In the construction of D.C. motors, parts of both the series and shunt fields are wound on the _____________. A. opposite main pole B. rotor core C. interpole D. same main pole

In the construction of D.C. motors, parts of both the series and shunt fields are wound on the _____________. A. opposite main pole B. rotor core C. interpole D. same main pole
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Answer: D
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In D.C. motor construction, commutating windings are wound on _________________. A. opposite main poles B. interpoles C. adjacent main poles D. the rotor core

Description : In D.C. motor construction, commutating windings are wound on _________________. A. opposite main poles B. interpoles C. adjacent main poles D. the rotor core

Last Answer : Answer: B

Shunt, series, and compound wound motors, are all DC motors designed to operate from _____________. A. constant potential, variable current DC sources B. variable potential, constant current DC sources C. variable potential, variable current DC sources D. constant potential, constant current DC sources

Description : Shunt, series, and compound wound motors, are all DC motors designed to operate from _____________. A. constant potential, variable current DC sources B. variable potential, constant current DC ... C. variable potential, variable current DC sources D. constant potential, constant current DC sources

Last Answer : Answer: A

What type of rotor is used in split-phase motors? A. Drum B. Salient pole C. Squirrel-cage D. Wound-rotor

Description : What type of rotor is used in split-phase motors? A. Drum B. Salient pole C. Squirrel-cage D. Wound-rotor

Last Answer : Answer: C

Relative to the direction of rotation, a D.C. motor commutating pole has the same polarity as the _____________. A. main pole following B. interpole following C. main pole preceding D. interpole preceding

Description : Relative to the direction of rotation, a D.C. motor commutating pole has the same polarity as the _____________. A. main pole following B. interpole following C. main pole preceding D. interpole preceding

Last Answer : Answer: C

One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for polarity using a/an ____________. A. iron bar across each field B. magnetic compass placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections

Description : One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for ... placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections

Last Answer : Answer: B

Which of the methods listed is used to maintain the division of load between two compound-wound, DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt field rheostats are interconnected. C. The series fields of both generators are connected in series. D. The equalizer connection parallels the series fields of all machines.

Description : Which of the methods listed is used to maintain the division of load between two compound-wound, DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt ... generators are connected in series. D. The equalizer connection parallels the series fields of all machines.

Last Answer : Answer: D

Which of the methods listed is used to maintain equal load sharing between two compound wound DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt field rheostats are interconnected. C. The series fields of both generators are connected in series. D. The series fields of both generators are connected in parallel.

Description : Which of the methods listed is used to maintain equal load sharing between two compound wound DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt field rheostats ... are connected in series. D. The series fields of both generators are connected in parallel.

Last Answer : Answer: D

Which of the following types of DC motors has its field connected in parallel with its armature? A. Counter EMF B. Shunt C. Salient pole D. Series

Description : Which of the following types of DC motors has its field connected in parallel with its armature? A. Counter EMF B. Shunt C. Salient pole D. Series

Last Answer : Answer: B

As shown in the illustration, part 'X' of the diagram is known as a/an _____________. EL-0052 A. commutator B. interpole C. starting pole D. auxiliary pole

Description : As shown in the illustration, part 'X' of the diagram is known as a/an _____________. EL-0052 A. commutator B. interpole C. starting pole D. auxiliary pole

Last Answer : Answer: B

In a series wound motor, the current passing through the field windings is also passing through the _____________. A. armature B. shunt field C. reactance comparator D. laminations

Description : In a series wound motor, the current passing through the field windings is also passing through the _____________. A. armature B. shunt field C. reactance comparator D. laminations

Last Answer : Answer: A

A variable shunt, connected across the series field coils of a DC compound wound generator, to permit adjustment of the degree of compounding, is called a _____________. A. divider B. diverter C. converter D. rheostat

Description : A variable shunt, connected across the series field coils of a DC compound wound generator, to permit adjustment of the degree of compounding, is called a _____________. A. divider B. diverter C. converter D. rheostat

Last Answer : Answer: B

The simplest method of controlling the terminal voltage of compound-wound DC generator is with a _____________. A. hand-operated field rheostat connected in series with the shunt field circuit B. separate exciter in a series with the shunt field C. carbon pile regulator in series with the load D. balance coil diverting neutral current through the shunt field

Description : The simplest method of controlling the terminal voltage of compound-wound DC generator is with a _____________. A. hand-operated field rheostat connected in series with the shunt field circuit B. ... in series with the load D. balance coil diverting neutral current through the shunt field

Last Answer : Answer: A

An equalizing connection between two compound-wound DC generators when paralleled, serves to _____________. A. reverse the polarity of the incoming generator as the series field weakens B. automatically equalize the power factors C. reverse the direction of current in the series field of the incoming generator D. parallel the series fields of the generators

Description : An equalizing connection between two compound-wound DC generators when paralleled, serves to _____________. A. reverse the polarity of the incoming generator as the series field weakens B. automatically ... the series field of the incoming generator D. parallel the series fields of the generators

Last Answer : Answer: D

Which of the following types of motors is often designed for use in correcting power factor? A. Polyphase B. Wound-rotor C. Induction D. Synchronous

Description : Which of the following types of motors is often designed for use in correcting power factor? A. Polyphase B. Wound-rotor C. Induction D. Synchronous

Last Answer : Answer: D

Methods to control speed of Wound Rotor Motors?

