I have a situation where the primary fuses to a single phase transformer are blowing periodically at power up. I have a single phase transformer, 480 volt pri. to 240 volt sec. at 5kva rating.
With no load connected to the secondary, the 2- 10 amp, bussman LP-CC time delay fuses will blow instantly. I have ruled out the wiring, since I replaced it all(even though I detected no problem with it).
That leaves me with only the transformer in the circuit. Since the secondary is also fused, the code allows for an increase in primary fuse size. I installed 15 amp fuses and they blew as well. I now have 20 amp fuses in and so far, no problem.
What am I seeing with this transformer when power is applied? This situation is happening on 2 brand new installations.
With no load connected to the secondary, the 2- 10 amp, bussman LP-CC time delay fuses will blow instantly. I have ruled out the wiring, since I replaced it all(even though I detected no problem with it).
That leaves me with only the transformer in the circuit. Since the secondary is also fused, the code allows for an increase in primary fuse size. I installed 15 amp fuses and they blew as well. I now have 20 amp fuses in and so far, no problem.
What am I seeing with this transformer when power is applied? This situation is happening on 2 brand new installations.