Level 4 IP Review Flashcards by Wyatt Goulet

What type of wire, when run in free air, can carry the most current?

Bare copper

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What wiring method do you use to wire a motor control center (MCC), the feeders are from the bottom encased in concrete?

PVC with a bond

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Which secondary terminal should be grounded?

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The proper method of cutting the armoured covering off armoured cable is:

b) diagonally across the weave with a hacksaw

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Anti-short bushings are used for protecting conductors in:
a) EMT
b) NMS
c) A/S
d) AC

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The capacitor in a single phase motor does not provide for:
a) correcting the power factor
b) limiting the starting current
c) a leading current in the start winding
d) a lagging current in the run winding

d) a lagging current in the run winding

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A device for measuring the diameter of a motor shaft is:
a) micrometer
b) hydrometer
c) megohmmeter
d) microhmmeter

a) micrometer

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What is used to prevent scaffolding from toppling due to high center of gravity?

Outriggers

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A point in the wiring system where current is taken to supply utilization equipment is called:
a) an outlet
b) a switch box
c) a pull box
d) a junction box

Outlet

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What 3 phase connection can be made using only 2 transformers?

Open Delta

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A fiber optic cable has no signal at the receiving end, what is the likely cause?

Cable is kinked

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The functions of grease in the bearings of an electrical motor is to:

reduce heat from mechanical friction

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To control one light from three different places you would need:

two 3-way and a 4-way

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The holding contacts of a magnetic switch:
a) are in series with the stop buttons
b) are in parallel with the stop button
c) are connected across the holding coil
d) are in series with the start button

a) are in series with the stop buttons

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The combined electrical resistance of a parallel circuit is:
a) less than the resistance of any single device in the circuit
b) equal to the resistance of the largest device in the circuit
c) more than the resistance of any single device in the circuit
d) equal to the resistance of the smallest device in the circuit

a) less than the resistance of any single device in the circuit

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While working at a motor control center, a 208 volt magnetic starter for a 15 horsepower motor is humming louder than the adjacent starters. Which component requires repair?
a) overloads
b) shading coil
c) contactor coil
d) main contacts

b) shading coil

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Service conduit connected to an underground supply system shall be sealed with a suitable
compound to prevent:
a) inductive reactance
b) the entrance of moisture
c) electrolytic action
d) galvanic action

b) the entrance of moisture

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Three way switches may be connected only in:
a) the unfused conductor
b) a three wire system
c) the grounded circuit conductor
d) the ungrounded circuit conductor

d) the ungrounded circuit conductor

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12,460V → 4170V
Autotransformer is connected:
a) Delta-Delta
b) Delta- Wye
c) Wye-Delta
d) Wye-Wye

a) Delta-Delta
because of one open winding

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What is another term for Root Mean Square?
a) Peak value
b) Average value
c) Instantaneous value
d) Effective value

d) Effective value

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What type of single phase motor would best be suited to be used for a domestic refrigerator?
a) Universal
b) Split phase
c) Shaded pole
d) Capacitor start

d) Capacitor start

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An ohmmeter is connected across a discharged capacitor and the needle stabilizes at approximately 100 kΩ. The capacitor is:
a) Leaky
b) Shorted
c) Good
d) None of the above

a) Leaky
Short would read 0

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A shading coil in a magnetic switch is intended to:
a) maintain the switch in closed position
b) reduce arcing
c) reduce chattering
d) make it quicker acting

c) reduce chattering

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An atom that has lost or gained electrons:
a) is negatively charged
b) has a positive charge
c) is said to be ionized
d) becomes electrically neutral

c) is said to be ionized

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In a parallel circuit containing a 4-ohm, and 5-ohm resistor, the current flow is: a) highest through the 4-ohm resistor b) lowest through the 4-ohm resistor c) highest through the 5-ohm resistor d) equal through all the two resistors

a) highest through the 4-ohm resistor less resistance means more current

What two quantities comprise the total power of an AC circuit? a) Apparent power and reactive power b) True power and reactive power c) Apparent power and power factor d) True power and power factor

b) True power and reactive power

A dc generator is a rotating machine that converts: a) electrical energy to mechanical energy b) mechanical energy to electrical energy c) low mechanical energy to a higher level of mechanical energy d) low electrical energy to a higher level of electrical energy

b) mechanical energy to electrical energy

The centrifugal switch in a single phase motor serves the purpose of: a) opening the start winding when the motor has almost reached running speed b) staring the motor when you turn the shaft manually c) allowing the running winding to start after the motor is turning d) acting as a governor after the motor is turning

a) opening the start winding when the motor has almost reached running speed Opens at 75% speed