Description : Methods to control speed of Wound Rotor Motors?

Last Answer : The speed of wound rotor motors are changed by changing the slip of the motor. This can be achieved by: Varying the stator line voltage Varying the resistance in the rotor circuit Inserting and varying a foreign voltage source in the rotor circuit

A motor which can conveniently be operated at lagging as well as leading power factors is the (A) squirrel cage induction motor. (B) wound rotor induction motor. (C) synchronous motor. (D) DC shunt motor.

Description : A motor which can conveniently be operated at lagging as well as leading power factors is the (A) squirrel cage induction motor. (B) wound rotor induction motor. (C) synchronous motor. (D) DC shunt motor.

Last Answer : (C) synchronous motor.

The introduction of interpoles in between the main pole improves the performance of d.c. machines, because (A) The interpole produces additional flux to augment the developed torque. (B) The flux waveform is improved with reduction in harmonics. (C) The inequality of air flux on the top and bottom halves of armature is removed. (D) A counter e.m.f. is induced in the coil undergoing commutation.

Description : The introduction of interpoles in between the main pole improves the performance of d.c. machines, because (A) The interpole produces additional flux to augment the developed torque. (B) The flux waveform is ... armature is removed. (D) A counter e.m.f. is induced in the coil undergoing commutation.

Last Answer : Ans: D Counter e.m.f is produced, it neutralizes the reactive emf.

A single-phase induction motor having a relatively high starting torque, is the ___________. A. shaded pole motor B. wound-rotor motor C. capacitor-start motor D. resistance-start motor

Description : A single-phase induction motor having a relatively high starting torque, is the ___________. A. shaded pole motor B. wound-rotor motor C. capacitor-start motor D. resistance-start motor

Last Answer : Answer: C

A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf? (A) 100 Volts. (B) 0.1 Volts. (C) 1 Volts. (D) 10 Volts.

Description : A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf? (A) 100 Volts. (B) 0.1 Volts. (C) 1 Volts. (D) 10 Volts.

Last Answer : Ans: D Given N = 1500 rpm, Φ = 0.4 mWb, Z = 1000, P = 4, & A= 4 Therefore, Eb = NΦPZ / 60 A = 1500 x 0.4 x 4 x 1000 x 10^-3 / 60 x 4 = 60/6 = 10 volts

In the illustrated device, the part labeled '1A' _________. EL-0001 A. are start and run windings for a single phase shaded pole induction motor B. is the stator for a polyphase induction motor C. is the armature for a squirrel cage rotor motor D. are direct current shunt field windings for a universal motor

Description : In the illustrated device, the part labeled '1A' _________. EL-0001 A. are start and run windings for a single phase shaded pole induction motor B. is the stator for a polyphase induction ... armature for a squirrel cage rotor motor D. are direct current shunt field windings for a universal motor

Last Answer : Answer: B

A characteristic of a wound-rotor induction motor, with a high resistance rotor winding, is _____________. A. low starting torque B. high starting torque C. high speed D. low starting voltage

Description : A characteristic of a wound-rotor induction motor, with a high resistance rotor winding, is _____________. A. low starting torque B. high starting torque C. high speed D. low starting voltage

Last Answer : Answer: B

Reversing any two of the three rotor leads on a wound-rotor induction motor will _____________. A. increase motor performance B. decrease motor performance C. reverse the motor rotation D. have no effect on the direction of rotation or motor performance

Description : Reversing any two of the three rotor leads on a wound-rotor induction motor will _____________. A. increase motor performance B. decrease motor performance C. reverse the motor rotation D. have no effect on the direction of rotation or motor performance

Last Answer : Answer: D

The speed of a wound-rotor induction motor _____________. A. will be fixed by the number of field poles B. can be varied by a rheostat-type control C. can only be synchronous speed at full load D. can only attain synchronous speed at no load

Description : The speed of a wound-rotor induction motor _____________. A. will be fixed by the number of field poles B. can be varied by a rheostat-type control C. can only be synchronous speed at full load D. can only attain synchronous speed at no load

Last Answer : Answer: B

Why wound rotor construction is adopted?

