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New to me lathe. motor can be wired 240 or 480. I'm switching from 480 to 240.

thickanvil69

Plastic
Joined
Nov 10, 2021
I have to motor re wired but I can't get it to turn on I'm getting some buzzing in the relays. Wondering if I need to re wire the transformer. It's also says it's 480 and 240 3 phase. But I don't have a diagram for that. Any insight would be great.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Do you have 240v 3 phase power? Yes, the transformer will need to be re-wired, there is usually a diagram on them. You will also need to replace the heaters on the mag contactors as your amperage at 240v is twice the amperage of 480v.
 

thickanvil69

Plastic
Joined
Nov 10, 2021
Is there any way I can post pictures on here to show you what I have going on. There's a diagram on the cover but I'm having trouble making heads or tails of it
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Do a search for part# on the transformer and see if you can find a diagram. Same for heater part#, find amp specs, never know, they might already be sized for 240v, might not. Look at motor data tag to figure out amperage on 240V.
 

Grigg

Hot Rolled
Joined
Jun 25, 2007
Location
Lexington, VA
To size the heaters you need the motor nameplate amps at the intended voltage, then look at the chart you show posted inside the electrical cabinet. Pick the heater that covers or is closest to the motor nameplate amps, or follow instructions on that chart if different than what I suggested.

However you need to do a little more digging and considering first before switching to the lower voltage.
Just because the motor can run at a lower voltage doesn't mean the rest of the related stuff in the electrical cabinet is good to go. For example I have a 440V L&S lathe and the motor starters (the whole things, not just heaters) are undersized if running 220V. Similarly you need to evaluate wire size and intended amps if switching from higher to lower voltage. Ideally everything in there is sized for the higher amps that come with the lower voltage, but if they needed to cut cost and knew it was going to be wired for high voltage it may not be safe on lower voltage.

If all that pans out... the transformer is usually to supply control voltage, sometimes also a work light at 110V. Determine what the output voltage should be, then rearrange the input leads or terminals to keep the same output voltage. As mentioned a diagram for the transformer would be helpful, but with a little understanding of transformers and some care you can likely guess and check if it comes to that.

Look for entire machine wiring schematic too, that may be helpful.
 








 
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