Why does inductive loads consume kvars?

Answered by: sinhasunilk on: Jul 3rd, 2010

Electrical load is of three types: Inductive load, Resistive load and Capacitive load.The power drawn in a circuit will depend on type of load, the power is supplied. The circuit which has i...

Transformer signal

What is the benefit of using AC signal in a transformer?

Member Since Jul-2010 | Answered On : Jul 3rd, 2010

Transformer can only operate with A.C supply. Voltage will induce in the secondary winding of transformer only when there is a change in flux. The induced voltage in the secondary winding is no. of turns in secondary x rate of change of flux. In D.C circuit the rate opf change of flux is Zero, hence induced voltage in secondary winding is Zero and no Back MMF produce in the magnetic circuit of core of transformer. This will result in very high current drawal in the primary winding and will result in burning of primary winding of transformer. We can not think of applying D.C source in transformer.

Answered by: SURAJTHEGREAT on: May 5th, 2012

The reason why dc signal cannot applied to a transformer is that f=0,reluctance is 0,very high current flows through windings and it is burnt out!

Answered by: sinhasunilk on: Jul 3rd, 2010

Transformer can only operate with A.C supply. Voltage will induce in the secondary winding of transformer only when there is a change in flux. The induced voltage in the secondary winding is no. of tu...

Transformer oc test

Why oc test is conducted on low voltage side?

Answered by: A.santosh on: Jan 26th, 2012

If want to conduct OC test on HV side we need more turns of auto-transformer, as an engineers we should have to decrease the cost required for the test, so normally OC test is conducted on LV side since we need less turns of auto-transformer

Answered by: sinhasunilk on: Jul 12th, 2010

Voltage injection in LV side is convenient, The cable attached to LV side also need insulation suitable to LV voltage rating. If LV ia in the range of 440V and HV is of the range of 11KV, we may inject voltage in steps also through variac of 440V , Which is not possible if inject voltage in HV side.

Insulation resistance testing

When we apply the DC voltage thro' the digital megger to test the ir value for cable/motor winding etc., we can see the digital display of the test equipment showing more than the applied voltage (for eg. If we select 500v dc, we can see 526v DC in the display) why?

Answered by: sinhasunilk on: Jul 3rd, 2010

When we measure IR value, we measure resistance of insulation of the circuit either w.r.t earth or w.r.t. to other phase.The digital display is resistance between the ckt and earth, not the voltage. I...

Alternator

Why alternator is operated at lagging power factor? how alternator responses with changing the load?

Answered by: sinhasunilk on: Jul 3rd, 2010

The Alternator has very little margin to run in the leading P.F. so far electrical stability of alternator is concered. If we operate generator at higher leading P.F. machine will become uns...

Answered by: rajakumar1985 on: Sep 9th, 2009

Since the Synchronous generator having the property of supplying the reactive power along with the real power, this can be operated in lagging power factor only. Suppose if it want to work with leadin...

Power distribution

Answered by: sinhasunilk on: Jul 12th, 2010

Load is represented in KW. Whether it is single phase or thre phase, same load is to be supplied. You have asked the conversion of 100KW single load to 3 phase load. In three phase equvalent load will...

Insulation value

What is the thumb rule for insulation value in bus bars, phase to phase and phase to earth for 11 & 33 kv system?

Answered by: sinhasunilk on: Jul 3rd, 2010

It should be at least KV+1 at 40 degree celcius.