Answer / sunil kumar sinha

An alternator is AC generator. It will generate power only
when it is rotated by a prime mover and supplied electrical
field in its rotor circuit. The alternator when producing
electric power is connected with grid and supply electric
power. Here the prime mover supplies active power and field
maintains the voltage.
when primemover fails but excitor supplies rotor field, the
alternator will continue to rotate on grid frequency for
which it will draw power from grid. the reverse power will
flow, nothing wrong will hapen with alternator but if prime
mover is steam turbine there is every possibility of rotor
blade failure of L.P. turbine.
If prime mover with rotor field also fails, alternator will
continue to run but it will damage turbine and generator
rotor as well.In this case the alternator will take active
power and field from grid. The field current will flow
through the surface of rotor through moon slot which will
excessively heat rotor which may damage rotor winding.

Answer / amit pandey

When input to the prime-mover fails, the alternator starts running as a synchronous motor and draws some current from the supply system. This motoring condition is known as "inverted running".

Answer / gms

prime mover decides the operating mode of the machine.
if the prime mover of an alternator fails,motor will start running as a motor..

Answer / thennarasu

hunting problem

PLEASE ANYBODY HAVE ELECTRICAL CIRCUIT DIAGRAM FOR CHMER PULSE CD 60M SPARKING MACHINE.PLEASE MAIL ME SUPRIYAAYYAPPAN@YAHOO.CO.IN.

0 Answers  

---

we have 3 single phase transformers. how will we generate 6 supply from 3 phase supply input

0 Answers   NHPC,

---

What is an Antipumping relay ?

4 Answers  

---

How would your past experience translate into success in this job?

0 Answers  

---

why do you give the dc supply to field of alternator

3 Answers  

---

What test must you do before powering up a circuit that you have been working on?

0 Answers  

---

what is negative d.c. voltage, why this voltage is used in base transciever station.

0 Answers   Vintage Air,

---

How induction stove works?

1 Answers  

---

What is the role of Dedicated earthing in UPS System?

0 Answers   HCL, MSPL,

---

how hazordious area is classified at an oil & gas plant and categorise suitable class of electric equipment in that area like induction motors, LCS, Lighting Fixtures Fluerescent/Flood lights Mercury& sodium lights, J.Bs, Power Cables etc

0 Answers  

---

We have three 33kv substations. All of them energised by same source.When i am checking the phase sequence between one substation to other substation (like R Phase to R Phase) by multimeter i am getting some voltage.Near to LT panels UPS panels are there. Can u explain whether any possible to happen like that. In Phase SEquencemeter is showing correctly in both substations. How is it happen. Explain me.Explain me communication signal will produce Phase difference on this case.

3 Answers  

---

pls tel me the electric train traction motors name plate details like rpm,torue,voltage,amps,watts..ect..

0 Answers  

---