Two 240 to 480 transformers

[Tom Kitta]

Smaller one $40, bigger $70 OBO

 

[slow-poke]

Great deal if you need them, and big enough for most hobby sized equipment.

 

[buckbrush]

Is there a chance you have a 240-600 transformer for sale?

 

[Tom Kitta]

Sorry, no. But maybe you could try to run the 480v a bit hotter - don't know. I would not have issues running 550v motor on 480v or 500v.

 

[slow-poke]

600V on a 480V transformer would overexcite the core, not recommended. Lower is okay.

 

[Tom Kitta]

600V on a 480V transformer would overexcite the core, not recommended. Lower is okay.

I was thinking of taps on the 480v transformer - there may be some to adjust the voltage up. I made my own taps on a 600v transformer to go down in voltage.

I actually run my motors at +10% voltage as both transformers I have are 480v and 600v while motors are rated at 440v and 550v. No issues - same as if I run them on the lower voltage at -10%. You only would have issues close to full load where low voltage decreases power (and increases heat) and high voltage increases heat. Actually even with high voltage only ambient max temp would drop by 5 degrees.... realistically for home shop +-10% is totally fine.

I run 440v motor on 240v and that was an issue - it was severely underpowered but did start and run at full speed - no overheating (!)

In case you are wondering why I don't get rid of 600v transformer and just run 480v on everything, my transformers are 240 --> 600 and 600 --> 480 both 3ph.