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

Can any one give an explanation about rating factors of cable? if we are laying the cable on the air with an temp 15 degree then rating factors will be 1.15 and if we are laying the cable on the air an temp 60 degree then rating factor will be 0.76 please describe it and what is the difference between rating factor and derating factor?

0 Answers  

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which protection are used for turbo generator in thermal power plant.

1 Answers   Grasim,

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0 Answers  

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In ac which gas will be use?

2 Answers  

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what is phase voltage and phase current what is line current and line phase

3 Answers   L&T,

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3 Answers  

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What happen if we re-start H.T motor whose rotor is running at 40% rated speed. Is it will damage motor winding?

1 Answers  

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What are the temperature elements?

0 Answers  

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what is the formula for converting KW into KWH ?

3 Answers   Blue Star, Essar,

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If a fan get trip and run in reverse direction due to system flow. Now in this condition during starting how can a VFD bring this negative speed to zero and later run in forward direction?

2 Answers   Aditya Birla, Siemens,

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how can we select the type of wire.what factors we have to look on it , do we have some formula to calculate it. please guide me on it

0 Answers  

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What is Phase to Phase clearance for 800V System Operating Voltage as per IEC61439

0 Answers  

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