C
I have a old detroit diesel. 4160 VAC, 2500 kVA output through 15 kV stepup transformer. Inspectors recently found problems with the pad mounted switchgear. S&C PHM-12. Must replace switchgear with new PMH-9.
PMH-9 arrived with no fuses. I have been tasked with sizing the proper fuses. I read everything I can find, yet I am still confused.
I started the diesel and synchronized and proceed to full load. I recorded 4160 Volts and 220 amps. I then applied the math. 4160 X 220 X square root of 3. This math matched generator output on gauges.
If I do a ratio compare to the 15 kV, the a 66 amp fuse is minimum. If I do 125 percent of that then 82 fuse is needed.
My problem is the fuse will be on the primary side of the transformer and I am having problems reversing the math to protect the transformer and underground cabling.
Any 3 phase for dummys stuff would be appreciated.
PMH-9 arrived with no fuses. I have been tasked with sizing the proper fuses. I read everything I can find, yet I am still confused.
I started the diesel and synchronized and proceed to full load. I recorded 4160 Volts and 220 amps. I then applied the math. 4160 X 220 X square root of 3. This math matched generator output on gauges.
If I do a ratio compare to the 15 kV, the a 66 amp fuse is minimum. If I do 125 percent of that then 82 fuse is needed.
My problem is the fuse will be on the primary side of the transformer and I am having problems reversing the math to protect the transformer and underground cabling.
Any 3 phase for dummys stuff would be appreciated.