Transformer Connection

Quote" we had connect the incoming cable to the primary of the transformer. with different phasing. after energizing the transformer."

What do you mean by this statement? Please explain.

hI, wareagle

I mean the incoming is the source 440vac R/Y/B and the primary is the load 440vac.

The incoming R/Y/B connected to the source, which the connection is of the load on the primary is U1/W1/V1.

Call the transformer manufacturer.

....and discuss the <...funny noise...> with them.

Hai

Noisy Transformer

Possible cause = Suggested Remedy

Overload = See "Hot transformer" above

Mtl part ungroundand loose connect = check clamps, cores and parts normally grounded for loose or broken connections, missing bolts or nuts, etc.; tighten loose clamps, bolts, nuts; replace missing ones.

External parts&accessories in resonant vibration = Tighten items as above; in some cases, loosen to relieve pressure causing resonance and install shims

Incipient fault - core or winding = check with Manufacturer

Phase sequence is not correct = Check the phase sequence RYB,UVW it is correct or not

Another possible cause of "funny noise" from a transformer just being switched on could be ferroresonance, if not all 3 phases were turned on or connected simultaneously ("single-phasing"). If you were energizing the transformer using individual single-phase switches or fuses, or one of the switch / circuit breaker poles did not close fully, you could have a phase missing to the transformer. This, together with long (often underground) cables feeding the unloaded transformer, can cause a resonance condition that will usually result in the most ungodly noise coming from the unit.

If you don't have a load that is phase dependent (rotation, etc.), then it doesn't matter for testing purposes if you connect it A-B-C, R-Y-B, W-V-X, or whatever. The transformer takes what you put in and transforms it. It only really matters when you have to get a specific phase rotation for loads and metering that require it, or for matching phasing with other sources (other transformers).

Hi, All

the phase sequence is R/Y/B to U/W/V