Interested to Buy Any Domain ? << Click Here >> for more details...
What core magnetic balance test of transformer?
How to do this test in a three phase Star delta (star-LV,
Delta-HV) transformer?
How to measure and where to measure?
thanks and regards
Austin
- 22 Answers
- 101142 Views
- Neutech, Power Grid, TSSPDCL, I also Faced
- E-Mail Answers
Answer Posted / engr. ziaul ashraf shafi
Answer #5 is fine.. but i want to add something more..
normally this test is made in star side of the transformer.
the result should be varified like following:
1) if 2u-2n is fed by 230 volt.
- the nearest phase (2v-2n) will experience the 85% to 90%
of fed voltage at 2u-2n. (i mean 2v-2n = 195.5 to 207
volt). And the distant phase (2w-2n) will experience the
10% to 15% of fed voltage at 2u-2n. (i mean 2w-2n = 23 to
34.5 volt).
2) if 2v-2n is fed by 230 volt.
- then the fed pahase is middle phase, and both other phase
are magnetically in equal distance.. so the measured
voltages in 2u-2n or 2w-2n = 50 % (or 40 to 60 % is also
accaptable). so the 2u-2n or 2w-2n = 92v to 138v is
accaptable.
3) if 2w-2n is fed by 230 volt.
- the nearest phase (2v-2n) will experience the 85% to 90%
of fed voltage at 2w-2n. (i mean 2v-2n = 195.5 to 207
volt). And the distant phase (2u-2n) will experience the
10% to 15% of fed voltage at 2u-2n. (i mean 2w-2n = 23 to
34.5 volt).
*If the results are found beyond these above mentioned
limits then other tests (like open ckt test with rated
voltage) should be performed to be sure about core and
winding.
*You can measure and note down the current of each injected
phase. it will give u a signaficant idea about winding. if
the winding has an inter-tern short then the faulty phase
will draw comapretively large magnetizing current like 3A
or 5A, wheather other phases will draw 60mA to 100mA.
*Remember, the magnetic reluctance path of a core is not
lenier, so the result veries itself. But big differences
are remarkable.
*Sometime due to non-lenier characteristic of magnatic
circuit and the presense of harmonics in the fluxes of un-
excited phases, the algebric sum of induced volage in two
phases may not be equal to the applied voltage.
*if there is a turn to turn fault in any phase winding, the
faulty section will draw comparetively large magnatizing
current which will oppose the magnetic fluxes and will
result a very low induced voltage (tends to zero) in the
faulty phase.
*this test should be performed after demagnaizing the
transformer properly. slightly magnatized transformer (like
after insulation test) can give you an unexpacted and
distorted result of magnetic balance test.
| Is This Answer Correct ? | 73 Yes | 3 No |
Post New Answer View All Answers
what is gas turbine intercooling ?
Does all the output contacts (N/O as well as N/C) of a Numerical relay operate when relay receives a binary input/inputs or contacts are designated to specific logic input/inputs and only these contacts operate?
What are the disadvantages of autotransformer?
Why Transformer Neutral having one earth pit ( more earth electrode resistance) whereas body have many earth pit ( less earth electrode resistance)?
TYPE'S OF BREKAR ,WHAT IS TRANSFORMAR & SAFTY. STARTER DOL & STAR DELTA STARTER.
How does "OUT OF STEP" relay ,for Synchronous motor protection, work?
can you send me the placement papers of electrical engg. from companis like NTPC,DRDO,IOCL,HPCL,BPCL etc.?If,plz send as soon as possible.Thanks.
what will happen when the dc supply is given to the capacitor?
What are the advantages of hydropower?
sir please tel me how calucalte kwh if home taken load 30ams how maney kwh taken per day.and 3phase motor 5hp per hars how maney load teken and how mach kwh and forward me to electrical table for calicalte kwh and kvr and kvah
Any one who apply for Ferro Scrap Nigam Limited cn join with me at rajuhalder@indiatimes.com or 09669717028
5- What is the task (function) of the excitation and isolation transformers in power plant? 6- What is the task (function) of LCI (A), LCI (B) and LCI (COS) in power plant? : LCI (A) and LCI(B) are load commutating inverter for generator turbine starting. , LCI (COS) is load commutating inverter change over switch
what is value of Jin transformer
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
How to distinguish whether MCB is DC or AC looking at it physically
