester

what clothing should you avoid wearing on the job?

Limit voltages surges Provide a ground reference that stabilizes Facilitate the operation of over-current devices

what is the purpose of grounding

AC

Alternating current

more

Compared to the high voltage side, the low voltage side of a transformer draws _________ current.

CR

Control Relay

Single-line diagram

What shows an electrical installation reduced to its simplest form

Single-line diagram

Which of the following diagrams shows an electrical installation reduced to its simplest form?

5

With a current imbalance as low as ______ milliamperes, a GFCI will activate and open the circuit

Labeled, Listed

____ or _____ indicates that a piece of electrical equipment or material has been tested and evaluated for the purpose for which it intended to be used

PB

Push Button

REC

Rectifier

10 feet

keep materials and equipment at least ___ feet away from high voltage overhead power lines

tagout

Electrical ____ is the process of placing a danger tag on the source of electrical power, which indicates thath the equipment may not be operated until the danger tag is removes

locking

Electrical lockout refers to the process of ____ the power source in the off position

T1, T2, T3

Three-phase motor terminal connections

Transformer

Trans

Bonding

limits the touch voltage when non-current-carrying metal parts are inadvertently energized

punctures

Leather gloves are worn over rubber gloves to protect from ____

RH

Rheostat

Outlines the minimum requirments that must be met for a safe wiring installation

The National Electrical Code (NEC)

exciting

The __________ current sets up an alternating flux in the core of a transformer.

PB

The abbreviation most commonly used for a pushbutton switch is

Burns

The most common electricity- related injuries are _____

KVA per HP

The motor nameplate Code letter specifies the locked rotor current rating of the motor in

Listed

After vigorous testing to UL standards, the product, if it passes, is then referred to as being __________ by Underwriters' Laboratories.

reducing the value of the applied voltage

An autotransformer motor starter reduces the starting current to the motor by

circuit

An electric shock can result any time a body becomes part of an electric ____

feeder conductors

Conductors that deliver energy from the service equipment to the final branch circuit overcurrent device are known as

1. checked by metering the voltage 2. locked out and tagged out before starting any repairs

Dead circuits should be

Series

In a dual-voltage split-phase motor, the two run winding are connected in ____ for the high-voltage operation

series

In a dual-voltage split-phase motor, the two run windings are connected in ______ for the HIGH voltage operation.

5 A

In the US, the secondary winding of a current transformer is designed to produce a standard current of

PL

Pilot light

1. be sure it is not under load 2. stand clear of the box 3. face away while operating the switch

When operating a disconnect switch

NEMA IEC

Which of the following develops standard frame sizes for motors

SOL

Solenoid

PH

Phase

POS

Positive

with instruments and relays

Potential transformers are used

System Equipment

The two distinc parts of a grounding system are the ____ grounding and the ____ grounding

Any difference in current flow between the live and neutral conductors

A GFCI circuit breaker or receptacle monitors

Ground Fault

A GFCI protects against the most common form of electric shock hazard, the

ground

A ground fault circuit interrupter (GFCI) is a device that senses small currents to _____ and acts quickly shut off the current

Ungrounded

A ground fault is an unintenional connection between an _____ conductor of an electric circuit and metallic enclosures and raceways

wye delta

All three phase motors are wired so that the phases are connected in either ____ or ___ configuration

the metal frame will be live

An exposed live wire makes contact with the metal frame of an ungrounded piece of electrical equipment. As a result

discharged

Capacitors should be ____ before handling them

Greater than

If the current in the neutral wire is ______ the current in the hot conductor, a ground fault condition exists.

208 Volts

If the phase-to-neutral voltage is 120 volts in a Wye transformer system the phase-to-phase voltage would be

from a variable frequency drive

Inverter-duty describes a class of motors that are capable of operation

Centrifugal

The device used to automatically disconnect the starting winding of a single- phase splite-phase motor is called a _____ switch

Rotor Stator

The rotating part of an AC motor is referred to as the ____; the stationary part is called the ____

1. frequency of the electrical power supply 2. number of poles built into the motor

The speed of an AC induction motor depends on the

1. Frequency of the electrical power supply 2. Number of poles built into the motor

The speed of an AC induction motor depends on the _____, and _____

Phase A, Phase B, Phase C

The three distinct windings of a three-phase motor are referred to as

Secondary

The transformer winding coil that delivers power to the load is known as the _________ coil winding.

control circuit and power circuit

The two basic parts of a typical motor circuit are the

Grounding

This is the intentional connection of a current carrying conductors to the earth

wye, delta

Three-phase transformers are normally connected in_________ or _________.

underlined

To differentiate between NO and NC contacts on a ladder diagram, NC contacts are identified as a number which is

turn off the power or separate the victim from the current

When a current is still applied to an unconscious victim of electrocution, your first priority is to

current is lower

When a dual-voltage motor is operated at the HIGHER voltage rating the operating

Operating current is higher

When a dual-voltage motor is operated at the lower voltage rating, the _____

starting torque is higher

When a split-phase motor is operated with a capacitor in series with one of the stator windings the

Frame size

When replacing a motor, selecting the same _______ ensures that the mounting mechanism and hole positions will match

UL

Whic is a recognized testing laboratory

wiring diagram

Which of the following diagrams shows all the physical connections of both internal and external wiring involved in the installation of a piece of electrical equipment?

Parallel

Additional START or ON control devices are wired

Loacation

A wiring diagram is intended to show the actual ___ of all components

FWD

Forward

grounded

when installing new machinery ensure that all metal framework is efficiently and permanently

Equipment grounding conductor Grounded conductor Grounding electrode conductor

which conductors form part of the grounding system?

75%

For a given amount of power delivered, doubling the transmission voltage cuts the electrical loses by _________.

5 miliamperes

Generally, a body current flow of above___ is considered dangerous

GND

Ground

NO

Normally open

OL

Overload Relay

SEC

Secondary

Hazardous

locations include petroleum refineries and gasoline storage and dispensing areas.

BKR

Breaker

Ground fault

A GFCI protectcs against this

10%

NEMA requires that the motor be able to carry their rated horsepower at nameplate voltage plus or minus

the general direction of current paths

On a block diagram, the arrows connecting the blocks indicate

the same numbers

On a ladder diagram, all wires that connect to a common point are assigned

1. not as efficient as 3-phase motors 2. not self-starting 3. constructed mainly in small HP sizes

Single-phase motors are

alphabetic classification (A, B, F, H, etc.)

Standard NEMA motor insulation classes are given by

E/R

the amount of current flowing through a body is equal to

System grounding

the connection of one current- carrying conductors to ground

Bonding

the permanent joining together of all non-current-carrying conductive enclosures

Voltage, Current, Resistance

the three electrical factors involved in an electric shock are _____

Bonding

this establishes a low-resistance path for ground fault current