Quiz
ER-2031 block review
Questions in this quiz (52)
1What is the maximum number of trip coils required for a three phase motor?
- A2
- B3
- C5
- DNot required
2What type of three phase motor has the ability to correct its own power factor and the power factor of other devices connected to the same line?
- AResistance-start induction-run
- BSquirrel-cage induction
- CSynchronous
- DWound-rotor induction
3What is the maximum time-delay fuse that can be used with a three-phase motor of the full load current?
- A125%
- B175%
- C225%
- D300%
4How can locked rotor current be described?
- AIt is the current that wound rotor motor reaches at synchronous speed
- BIt’s the full load current of a squirrel cage motor
- CIt’s the stall current of a three-phase motor
- DIt’s the starting current of a squirrel cage motor
5The over current device will not permit a motor to start. What is the maximum time-delay fuse that can be used with a three-phase motor of the full load current?
- A125%
- B225%
- C300%
- D400%
6What is the basic principle of operation for all three-phase motors?
- AA rotating magnetic field
- BDC field operation
- CBrushless field excitation
- DMaintenance
7A wound rotor motor has a strong starting torque and maintains a smooth acceleration from start to full speed. What percent of full load torque is usually produced?
- A50-100 percent
- B100-200 percent
- C200-300 percent
- D300-400 percent
8What is the phase voltage of a three-phase 600 volt squirrel cage connected delta?
- A208V
- B347V
- C600V
- D750 V
9What does the service factor reveal about the motor?
- AThe length of time the motor may be operated before resting
- BThe expected life of a motor
- CHow often the motor should be serviced
- DHow much of the motor can be continuously loaded without damaging it
10What is the conduction called if one phase of a three-phase motor opens?
- ADouble phasing
- BSingle phasing
- CTriple phasing
- DFree running
11When installing an electrical motor that is totally enclosed, non-vented, with class F insulation rating, the conductors supplying it needs to be rated for what temperature?
- A75C
- B90C
- C110C
- D125C
12A nine lead motor may be connected in wye or delta internally. If this connection is been tested by checking T7, T8, T9 what is it been tested for?
- ALugs
- BPolarity
- CContinuity
- DRotation
13What is the temperature rating of the conductors supplying a motor with a class H insulation rating?
- A90C
- B100C
- C110C
- D120C
14What is the maximum feeder conductor ampacity required to supply a bank of three phase motor are: 96 A, 27A, and 156A
- A279A
- B318A
- C337A
- D303A
15What size of R90 copper conductor is used in a feeder conduit to supply three motors having a full load current of 100amps, 20 amps, and 10 amps? 75 degree rated
- A#1/0 AWG
- B#1 AWG
- C#400mcm
- D#2/0 AWG
16What is the speed at 60 Hz of a 12 pole synchronous motor?
- A120 rpm
- B300rpm
- C600 rpm
- D1200rpm
17In a wound rotor motor, the torque characteristic can be altered by?
- AAdding or removing external resistance
- BAdding and removing external inductance
- CAdding or removing external capacitance
- DTorque may not be altered
18Three-phase motor windings are installed ____ electrical degrees apart from each other
- A90
- B120
- C180
- D270
19What is the term used to describe the amount of torque required to pull the rotor into synchronous speed?
- ACut-out torque
- BCut-in torque
- CPull-out torque
- DPull-in torque
20What is the term used to describe the angle between the centre of the stator pole and the centre is the rotor pole?
- ATorque angle
- BAngle of incidence
- CPhasing angle
- DSynchronous angle
21What is the advantage of a synchronous motor?
- AConstant speed from no load to full load
- BLower voltage starting
- CCan run on either AC and DC
- DSpeed can be controlled
22What size time-delay fuse is required for a three phase, 25hp, 600v, scim
- A20 A
- B30A
- C15A
- D40A
23What meter is used to check phasing in a 3-phase motor when it is de-energized and out of service?
- AClamp-on meter
- BMultimeter
- CPhase rotation meter
- DPhase sequence meter
24What powers the field generation in a typical synchronous motor?
- AExternal resistor
- BExternal DC source
- CExternal AC source
- DExternal capacitors
25The basic principle of all 3 phase motors for synchronous motor is?
- AReluctance
- BCapacitance
- CInduction
- DRotation
26By checking leads T7, T8, T9 of a nine lead motor, an electrician can determine
- AThe voltage of the motor
- BThe FLA of the motor
- CThe winding connection (wye or delta)
- DThe service factor of the motor
27What are synchronous motor mainly used for
- AFan
- BPumps
- CCompressors
- DAll of the above
28The insulation class rating of a totally enclosed non-ventilated motor operating at 90 degrees is
- AType A
- BType F
- CType B
- DType H
29In dual voltage 3 phase motors, the leads are connected in ____ for low voltage and in ____ for high voltage
- AParallel-series
- BSeries-parallel
- CDelta-wye
- DWye-delta
30To find the size of fuse holders that accommodates fuses supplying a group of motors, you must take ____ off the largest motor current and add to this valve of the full load currents of all other motors in a group that may be in operation at the same time.
