Timeline for 75kva three phase 208v delta to three phase 208v y transformer wiring/results?
Current License: CC BY-SA 3.0
20 events
| when toggle format | what | by | license | comment | |
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| Jul 6, 2016 at 17:34 | answer | added | rfkortekaas | timeline score: 1 | |
| Jul 6, 2016 at 15:38 | comment | added | Dan | @Mark, the primary wiring is correct (wired to H1/H2/H3) so the breaker tripping is still a questionable issue. I was almost 100% certain the phase order wouldn’t matter. I tried every possible combination of black/red/blue to H1/H2/H3. There are two combinations that do not trip the breakers (Black-H3/Red-H2/Blue-H1 or Black-H1/Blue-H2/Red-H3). When black is wired to H2 or H3 the breakers trip instantly. Thoughts? | |
| Jul 6, 2016 at 15:30 | history | edited | Dan | CC BY-SA 3.0 |
Corrected terminal numbering/phase color in regards to current test
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| Jul 6, 2016 at 15:13 | comment | added | Dan | @Mark, The measurements are correct. See images. link link link | |
| Jul 6, 2016 at 15:07 | comment | added | Dan | @Mark and Andy aka, thanks for answering the question around the ground/neutral. I figured it would have some voltage (around 1-2volts) but 7 seemed out of the norm. | |
| Jul 6, 2016 at 14:56 | history | edited | Dan | CC BY-SA 3.0 |
Added photos and clarified a few things.
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| Jul 6, 2016 at 10:38 | comment | added | Mark | But the current is odd, assuming you had nothing hooked up to the secondaries. Could it be a measurement problem? | |
| Jul 6, 2016 at 10:37 | comment | added | Mark | The voltage between ground and neutral is fine. They are actually floating with respect to each other, so measuring 7 volts is not surprising. Measuring the hot legs against ground should reflect the same 7 volts (they are also floating), so those voltages are reasonable. | |
| Jul 6, 2016 at 10:34 | comment | added | Mark | One odd thing is that you tripped the breaker at first. The order of the phases really does not matter. There might have been something mis-wired the first time? | |
| Jul 6, 2016 at 7:08 | comment | added | Andy aka | 7 volts between ground and neutral - why are you surprised - there is no connection other than capacitive between primary and secondary so something round about 0V +/- X volts is to be expected. maybe you have left out some information somewhere? | |
| Jul 6, 2016 at 4:26 | comment | added | LShaver | I would edit the question to incorporate all these changes. Also a sketch would be nice... | |
| Jul 6, 2016 at 4:04 | comment | added | Dan | Rereading that and I seem to be rambling on about what I need it for and overlooking the clarity of my answer. Let me try that again. Yes, the delta (primary) side is wired to my building's wye service. It is my understanding that delta devices can be wired to wye by simply disregarding the neutral. the wye (secondary) side is where I have the voltages issues between ground/neutral and between one phase and ground. Hope that clarifies everything. | |
| Jul 6, 2016 at 3:46 | comment | added | Dan | The reason for the transformer to to isolate the neutrals between the two services. When the lights dim we can't have a buzz in the sound system. We need an independent neutral which is where the 208 delta to 208 y comes in. | |
| Jul 6, 2016 at 3:39 | comment | added | Criticizing Israel not allowed | @Dan To clarify what ThreePhaseEel seems to be asking, you connected the delta side of the transformer to your building's Y service, rather than the Y side to the Y service? I don't know much about three-phase power, so maybe that's a reasonable thing to do, but it's at least counter-intuitive. | |
| Jul 6, 2016 at 3:33 | comment | added | Dan | The transformer is 208 delta to 208 Y. My buildings service is 208 Y. Am I correct that you just disregard the neutral when hooking up in delta fashion? We've rented a similar transformer before and that's how it is connected. | |
| Jul 6, 2016 at 3:27 | comment | added | Dan | As someone with 20 years of experiance providing generators and temporary electrical systems for special events, I am not a noob to electrical wiring. I'd just like to know if my results are typical or not. I also think it's important for anyone else installing a transformer to know what typical results are. Many "licensed" electricians have never installed a transformer like this before. | |
| Jul 6, 2016 at 3:23 | comment | added | ThreePhaseEel | Where'd you get a 208V delta from? 208V service is just about always wye -- which means you have the transformer wired wrong, so no wonder your results are fubar :P | |
| Jul 6, 2016 at 2:48 | comment | added | user2943160 | Consulting a licensed electrician is probably the best plan. | |
| Jul 6, 2016 at 2:36 | review | First posts | |||
| Jul 6, 2016 at 2:48 | |||||
| Jul 6, 2016 at 2:33 | history | asked | Dan | CC BY-SA 3.0 |