Description : Why wound rotor construction is adopted?

Last Answer : The wound rotor has the facility of increasing the rotor resistance through slip rings. High value of rotor resistance is needed during starting to get a high value of starting torque.

In a compound-wound motor, a portion of the line current flows through the _____________. A. inertial poles B. stator C. shunt field coils D. frame

Description : In a compound-wound motor, a portion of the line current flows through the _____________. A. inertial poles B. stator C. shunt field coils D. frame

Last Answer : Answer: C

A shunt-wound DC generator is one in which the shunt field windings are in parallel with the _____________. A. commutator B. brushes C. armature D. all of the above

Description : A shunt-wound DC generator is one in which the shunt field windings are in parallel with the _____________. A. commutator B. brushes C. armature D. all of the above

Last Answer : Answer: D

The air gap provided in induction motors should be checked periodically with a feeler gage to detect an unequal air gap and _____________. A. decreased motor magnetizing current B. hysteresis loses C. increased power factor D. mechanical damage to the rotor

Description : The air gap provided in induction motors should be checked periodically with a feeler gage to detect an unequal air gap and _____________. A. decreased motor magnetizing current B. hysteresis loses C. increased power factor D. mechanical damage to the rotor

Last Answer : Answer: D

An operating characteristic appearing on the name plates of shipboard AC motors is _____________. A. the type of winding B. input kilowatts C. temperature rise D. locked rotor torque

Description : An operating characteristic appearing on the name plates of shipboard AC motors is _____________. A. the type of winding B. input kilowatts C. temperature rise D. locked rotor torque

Last Answer : Answer: C

A ground can be defined as an electrical connection between the wiring of a motor and its ____________. A. shunt field B. circuit breaker C. metal framework D. interpole

Description : A ground can be defined as an electrical connection between the wiring of a motor and its ____________. A. shunt field B. circuit breaker C. metal framework D. interpole

Last Answer : Answer: C

The electrical diagram shown in the illustration represents a ___________. EL-0054 A. series-wound motor B. shunt-wound motor C. compound-wound motor D. flat-compounded motor

Description : The electrical diagram shown in the illustration represents a ___________. EL-0054 A. series-wound motor B. shunt-wound motor C. compound-wound motor D. flat-compounded motor

Last Answer : Answer: C

An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from _____________. A. one line terminal to each coil lead in succession B. one field coil to each adjacent field coil in turn C. any suitable ground to any available line lead D. any field pole to each field coil lead

Description : An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from ... C. any suitable ground to any available line lead D. any field pole to each field coil lead

Last Answer : Answer: A

As shown in the illustration, the electrical symbol is used to indicate which of the listed types of motors? EL-0054 A. Shunt motor. B. Series motor. C. Compound motor. D. Tri-field motor.

Description : As shown in the illustration, the electrical symbol is used to indicate which of the listed types of motors? EL-0054 A. Shunt motor. B. Series motor. C. Compound motor. D. Tri-field motor.

Last Answer : Answer: C

Which of the following operating characteristics for DC motors is considered to give high starting torque? A. series B. shunt C. cumulative-compound D. differential-compound

Description : Which of the following operating characteristics for DC motors is considered to give high starting torque? A. series B. shunt C. cumulative-compound D. differential-compound

Last Answer : Answer: A

Regenerative braking (A) Can be used for stopping a motor. (B) Cannot be easily applied to DC series motors. (C) Can be easily applied to DC shunt motors (D) Cannot be used when motor load has overhauling characteristics.

Description : Regenerative braking (A) Can be used for stopping a motor. (B) Cannot be easily applied to DC series motors. (C) Can be easily applied to DC shunt motors (D) Cannot be used when motor load has overhauling characteristics.

Last Answer : Ans: B Because reversal of Ia would also mean reversal of field and hence of Eb

As compared to shunt and compound DC motors, the series DC motor will have the highest torque because of its comparatively ____________ at the start. (A) Lower armature resistance. (B) Stronger series field. (C) Fewer series turns. (D) Larger armature current.

Description : As compared to shunt and compound DC motors, the series DC motor will have the highest torque because of its comparatively ____________ at the start. (A) Lower armature resistance. (B) Stronger series field. (C) Fewer series turns. (D) Larger armature current.

Last Answer : (D) Larger armature current.

