7379df
New member
- Location
- Branson, MO
I have a Primary 480 volt delta to Secondary 240 volt delta transformer and wanting to reverse wire this unit where my incoming 240 volt three phase, will step up to 440 or 480 volt to run a 1 HP motor. This is for my personal shop not a commercial application. On that note. I know it is not recommended to reverse wire transformers that are not designed for this. Again this set up is Not being used in our commercial shop. In my place of work we have a 20,000 pound sander that that runs on 480 volt. Plant voltage is only 240 3 phase High leg Delta or Open Delta. We used a 200 kva transformer that was used to step down 480 volt to 240 volt and reversed wired. The sander had a breaker that was 200 amp on 480. So we doubled size of breaker to 400 amp 240 volt in a separate panel. This machine has been in service now for 5 years and going strong. No problems what so ever. Im not sure exactly what the transformer was that we used, a delta or wye. So back to my question is I got the transformer (75 kva) which is way bigger than I need for a 1 HP motor but looking at adding other 480 volt equipment later, I proceed to hook up by simply connecting 240 line voltage to primary side and and test just using a 20 amp 3 phase breaker to see if I had 480 volt on secondary. (Just like we did the above mentioned larger transformer) To my surprise the breaker immediately tripped. So I disconnected the ground completely and tried again. Still not luck. So im sure there is more to this than meets the eye... as always appreciate any comments or info regarding this. Thanks.
Also was going to try and send a schematic that came with transformer
Also was going to try and send a schematic that came with transformer
