What is the difference between AC voltage and DC voltage?

6 Answers  

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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 )

3 Answers   NTPC, Transco,

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7- What is the Dissipation Factor and the difference between it and Insulation Resistance Test? 8- What is the task (function) of DC and AC reactors in power plant? 9- What is the task (function) of (open delta with earthed) in some types in transformers? 10- What is the base of the selection of the vector group in transformers? 11- What is the zig-zag transformer and its function by drawing in large detail? 12- What is the polarity ? 13- Why we make short between phase(R) in high side and phase (r) in low side in vector group test? Where High Side ( R ,S and T ) and Low Side ( r ,s and t ). 14- What are the time on delay and time off delay? 15- What is the vector group? 15- What is the task (function) of different types of vector group such as Dyn11 , Dd0 , YNd1,……..,?

0 Answers  

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what will happen if dc machine are supplied by ac source??

2 Answers  

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For a three phase induction motor, what will be the effect on motor if the neutral of the system is shifted to say 20 deg.?

0 Answers  

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Why is it that bus reactors are not accompanied by a neutral grounding reactor whereas a line shunt reactor is? PGCIL does so.

2 Answers  

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what is the meaning write of AC1,AC2,AC3 .....power contactor

7 Answers   ABB,

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is all the servo motors having brake?please specify which servo motors having brake for stop on position and which are not.

0 Answers  

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please let me know , we have installed two separate motor for fire fighting system 1) 60 hp and 2) 15 hp the load is 74 AMPS and 20 AMPS then tell me the main power cable in Aluminum will be what thickness , the length is 225 mt from the main utility to fire pump house

1 Answers  

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My requirement is 1VA,50/5A Current Transformer for Metering .If I select 15VA , 50/5A CT.Is there any possibility of Technical Problem ?

6 Answers  

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Why the power generated in dams is complex power? Why the generators in dams cannot produce Real power directly (i.e power which has zero reactive part)?

0 Answers  

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why we r using 4-20ma instead of 0-20ma in instrumentation

2 Answers   EID Parry,

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