Recent questions and answers in DC machine

0 answers 29 views
1 answer 22 views

A DC shunt motor has rated rpm of 480. Certain industrial application requires this motor to run at 540 rpm for some time. Which speed control will be desirable? A) Ward Leonard control B) Armature current control C) Field resistance control D) It is not possible to run the motor at more than the rated rpm 

answered Jun 17, 2018 in DC machine
0 answers 10 views

The induced emf in the armature of a wave wound 4-pole d.c. machine having 100 armature conductors rotating at 600 r.p.m. and with a flux of 1 Wb per pole is (a) 1000 V (b) 2000 V (c) 200 V (d) 100 V

asked May 25, 2018 in DC machine
1 answer 29 views

A separately excited d.c. machine is coupled to a 50 Hz, three-phase, 4-pole induction machine as shown in the figure. The Dc machine is energized first and the machines rotate at 1 600 1pm. Subsequently the induction machine is also connected to a 50 Hz, three phase source, the phase sequence being consistent with the direction of rotation. In steady state

answered May 20, 2018 in DC machine
1 answer 17 views

A 50 kW dc shunt is loaded to draw rated armature current at any given speed. When driven  (i) at half the rated speed by armature voltage control and (ii) at 1.5 times the rated speed by field control, the respective output powers delivered by the motor are approximately. (A) 25 kW in (i) and 75 kW in (ii) (B) 25 kW in (i) and 50 kW in (ii) (C) 50 kW in (i) and 75 kW in (ii) (D) 50 kW in (i) and 50 kW in (ii)

answered May 17, 2018 in DC machine
1 answer 14 views

In a DC machine, which of the following statements is true ?  (A) Compensating winding is used for neutralizing armature reaction while interpole winding is used for producing residual flux (B) Compensating winding is used for neutralizing armature reaction while interpole winding is used for improving ... winding is used for neutralizing armature reaction (D) Compensation winding is used for improving commutation while interpole winding is used for producing residual flux

answered May 17, 2018 in DC machine
1 answer 38 views

What are the slot wedges in a DC machine made of?   (a) Mild steel (b) Silicon steel (c) Fibre (d) Cast iron

answered May 13, 2018 in DC machine
1 answer 21 views

For continuously running rolling mills with intermittent loading, the most suitable DC drive is   (a) DC series motor (b) DC shunt motor (c) DC differentially compound motor (d) DC cumulatively compound motor 

answered May 13, 2018 in DC machine
1 answer 17 views

Fractional pitch windings are used in DC machines to (A) Reduce copper losses (B) Improve cooling (C) Increase the generated emf (D) Reduce sparking

answered May 12, 2018 in DC machine
Help get things started by asking a question.

Welcome to here you can ask questions related to electrical, electronics, mechanical, telecommunication, instrumentation, computer, mathematics, physics etc.
Be respectful to all the members. Do not copy and paste the answers from other websites which have copyright content. While asking question give full details about it.


Most popular tags

power motor dc circuit transformer voltage current used system phase resistance factor synchronous load ac energy induction electric generator series frequency between speed capacitor use electrical meter line difference control type mosfet transmission magnetic plant high single instrument bjt unit source advantages function diode and machine winding field define torque parallel amplifier supply shunt thyristor motors electricity arduino maximum time relay armature problem value on transformers types coil diagram state flow ratio material three formula starting direction theorem method emf operating efficiency digital wave microprocessor test instruments inductance loss measure operation connected signal low applications effect single-phase network temperature working constant losses different law wattmeter measuring compare controlled breaker drive device logic rc full switch flux wire resistivity disadvantages free of materials machines angle force converter conductor transistor gain open protection scr core measurement number bridge principle generators reactance circuits negative the friction iron loop short pole battery conservation steam resistors hysteresis computer using analog lines secondary station gate a rectifier inverter linear induced relays nuclear capacitance basic characteristics design direct work rotor electronics ammeter forces diesel damping rlc connection factors capacitors minimum insulation moving regulation running self systems air fault range main stability quality starter igbt eddy alternator ideal rl average 3-phase plants arc thermal error fuzzy biasing dielectric pressure balanced superposition errors copper rotation feedback impedance measured electronic electrons charge inductive transfer explain start off back curve over solar is three-phase tariff locomotive peak bias zener engineering commutator surge conductors rating universal potentiometer density permanent mechanical transducer capacity memory adc excitation two fuse pure harmonics application semiconductor inductor internal pmmc reaction welding resonance traction permeability breakers rms designed electromagnetic si generation brushes switching capacitive shaded rate 1 distribution resistor methods delta star oscillator reluctance simplification algebra 8085 boolean weston dynamometer insulating strength installation definition fuel heating earth units

8,496 questions

7,094 answers


3,088 users