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460 volt to 230 volt?

comp 670

Aluminum
Joined
Mar 5, 2016
Hi, I have a opportunity to buy a press brake and shear for my shop but they are both 460 volt 3 phase and my shop only has 230 volt three phase. What are my options for converting or running these in my shop? Change out the pump motors or get a transformer?
Thanks.
 
First question, are they dual voltage motors? Look at the data plates, if they show both 460 and 230 with amperage ratings for both, they can be reconnected for the lower voltage.

You will have to change the current sensors or thermal units in the overload relays, because half the voltage means twice the current.

An additional problem will be, assuming NEMA style motor starters, the existing motor starters may be too small for the new amperage rating required by the lower voltage. Get the data from the starter plates and report back, please.

Dennis
 
First question, are they dual voltage motors? Look at the data plates, if they show both 460 and 230 with amperage ratings for both, they can be reconnected for the lower voltage.

You will have to change the current sensors or thermal units in the overload relays, because half the voltage means twice the current.

An additional problem will be, assuming NEMA style motor starters, the existing motor starters may be too small for the new amperage rating required by the lower voltage. Get the data from the starter plates and report back, please.

Dennis
All good advice, and if it turns out that you must replace the starters, breakers etc., the transformer option begins to look better and better. If the motors are starting Across-the-Line (as opposed to a soft starter or VFD), the transformer kVA should be at least 2x the motor HP, 3x is better. So for example if the motors are 5HP and 2HP, get a 15kVA transformer as minimum, 22.5kVA if you can find one cheap enough.
 








 
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