In a three-phase, squirrel-cage type, induction motor the rotating magnetic field is established by the _____________. A. current induced in the rotor windings B. application of a three-phase voltage supply to the stator windings C. laminated steel core and aluminum conductors in the rotor D. interaction of the magnetic field caused by the induced current in the squirrel-cage bars with the magnetic field of the stator

Description : In a three-phase, squirrel-cage type, induction motor the rotating magnetic field is established by the _____________. A. current induced in the rotor windings B. application of a three-phase voltage ... caused by the induced current in the squirrel-cage bars with the magnetic field of the stator

Last Answer : Answer: B

An 8 pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 r.p.m. by a prime mover in

Description : An 8 pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 r.p.m. by a prime mover in the opposite direction of revolving magnetic field. The frequency of the rotor current is (a) 30 Hz (b) 60 Hz (c) 120 Hz (d) 180 Hz 

Last Answer : 30 Hz As the frequency of the rotor is given by  F= N*P/120 so from the above equation the frequency of the rotor current can be easily calculated  i.e. 1800×8/120=30 Hence the required value of rotor frequency is 30 Hz

A 6 pole 3-phase wound-rotor induction machine is driven by another machine at 1800 rpm. The rotor of the ...

Description : A 6 pole 3-phase wound-rotor induction machine is driven by another machine at 1800 rpm. The rotor of the induction machine is connected to a 50Hz system. If the mechanical rotation of the rotor is in the same direction as the rotor winding flux rotation, then frequency of the stator voltage will be

Last Answer : A 6 pole 3-phase wound-rotor induction machine is driven by another machine at 1800 rpm. The rotor of the induction machine is connected to a 50Hz system. If the mechanical rotation of ... the same direction as the rotor winding flux rotation, then frequency of the stator voltage will be 140 Hz.

The direction of rotation of a DC propulsion motor can be changed by reversing the _____________. A. brush holder position B. polarity of the field poles C. brush staggered order D. motor interpole connections

Description : The direction of rotation of a DC propulsion motor can be changed by reversing the _____________. A. brush holder position B. polarity of the field poles C. brush staggered order D. motor interpole connections

Last Answer : Answer: B

An 8 pole lap wound DC shunt generator is supplying 295A to a load. The field current of the generator is 5A....

Description :  An 8 pole lap wound DC shunt generator is supplying 295A to a load. The field current of the generator is 5A. The current per parallel path is: -  a) 300A b) 200A c) 150A d) 37.5A

Last Answer :  An 8 pole lap wound DC shunt generator is supplying 295A to a load. The field current of the generator is 5A. The current per parallel path is: - 37.5A

Which type of AC single-phase motor will also operate on direct current? A. Split-phase B. Series-wound C. Shaded-pole D. Repulsion-start

Description : Which type of AC single-phase motor will also operate on direct current? A. Split-phase B. Series-wound C. Shaded-pole D. Repulsion-start

Last Answer : Answer: B

A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor magnets to lock in with the rotating flux of the stator C. the stator poles are dragged around due to the flux created by the excitation current D. the stator flux rotates in the opposite direction

Description : A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor ... the flux created by the excitation current D. the stator flux rotates in the opposite direction

Last Answer : Answer: B

Deep bar rotor construction is used in three phase induction motors to mainly:

Description : Deep bar rotor construction is used in three phase induction motors to mainly: (1) Control speed (2) Control power factor (3) Increase starting torque (4) None of these

Last Answer : Deep bar rotor construction is used in three phase induction motors to mainly: Increase starting torque

To limit the current flow through a DC voltmeter to as low a value as possible, the moving coil circuit is provided with a/an _____________. A. high series resistance B. high parallel resistance C. series inductor D. external shunt

Description : To limit the current flow through a DC voltmeter to as low a value as possible, the moving coil circuit is provided with a/an _____________. A. high series resistance B. high parallel resistance C. series inductor D. external shunt

Last Answer : Answer: A

Current measuring instruments must always be connected in _____________. A. series with a circuit B. parallel with a circuit C. series-parallel with a circuit D. delta with the shunt

Description : Current measuring instruments must always be connected in _____________. A. series with a circuit B. parallel with a circuit C. series-parallel with a circuit D. delta with the shunt

Last Answer : Answer: A

A DC shunt generator has its field windings connected in _____________. A. series with the series windings B. parallel with the field rheostat C. series with the armature windings D. parallel with the armature windings

Description : A DC shunt generator has its field windings connected in _____________. A. series with the series windings B. parallel with the field rheostat C. series with the armature windings D. parallel with the armature windings

Last Answer : Answer: D

The basic control action of a magnetic amplifier depends upon _____________. A. variations in the load capacitance B. changes in inductance C. type of core material D. construction of the core

Description : The basic control action of a magnetic amplifier depends upon _____________. A. variations in the load capacitance B. changes in inductance C. type of core material D. construction of the core

Last Answer : Answer: B

As shown in the illustration, the motor generator(M-G) set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Description : As shown in the illustration, the motor generator(M-G) set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Last Answer : Answer: C

As shown in the illustration, the M-G set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Description : As shown in the illustration, the M-G set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Last Answer : Answer: C