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110v 220v

I am currently building a compressor using a 1.5hp 110/220 volt motor. When started the pressure builds to about 80psi then cuts out at the thermal overload (built into the motor). An electrician friend informs me that the motor overload is more sensitive than the 20 amp breaker, and further suggests either reducing the drive pulley diameter or swap wiring over to

220 volt. My concern is that if the overload trips while wired for 110 v the same would happen at 220v as the effort required to turn the compressor over is bordering on the 1.5hp motors rated capacity.Any help would be appreciated.
Reply to
mjh
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Try another pulley, smaller on the motor or bigger on the compressor. Swapping to 240v probably won't do a thing. I had the same thing when I was making up a compressor. I ended up at almost

10:1 on my pulleys but YMMV depending on the displacement of the compressor itself.
Reply to
Gfretwell

Now I would have thought just the opposite. If you put a smaller pulley on the motor, then you have more torque, that is true. But you're turning the compressor faster and that takes more horsepower (compressing air faster).

While a larger pulley will lower the torque available to the compressor, it will turn slower and take less horsepower.

Hmmm... go figure....

daestrom

Reply to
daestrom

.>If you put a smaller pulley on

A small pulley on the motor and a big one on the compressor makes the compressor go slower ... with higher torque. You pay for torque with speed. It will slow down the CFM for a given displacement (at given pressure) but that is why they make bigger motors :-)

Reply to
Gfretwell

If you are tripping the overload under load, the motor is not sized right for the job. It could be the pully size is wrong or the supply voltage is low under load. John

Reply to
jriegle

OOPS!!! That was my mistake. Oh well, first mistake I made today ;-)

daestrom

Reply to
daestrom

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