Answer / rakesh ranjan sharma

It is the process by which the reversed polarity of residual magnetism can be corrected by using an external dc source to remagnetise the field poles in correct direction.........

Answer / monika

In alternators it is necessary to have some resudual
voltage to buildup an voltage. The residual voltages
weakens because of ageing & keeping at rest condition for
long time. In this cases using external DC sourses will
applied to field terminals to create residual. This process
is called as field flashing.

Answer / k.prakashchandra

Static exciter uses thyristors for converting AC to
DC .Thyristers require a minimum voltage to conduct,for
which the voltage created by residual magnetism is not
sufficient.To bring the generator volage to the required
value ,field flashing is done with dc source or AC through
rectifier.Once the required voltage is built up,the
generator output will take over the excitation with field
flashing off

Answer / kumar

I can't clear about this question but in alternator we
flash the field in RR(rotating rectifier)by give the Dc
voltage directly to field Its the method for developing AC
voltage

Define the three phase formula fuse.

0 Answers   ABC, Gayatri, UPCL,

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Kindly give the brief explanations for checking 12.5 kvar 440V, 25 KVAR 440V, 12.5KVAR 690V, 25 KVAR 690V capacitors microfarad values. what is the microfarad values for the above four type of capacitors, and give the formula explanations briefly. I know F-50HZ, voltage, and capacitor.

1 Answers  

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What is the formula for calculating impedance of transformers connected parallel at fault level 50KA?

0 Answers  

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what is mean by tan-delta tap in the potential transformer??

2 Answers  

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HOW BETTER VOLTAGE REGULATION IS OBTAINED BY HIGH VOLTAGE TRANSMISSION....?

1 Answers   Cummins,

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through which medium return supply given to alternator please answer in details

1 Answers   MahaGenco,

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What is effect on in zone and out zone fault if CT chosen for phase side is Vk/2<5mA and Neutral side is Vk/2<15mA on REF protection of Transformer

0 Answers   ABB,

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what are the types of starter ?

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What is Harmonics how it is produced and what is the method to control the same

0 Answers   Siemens,

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what is metering cum synchronizing panel and how it is used?

0 Answers   Wipro,

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describe the fully control circuit diagram of ac drives

0 Answers  

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Necessity of transformer earthing

1 Answers  

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