Explain What will happen when direction of field current is changed (i.e, fiel

Explain What will happen when direction of field current is
changed (i.e, field excitation is reversed) in the
following machines?
1) Alternator
2) Synchronous Motor
3) D.C Generator ( Shunt or Seies )
4) D.C Motor ( Shunt or Seies )

Question Posted / anil

3 Answers
18235 Views
NTPC, Transco, I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

Explain What will happen when direction of field current is changed (i.e, field excitation is reve..

Answer / tpfasil200

Direction of rotation of synchronous motor is determined b y its starting direction,as initiated by inducyion motor action. Thus, to reverse the direction of a 3 phase synchronous motor, it is necessary to first stop the motor and then reverse the phase sequence of the 3 phase connections at the stator. REVERSING THE CURRENT TO FIELD WINDINGS WILL NOT AFFECT THE DIRECTION OF ROTATION

Is This Answer Correct ?

25 Yes

2 No

Explain What will happen when direction of field current is changed (i.e, field excitation is reve..

Answer / tpfasil200

Direction of rotation of dc motor can be reversed in 2 ways
1.reversing current through armature and interpole windings(if they exist)
2.reversing current through field windings,ie,through shunt and/or series winding..but not through interpole windings(if they exist)
Reversing current through the armature is preferred because reversing current through the field windings involves breaking and making highly inductive currents of the field windings.Also field reversal of compound motors requires connections of both shunt and series windings to be changed..

Is This Answer Correct ?

18 Yes

1 No

Explain What will happen when direction of field current is changed (i.e, field excitation is reve..

Answer / prasanth

1.in alternator the induced emf is reduced due to retentive property of the field magnet when reversed.

Is This Answer Correct ?

0 Yes

2 No

Post New Answer

More Electrical Engineering Interview Questions

why free wheeling diode is connected across inductive load

16 Answers NTPC, Omaxe, Wipro,

How to increase the specific gravity of DG batteries?

3 Answers SCS,

how to calculate the breaking capacity of different breakers.

0 Answers UltraTech,

WHY MOSTLY Rph IS USED FOR CONTROL CIRCUITS AUX. SUPPLY ?

0 Answers UltraTech,

which cable is used for 15 Hp monoblock pump 3phase and service wire Distance is 210 feet please tell me cable size Armaured

0 Answers

why in scott connection of transformers, main transformer is tapped at 50% and teaser transformer at 86.6%?

5 Answers Bhel, Bosch, College School Exams Tests, Wipro,

please tell me the all the spcications of the 100MW 11KV HYDEL POWER PLANT SPECICATIONS

2 Answers Bhel,

Details about Flux Compensated magnetic Amplifer starter for motors

0 Answers

Name quantities which are not transformed in the tranformer.

3 Answers

why the transformer secondary voltage is more than the load end voltage like t/f 11KV/433V for 415V(terminal voltage)

4 Answers

how to calculate lux level in out door (yard lighting) please expalin with a example

1 Answers IVRCL,

Can earth resistance be measured without connecting the earth electrode? and should earthing connections be disconnected What is the effect of connecting two cables of different sizes in parallel with supply? Thanks in Advance. I am intrested to get in touch with some tecnocrats/engineers,my mail i.d is : hiremathvijay@rediffmail.com

1 Answers

For more Electrical Engineering Interview Questions Click Here