Question { 6436 }

Why servomotor and induction motor are in different shape

Answer

Induction motor Forced cooling ( Fan )
Servomotor Natural cooling.
Also servomotor having two terminal.
1. power terminal
2. Feedback terminal

Question { TATA, 12682 }

Can anyone explain how the vector diagram of a transformer
which doesn't have name plate be found whether it is
Dy11/Dy5/Yd11 and so on?

Answer

Yah! can.
If Dy11
Primary winding having only 3 terminals with high
resistance and secondary havign 4 terminals with low
resistance.

If Yd11
Primary having 4 terminals with high resistance and
secondary having 3 terminals with low resistance.

If Dy5
This is not a verctor group.

Eppdi???

Question { HSL, 12420 }

why neutral can not used in three phase motor connection?

Answer

No need to use neutral connection in three phase motor
connection.
1. If the motor conneciton is in Delta only three phase can
connect.
2. If the motor connection is in Star the star point
(shoted point ) act as a neutral. (krichaffs current law)
So no need to connect the neutral.

Question { 9147 }

what happen if position of GNA and MNA is changed in
machine?

Answer

There is voltage drop due to armature reaction may happen

Question { Apollo Power, 80123 }

what are the main parts of DG? explian thier functions?

Answer

A normal DG (Diesel Generator ) having two parts.
1. Engine
2. Alternator.

The engine is a pimemover of the alternator. The engine is
started by using DC start motor.Following attachments are
fitted with engine.
1.Self start arrengemnt.
2.Radiator arrengment.
3.Air filter.
4.Lub oil arrengement.

The second one is alternator which is convert mechanical
power into electrical power.
Alternator having following arrengemts.
1.AVR (Automatic Voltage Regulator)
2.Startor winding
3.Field winding
4.Rectifier

Normally the DG capacity mensioned as in KVA raring.

Question { 30797 }

How current is reduced in STAR connection?

Answer

Initially there is no back emf in motor while starting. If
apply high voltage the motor will draw more current. That
is why the motor always satat with star connection.(low
voltage )

Question { NTPC, 13967 }

Why a transformer Noise during its running condition ?

Answer

While giving the ac power to the transformer the core will
compress and elongation. Due to this noise is come.

Question { 7509 }

what is skin effect?

Answer

This effect is in transmision line. Due to inductence of
the solid cable the all currents will go in outer side of
the cable (skin). To prevent this problem the transmission
cable should be multistrand.

Question { 4866 }

What happen if you keep open the Neutral Grounding Switch
in open condition of the HT Generator at starting and again
on load if it open then?

Answer

If open the neutral grounding switch there will be some
voltage in neutral wire due to unbalance load. And neutal
float will be there. So, dont disconnect the neutral ground.

Question { 5258 }

what will be the difference on output when 3phase I.M. is
given a delta or star supply?

Answer

Thre is many difference.
1. Applied voltage between the each winding.
2. Efficiency of the motor
3. Load current
4. Number of cables between starter and motor