Answer :
In case of a shaded pole motor the direction of rotation of the motor is from main pole to shaded pole.
asked
Mar 20, 2018
by
anonymous
Answer :
In a shaded pole single-phase motor, the revolving field is produced by the use of shading coils.
asked
Mar 20, 2018
by
anonymous
Answer :
A shaded pole motor can be used for toys, hair dryers, circulators etc.
asked
Mar 20, 2018
by
anonymous
Description : With a neat sketch give the working of shaded pole induction motor.
Answer :
Explanation: It has squirrel cage rotor and salient pole stator. The stator poles are shaded partially by short circuited conductor band to create the phase difference between the fluxes emerging from shaded ... rotating magnetic field in the air-gap and torque is exerted on the squirrel cage rotor.
asked
Apr 27, 2020
by
anonymous
Answer :
Locked rotor current of a shaded pole motor is slightly more than full load current.
asked
Mar 20, 2018
by
anonymous
Description : State two applications of 1) Shaded pole motor 2) Universal motor
Answer :
(i)Applications of Shaded pole motor: 1. Small fans 2. Toy motors 3. Hair dryers 4. Ventilators 5. Electric clocks 6. Record players 7. Motorized valves 8. Gramophones 9. Photocopying ... 5. Portable Drilling Machines 6. Electric Shavers 7. Mechanical computing Machines 8. Machine Tools etc.
asked
Jul 26, 2019
by
anonymous
Answer :
The shaded pole motor is used for low starting torque.
asked
Mar 20, 2018
by
anonymous
Answer :
The range of efficiency for shaded pole motors is 5% to 35%.
asked
Mar 20, 2018
by
anonymous
Answer :
The torque produced in induction type relay (shaded pole structure) is inversely proportional to the square of the current.
asked
Mar 20, 2018
by
anonymous
Answer :
The power factor of a single-phase induction motor is usually lagging.
asked
Mar 20, 2018
by
anonymous
Answer :
In a A.C. series motor armature coils are usually connected to commutator through resistance.
asked
Mar 20, 2018
by
anonymous
Answer :
The efficiency of a properly designed synchronous motor will usually fall in range 85 to 95%.
asked
Mar 20, 2018
by
anonymous
Answer :
If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will stop.
asked
Mar 20, 2018
by
anonymous
Description : what will happen when excitation of an unloaded salient pole synchronous motor suddenly gets disconnected?
Answer :
When excitation of an unloaded salient pole synchronous motor suddenly gets disconnected the motor will stop.
asked
Mar 18, 2018
by
anonymous
Answer :
The adjustment of position of shading bands, in an energy meter is done to provide friction compensation.
asked
Mar 21, 2018
by
anonymous
Description : State the function of overload coil and No volt coil in dc motor starter.
Answer :
Function of Overload Coil: When DC motor is overloaded, the overload coil carries the overload current and produces strong magnetic field to attract a plunger, which short the terminals of ... dc motor is prevented from restarting automatically on recovery of supply without starter and protected.
asked
Jul 27, 2019
by
anonymous
Description : Power factor of an inductive circuit is usually improved by connecting capacitor to it in?
Answer :
Power factor of an inductive circuit is usually improved by connecting capacitor to it in parallel.
asked
Mar 25, 2018
by
anonymous
Answer :
The braking retardation is usually in the range 10 to 15 km phps.
asked
Mar 22, 2018
by
anonymous
Answer :
The voltage used for suburban trains in D.C. system is usually 600 to 750 V.
asked
Mar 22, 2018
by
anonymous
Answer :
Single phase induction motor usually operates on 0.6 power factor lagging.
asked
Mar 20, 2018
by
anonymous
Answer :
The motor used on small lathes is usually single-phase capacitor run motor.
asked
Mar 20, 2018
by
anonymous
Answer :
Overload capacity of diesel engines is usually restricted to 2 percent.
asked
Mar 22, 2018
by
anonymous
Description : A 50 Hz, 4 pole turboalternator rated at 20 MVA. 13.2 KV has an inertia constant H = 4 KW sec/KVA. The K.E. stored in the rotor at synchronous speed is
Answer :
A 50 Hz, 4 pole turboalternator rated at 20 MVA. 13.2 KV has an inertia constant H = 4 KW sec/KVA. The K.E. stored in the rotor at synchronous speed is 80 MJ
asked
May 3, 2018
by
anonymous
Description : The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) (A) has q -axis current only (B) has d -axis current only (C) has both d and q axis currents (D) cannot be divided between q and d axis currents
Answer :
The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) has d -axis current only
asked
Apr 29, 2018
by
anonymous
Description : Salient pole rotor is use for which speed?
Answer :
Salient pole rotor is use for low and medium speed prime movers.
asked
Mar 18, 2018
by
anonymous
Description : Explain MOSFET gate drive circuit and totem pole configuration.
Answer :
MOSFET gate drive circuit: The turning on and turning off of MOSFET can be controlled from gate to source voltage signal. If the gate to source voltage of MOSFET exceeds threshold ... this configuration, the two switches (transistors) are used in totem pole arrangement with a comparator.
asked
Feb 19, 2018
by
anonymous
Description : The purpose of the restraining coil in a biased differential relay is (A) To reduce CT saturation during fault. (B) To increase the sensitivity of the relay. (C) To match the transformation ratio. (D) To limit the spill current through the relay during heavy external fault.