A safety precaution to follow when using a potential transformer is to: a) ground the secondary b) ground the primary c) insulate the high current d) connect it in series with the line

a) ground the secondary

A carbon resistor color coded red, blue, green, and gold would indicate a tolerance of: a) 2% b) 5% c) 10% d) 20%

b) 5%

The drawings most often used in maintenance work are: a) master electrical drawings and schematics b) schematics and wiring diagrams c) wiring diagrams and isometric drawings d) isometric drawings and schematics

b) schematics and wiring diagrams

The type of diagram that is consulted to find location and interconnection of parts is called a: a) schematic diagram b) master diagram c) wiring diagram d) ladder diagram

c) wiring diagram

The shock factor of electricity is dependent on the amount of: a) resistance b) voltage c) current d) all of the above

d) all of the above

What is the proper way to discharge a capacitor?

Discharge through a resistor then short to ground

What are Scott and T transformer connections

Uses 2 transformers used to transform 3 phase power. One transformer has a midpoint connection called the teaser winding. Teaser winding is rated at 86.6 of line voltage

What are different methods used to cool a transformer?

Air Oil Fan

What type of transformer is not electrically isolated from the load?

Autotransformer

When using instrument transformers for metering purposes, what are the standard secondary ratings of current and voltage used for metering?

120V/5A

Which winding of a step down transformer contains larger wire?

Secondary because of more current

What do polarity dots on a transformer indicate?

Indicates additive or subtractive. Dots are the leads and terminals that have the dots have the same instantaneous polarity

What is the standard direction of rotation for a single phase motor and how is it determined?

NEMA- CCW from opposite end of shaft IEC- CW from shaft

What are the principle reasons for the bearings of a motor to wear out?

No lube/too much belt tension

What is the purpose of the centrifugal switch?

Open the start winding once it reaches 75%

What happens if the centrifugal switch fails to open

Start windings will burn over time

What are the 3 windings associated with split phase motors

Start winding Run winding Squirrel Cage

What is the result if the centrifugal switch is not closed during startup?

Motor will start to hum

The following is stamped on the body of a fuse: "600 V, HRCMISC, 200 A" What does the 200 A stand for?

Amps of continuous current

What is the proper treatment for someone who received severe electric shock?

Keep the victim lying down until competent help is available

Two wire control using, for example, a thermostat is known as:

No-voltage release, low voltage release, under voltage release

Bringing a motor to a quick stop by phase reversal is called:

Plugging

With most general purpose motors, the motor nameplate has an extra load carrying ability known as the motors:

Service factor

Difference between a contractor and a starter is

Starter has overload relays

What time of diagram includes all of the devices in the system and shows their physical relationship to each other

Wiring diagram

What piece of equipment shall be used to prevent the inadvertent interconnection of normal and standby sources of supply?

Transfer switch 46-206(1)

What minimum depth is required when direct burying cathodic protection cables?

450mm 80-002(1)a

A PN junction is a device known as a:

Diode

Rectifier changes: Inverter changes:

Rectifier: AC to DC Inverter: DC to AC

A half wave rectifier produces a:

Pulsating DC

A point in a wiring system that draws current?

An outlet Section 0 - Point of utilization

What is the maximum allowable fusing on a DC motor?

150% of full load current 28-200(3)a

A thermistor is a type of resistor whose resistance is dependent on:

Temperature

How does an open-on-rise thermostat operate?

Temp rises, contacts open, turns off heating system

What is generated when a thermocouple is heated?

Voltage (Flame proving device, senses a flame and translates a message in voltage)

What is the purpose of a push button interlock?