- A115%
- B150%
- C200%
- D300%
31Which markings are used to designate the rotor terminals of a wound rotor motor?
- AL1 L2 L3
- BF1 F2 F3
- CM1 M2 M3
- DT1 T2 T3
32In order to not trip, what is the maximum percent rating for an instaneous trip circuit breaker of an AC motor?
- A700%
- B900%
- C1300%
- D1500%
33What is the speed of rotation of the magnetic field called in a three-phased motor?
- AMagnetic
- BSlip
- CSynchronous
- DRotor
34What is the proper rating of a time-delay fuse for a 230v, 22.38 KW, auto-transformer start continuous duty motor
- A100Amp
- B125Amp
- C150Amp
- D225Amp
35A three-phase motor has a synchronous speed of 1800RPM, operates at a frequency of 60Hz and has a slip speed of 100RPM. What is the rotor speed of the motor?
- A1700 RPM
- B1900 RPM
- C2000 RPM
- D2100 RPM
36What is the purpose of the centrifugal switch in split phase motor?
- AIt removes the start winding from the motor in split phase motors
- BIt adds the start winding from the motor circuit
- CIt removes the run winding from the motor circuit
- DIt adds the run winding from the motor circuit
37What is the speed at which the centrifugal switch of a split phase motor will operate?
- A60%
- B65%
- C70%
- D75%
38How is the rotor of a 15 hp synchronous motor operating on line voltage excited?
- AAC voltage
- BInduced magnetic field
- CAC line voltage
- DDC current
39Which starting method provides the highest torque per ampere?
- AAuto-transformer
- BAcross the line
- CPrimary resistor
- DWye-delta
40What part of the wound rotor motor differs from that of a squirrel cage induction motor?
- AStator
- BRotor
- CEnd bells
- DBearings
41What size time delay fuse can be used on a 3 phase, 230V, auto transformer starting motor consuming 22.38 KW of power
- A70 amps
- B80amps
- C90 amps
- D100amps
42What does increasing the frequency of the supply voltage to an induction motor cause?
- AIncreased speed
- BDecreases speed
- CIncreased torque
- DDecreased torque
43A nine-lead dual voltage three-phase SCIM is connected in the lower voltage delta arrangement. Which terminals are connected to each other?
- AL1-T1, T7-T4, L2-T2, T8-T5, L3-T3, T9-T6
- BL1-T1-T7-T6, L2-T2-T8-T4, L3-T3-T9-T5
- CL1-T1-T8, L2-T2-T7, L3-T3-T9, T4-T5-T6
- DL1-T1,L2-T2,L3-T3,T7-T4,T8-T5,T9-T6
44What is the ampacity of conductors feeding a 3 phase, 230V, SCIM, continuous duty motor rated at 20hp, 10hp, 1Hp, and 5Hp?
- A77.1A
- B88.3A
- C114.9A
- D116.6A
45What meter is used to check the input phasing before installing a three-phase motor?
- APhase rotation meter
- BWattmeter
- CMotor rotation meter
- DSyncroscope
46What effect does increasing the frequency of the supply have on the speed of the rotating magnetic field?
- AIncreases
- BDecreases
- CNo change
- DChanges direction
47How does the starting current of a split phase motor compare to its full load current?
- AIt’s much higher than the FLA
- BIt’s much lower than the FLA
- CIt’s equal to the FLA
- DIt’s equal to the stall current
48What information is required to size the overload protection of a 15Hp l, 600V, three-phase motor?
- AHP & FLA
- BSF AND FLA
- CV and FLA
- DWire size and SF
49A 5 Hp, 3 phase motor has a voltage of 208v and draw a 12A. It has a power factor of 95%. What is the efficiency?
- A75.6%
- B90.8%
- C110%
- D157%
50Which variables are identified by the motor service factor when considering the maximum continuous permissible load?
- AVoltage and amps
- BVoltage and frequency
- CAmps and frequency
- DRPM and voltage
51A synchronous motor has a lagging power factor. How is the corrected?
- AOver excite the field
- BAdd a capacitor
- CIncrease the load reduce the load
- DReduce the load
52Which 3 phase motor provides maximum starting torque?
- ACapacitor run
- BCapacitor start
- CInduction run
- DResistance run
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- Quiz on ER-2031, created by Kaitlyn Hickey on 03/02/2018.
- Author
- Kaitlyn Hickey
- Language
- English
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