Answer :
d
asked
May 8, 2018
by
anonymous
Answer :
In a low power factor wattmeter the compensating coil is connected in series with pressure coil.
asked
Mar 21, 2018
by
anonymous
Answer :
In a low power factor wattmeter the pressure coil is connected to the load side of the current coil.
asked
Mar 21, 2018
by
anonymous
Answer :
The multiplier and the meter coil in a voltmeter are in series.
asked
Mar 21, 2018
by
anonymous
Description : Name the material used for :- (i) Moving coil (ii) Permanent magnet in PMMC instrument.
Answer :
(i) Material used for Moving coil: Copper, Aluminum( some times) (ii) Permanent magnets are made of special alloys such as : Aluminum-Nickel-Cobalt (Alnicos) Strontium-Iron Neodymium-Iron-Boron Samarium-Cobalt.
asked
Sep 6, 2018
by
anonymous
Description : A moving coil of meter has 100 turns, and a length and depth of 10mm and 20mm respectively. It is positioned in a uniform radial flux density of 200 mT. The coil carrier current capacity is 50 mA. The torque on the coil is
Answer :
A moving coil of meter has 100 turns, and a length and depth of 10mm and 20mm respectively. It is positioned in a uniform radial flux density of 200 mT. The coil carrier current capacity is 50 mA. The torque on the coil is 200µNm
asked
Apr 29, 2018
by
anonymous
Description : A Peterson coil is ________ A) An arc generating coil B) An arc suppressing coil C) An arc inducing coil D) None of these
Answer :
A Peterson coil is An arc suppressing coil
asked
Apr 29, 2018
by
anonymous
Description : The self inductance of a coil can be measured using (A) Wien’s Bridge (B) Schering Bridge (C) Anderson’s Bridge (D) Wheatstone Bridge
Answer :
The self inductance of a coil can be measured using Anderson’s Bridge
asked
Apr 28, 2018
by
anonymous
Description : A PMMC instrument has FSD of 100 μA and a coil resistance of 1 kΩ. To convert the instrument into an ammeter with full scale deflection of 100 mA, the required shunt resistance is (A) 1 Ω (B) 1.001 Ω (C) 0.5 Ω (D) 10 Ω
Answer :
A PMMC instrument has FSD of 100 μA and a coil resistance of 1 kΩ. To convert the instrument into an ammeter with full scale deflection of 100 mA, the required shunt resistance is 1.001 Ω
asked
Apr 28, 2018
by
anonymous
Description : A moving coil meter has a resistance of 3 Ω and gives full scale deflection with 30 mA. To measure voltage up to 300 V, the external resistance to be connected in series with the instrument is (A) 9997 Ω (B) 10000 Ω (C) 997 Ω (D) 10003 Ω
Answer :
A moving coil meter has a resistance of 3 Ω and gives full scale deflection with 30 mA. To measure voltage up to 300 V, the external resistance to be connected in series with the instrument is 9997 Ω
asked
Apr 28, 2018
by
anonymous
Description : lt the length, number of turns and area of a coil are doubled, the inductance of the coil
Answer :
lt the length, number of turns and area of a coil are doubled, the inductance of the coil is quadrupled
asked
Apr 26, 2018
by
anonymous
Description : The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is 220 V. With the potential coil connected on the load side, the meter indicates 100 W. Approximate percentage error due to wattmeter connection is (A) 11% (B) 9% (C) 1.1% (D) 3%
Answer :
The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is 220 V. With the potential coil connected on the load side, the meter indicates 100 W. Approximate percentage error due to wattmeter connection is 11%
asked
Apr 25, 2018
by
anonymous
Description : The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is_______Vs.
Answer :
The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is 20 Vs
asked
Mar 25, 2018
by
anonymous
Description : The inductance of a coil can be increased by?
Answer :
The inductance of a coil can be increased by choosing core material having high relative permeability.
asked
Mar 25, 2018
by
anonymous
Description : Inductance of a coil Varies?
Answer :
Inductance of a coil Varies as directly as the cross-sectional area of magnetic core and inversely as the length of the iron path.
asked
Mar 25, 2018
by
anonymous
Answer :
A moving-coil permanent-magnet instrument can be used as flux-meter by eliminating the control springs.
asked
Mar 21, 2018
by
anonymous
Answer :
A moving-coil permanent-magnet instrument can be used as ammeter by using a low resistance shunt.
asked
Mar 21, 2018
by
anonymous
Answer :
Open circuited armature coil of a D.C. machine is identified by the scarring of the commutator segment to which open circuited coil is connected and indicated by a spark completely around the commutator.
asked
Mar 20, 2018
by
anonymous
Description : What is the difference between a coil and an inductor?
Answer :
Inductor is covering with insulating material is called coil.so they differentiate between coil and inductor.
asked
Dec 16, 2017
by
anonymous
Description : State the material used for moving coil and former for PMMC instruments.
Answer :
Material Used for Moving Coil and Former for PMMC Instruments: Material used for moving coil: Copper Material used for Former: Aluminium
asked
Sep 5, 2018
by
anonymous
Description : Permanent magnet moving coil instruments are used for
Answer :
PMME are mostly used for measuring voltage and current.
asked
May 8, 2018
by
anonymous
Description : Peterson coil is used for : (A) shunt compensation of lines (B) grounding of system neutral (B) reduce fault currents (D) connecting interconnected systems
Answer :
Peterson coil is used for : grounding of system neutral
asked
Apr 29, 2018
by
anonymous
Description : The rate of rise of current through an inductive coil is maximum?
Answer :
The rate of rise of current through an inductive coil is maximum at the start of the current flow.
asked
Mar 25, 2018
by
anonymous
Description : Inductance of coil?
Answer :
Inductance of coil increases with the increase in supply frequency.
asked
Mar 25, 2018
by
anonymous