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There is a need to power a battery charger, which requires 3 ph 480V 20A circuit. There is no 480V available at this location, however there's an electrical panel 120/240V where 3 ph 240V is available. Loads in that panel are connected by 100A breaker (installed inside the panel). There was a suggestion from managment to use power from that panel and a 45kVA transformer which we already have. This is wye (H) to delta (X) configuration.
I have quite many objections against this idea, like for example:
  • high inrush current may be tripping breakers when the transformer is being switched on
  • the transformer seems to be grossly oversized for that application, but considering that charger may represent highly non-linear load, the transformer will be overheating anyway from harmonics.
I can do the following:
  • convince management to hire external electrical company to do the installation
  • try to do it on my own, ignoring the fact that I have much more background in electronics and automation than electrical installations. But here, in the USA, energy and enthusiasm sometimes counts more than knowledge and experience, as I have noticed.
Any suggestions? Or recommended literature on industrial electrical installations?
 
There is a need to power a battery charger, which requires 3 ph 480V 20A circuit. There is no 480V available at this location, however there's an electrical panel 120/240V where 3 ph 240V is available. Loads in that panel are connected by 100A breaker (installed inside the panel). There was a suggestion from managment to use power from that panel and a 45kVA transformer which we already have. This is wye (H) to delta (X) configuration.
I have quite many objections against this idea, like for example:
  • high inrush current may be tripping breakers when the transformer is being switched on
  • the transformer seems to be grossly oversized for that application, but considering that charger may represent highly non-linear load, the transformer will be overheating anyway from harmonics.
I can do the following:
  • convince management to hire external electrical company to do the installation
  • try to do it on my own, ignoring the fact that I have much more background in electronics and automation than electrical installations. But here, in the USA, energy and enthusiasm sometimes counts more than knowledge and experience, as I have noticed.
Any suggestions? Or recommended literature on industrial electrical installations?
I did a little math and it would take 100 amp breaker and I’m like you if you work in a manufacturing plant I don’t see no reason that they wouldn’t change the voltage. Yes the 45k transformer if it’s 240vac 3 phase wye primary to 480vac 3 phase delta connection. I don’t think it will start tripping breakers and I wouldn’t worry to much about harmonics, just don’t use it for lighting. Good luck
 
There is a need to power a battery charger, which requires 3 ph 480V 20A circuit. There is no 480V available at this location, however there's an electrical panel 120/240V where 3 ph 240V is available. Loads in that panel are connected by 100A breaker (installed inside the panel). There was a suggestion from managment to use power from that panel and a 45kVA transformer which we already have. This is wye (H) to delta (X) configuration.
I have quite many objections against this idea, like for example:
  • high inrush current may be tripping breakers when the transformer is being switched on
  • the transformer seems to be grossly oversized for that application, but considering that charger may represent highly non-linear load, the transformer will be overheating anyway from harmonics.
I can do the following:
  • convince management to hire external electrical company to do the installation
  • try to do it on my own, ignoring the fact that I have much more background in electronics and automation than electrical installations. But here, in the USA, energy and enthusiasm sometimes counts more than knowledge and experience, as I have noticed.
Any suggestions? Or recommended literature on industrial electrical installations?
Papa big companies always does stupid ---- but they ought to take in to consideration that you are the electrician and they should let you advise them. I’ve worked in many plants and they bought this machine and they want it running so all you can do is go ahead and use the 45k transformer and see what happens.
 

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