Prevents both starter coils from being energized simultaneously

Prior to opening the switch on the primary of a high voltage distribution transformer, it is good practice to:

Unless the secondary

The type of motor used by the small, motor driven tool industries is the:

Series motor

In universal motors, the armature and field coils are connected in:

Series

The minimum size, single conductor aluminum sheathed or mineral insulated cable allowed in a service is:

#3 AWG 6-304(1)b - Larger than #4

What is the purpose of a heat anticipator on a thermostat?

Anticipate temperature rise

What is the minimum size ground conductor from a high voltage gradient control mat to the ground electrode?

#2/0 AWG 36-310(2)

Polarity should be tested before:

Connecting coils in series or parallel

How does a triac dim an incandescent lamp?

Changing voltage across the lamp

Where do you find number of strands on aluminum sheathed, copper cables?

Table D5

What type of transformer can be used as a motor starter compensator?

An autotransformer

What is the correct action to take if a motor trips out the thermal overloads?

Allow for a cooling period then reset the overloads

Where do you find enclosure types when boxes are exposed to ice?

Table 65

Where do you find conduit sizes for mobile homes?

Section 70 70-104(3) Table 65

What type of AC motor has good variable speed qualities?

Wound rotor

A 3ø, wye connected generator winding has a phase current rating of 10 amps. What is the line current?

10A

The voltage rating of an AC, Wye connected, 3ø generator is 208V. What is the voltage of each winding?

120V

What is a Megger used for?

Insulation resistance

Where do you find specific zones classifications of an aircraft hangar?

Section 20 20-402

A Wye connected generator is rated at 208V and 25. What is the phase rating?

120V - 25A

What is the primary purpose of a 15KV stress cone?

Relieve electrical stress on the cable

What is required to calculate a squirrel cage induction motor's maximum overload rating?

FLA and Service Factor

A thermal relay (like a thermistor) is typically found where?

A motor circuit switch

Where do you find the basic watts/square meter values for buildings?

Table 14

What is the proper angle for setting up an extension ladder?

1' out for every 4' up

While testing insulation resistance with a megger, the response of the pointer is a downward dip followed by a gradual climb to a steady value, what does this indicate?

Good insulation

A split phase, resistance-start motor, and a capacitor-start motor will have:

A different starting torque and the same running torque

How is a centrifugal switch connected in a motor circuit?

In series with the start winding

What type of DC motor would you use when extremely high torque is required, but speed is not important?

Series

What is a proper fire extinguisher for a class C fire, filled with?

CO2

How many terminals are there on a dual terminal supervised, photoelectronic smoke detector?

4 32-106

What is another name for a time delay fuse?

Dual-element

Three wire motor control provides:

Low voltage protection

In what section can you find cathodic protection?

Section 80

What is the most commonly used voltage in a nurse call system?

24V

A 30V control system is classified as:

Extra low voltage circuit

Proper maintenance of control equipment is provided for, by a program of:

Scheduled, periodic maintenance

What are the rectifier percentages?

1/2 - 45% Full - 90% 3ø - 135%

A diode offers low resistance to current in how many directions?

One direction only

A single diode is used to rectify AC voltage. This is known as:

Half-wave rectification

When may an ohmmeter be used in an energized circuit?

Never

A synchronous motor must be started:

As an induction motor

The power factor of a synchronous motor can be varied by changing the:

Field excitation

Short circuited could in a stator are located efficiently by the use of a:

Growler

Class 1 power systems are restricted to what maximum power rating when being supplied by a transformer?

1kVa 16-004

Should a voltmeter be used in series?

The operating relationship of the blower fan in a gas furnace during normal heating operation is:

The fan comes on last and shuts off last

Panelboards installed in a single dwelling shall have how many additional spaces left for future use?

4 8-108(1)

What is meant by "The inverse time characteristics curve" of an overload in a breaker?

A low value of overload will be tolerated much longer than a short circuit

Where can you find the maximum allowable temperature rating of CMR type cable?

Table 19 - Conditions of use

What is the distance a portable extension ladder must extend above the landing when used for access?

900mm or 3'