The XFMR nameplate should have temperature rise information on it. I would look there first. Also, if memory serves me, the nameplate temperature is the max safe "rise" temperature ABOVE ambient.
I don't know if you could use it or not, but, Harbor Freight sells a tool magnetizer/demagnetizer that may do the trick. FYI, I have no affiliation with Harbor Freight, just infatuation lol. It's probably just a magnet, but it may be worth a try for just a few bucks.
Thank you for the reply. I understand that there are two zig zag options. Could you elaborate on the advantages/disadvantages of each? Are the double delta and both zig zag configurations balanced? Are the power outputs the same? I have searched for hours and can't find what I'm looking for...
Gentlemen, I have been searching for information related to operating a 12 wire generator for single phase. I've found wiring diagrams but I can't find anything on the advantages/disadvantages of the different methods. I am specifically interested in power output and load balancing. Does anyone...
Understood. I get the vector addition. What I'm having a hard time understanding is why the center point of your vector diagram wouldn't shift when you removed one of the phases. I imagine in my head,(dangerous in there) three rubber bands being pulled by equal magnitudes(139V) in equidistant...
That makes perfect sense Bill. So, would that mean that I would have roughly 278V across the two legs if I connected it in the configuration I mentioned? I'm not going to do this, I just want to make sure I follow...
Gentlemen, I have attached a photo of the XFMR in question. The primary of the XFMR is Nominal 550V Delta. Our plant voltage is roughly 580V on all 3 phases. The secondary of the XFMR is 240Y/139V. We are only using two legs of the Y on the secondary. All secondary loads are from phase to...
I would connect the motor for 400V to give you the 10% in each direction. If you go with 380V, it may go above 10% on the high end. If you go with 415V, it may go below 10% on the low end.
I am an engineer, so the glass is twice as big as it needs to be.
Hello, I just received an email from a customer having issues with a piece of mining switchgear. This unit has a 2750 KVA XFMR with a delta 13.8 KV primary, a delta 2.3 KV secondary @ 2000 KVA, and a wye 480 V secondary @ 750 KVA. The secondaries both feed busses. The 2.3 KV bus supplies...
What kind of CT configuration are you using? Is it truely residual? You may want to go to a zero sequence current sensing CT. You may also want to look into the residual properties of the relay that is tripping (if your sensing is truely residual). I have ran into problems when the manufacturer...
As of yet I have been unable to aquire the ratings of the surge arresters. I was assigned damage assesment of the fault and I haven't been able to speak with any of the engineers since I was on site. Even if the 995V surge arresters were inadequate, shouldn't the 4160V arresters have taken...
I have recently been introduced to Transient Recovery Voltage issues when a vacuum contactor clears a fault. We had a failure of some lightning arresters in the field and some of the engineers think that it is a TRV issue. I have a basic understanding of what occurs when a vacuum contactor...
