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Hello, it does seem to be a problem. Under-sizing the breaker is not a good idea due to nuisance tripping from inrush current although with this being an elevator motor, is it not controlled by a VFD to decrease inrush and starting torque?
You don't have a distribution panel that you could run the transformer feed from?
What is the service size? Is this the main distribution for the building?
I would say your only option is new run from the main 1200 or call the people back and have them install the correct motor/system
You would need to do a load calculation to make sure your existing load and the new motor load won't overload even a 250
and a 250 amp feeder would mean a 400 amp panel.
After 225 amp rated panels the next step is 400
Seems like you're spending a lot of money and time to fix their mistake. Are they paying for this?
No, not a good idea to under-size the transformer breaker and feed. Minimum protection for that transformer is 200 amps. Plus you have the other loads from the panel on a 150 amp feeder.
Do you know the existing load on the panel?
If that adds up to 50 amps or less then it could work. The house panel is 3 phase?
Let me run some calcs for the transformer to see if it needs to be larger than 75 KVA. Do you have the data plate info? Is there a code letter on the plate?
it's a 30 HP with 60 full load amps at 480?
Strange. Do you have a picture of the data plate or the code letter from the data plate?
ok, so the motor is 41 and the controls added to it total 60
You would size the transformer for the motor inrush and operation frequency with more than one start per hour (20% added)
Then add the additional load
You really need the code letter from the data plate on the actual motor to make sure it's accurate. And the impedance from the transformer to make sure. I can forward you the calc sheet I use if you like
You can get it here: https://electrical-engineering-portal.com/download-center/electrical-software/transformer-voltage-size-starting-large-motor
I would use that to calculate for just the motor. Then use normal transformer calcs for the remaining 19 amps then merge the data
225 main sounds like that would be fine.
Glad to help. Let me know if you need further assistance
Yeah. no problem. I will get a notification when you post again