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