Transformer blows primary fuses with no load.
Transformer blows primary fuses with no load.
(OP)
We have a 5000 kva transformer wired 480 volt on the primary and 230 volt on the secondary. This is a single phase transformer. When you power it up three to four times it blows the both primary fuses. What do you think is the problem.
Thanks,
RogerMM
Thanks,
RogerMM






RE: Transformer blows primary fuses with no load.
Can you change primary taps so you get less V/turns? That usually means changing to a lower secondary voltage and improves the situation a lot.
Did you say 5000 kVA? Single phase?
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.
Transformer inrush seems the likely culprit, I agree with the others.
Inrush current can vary significantly depending on instantaneous value of the voltage (voltage phase angle) when the transformer is energized. So often, this type of fuse blowing occurs maybe one time out of 5 or one time out of 10.
If you can confirm the transformer size, maybe we can make some suggestions on the fuse size.
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.
Are you trying to protect anything thermally with the fuses? Don't. Use fuses only as a short circuit protection. And use slow blow fuses.
If you are using fuses like 16 or 20 A, then they shall blow occasionally. Use something like 35 A.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Transformer blows primary fuses with no load.
THANKS,
ROGERMM
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Transformer blows primary fuses with no load.
#10 is good for 30A max.
RE: Transformer blows primary fuses with no load.
Thanks for your thoughts on loaded transformer.
RE: Transformer blows primary fuses with no load.
RE: Transformer blows primary fuses with no load.