3
\$\begingroup\$

I'm building a machine to help me manufacture some optical components more quickly. The machine will be powered by a plain old, "boring" 1/4 HP motor, like the ones used for various household appliances. I actually bought this one:

http://www.amazon.com/gp/product/B006P1RUOM/

The product description says: "split phase motor, 5.4 amps, 60 hertz, auto protector". The page title in case the link is dead: "A.O. Smith GF2024 1/4 hp, 1725 RPM, 115 volts, 48/56 Frame, ODP, Sleeve Bearing Belt Drive Blower Motor".

How would you choose the circuit breaker for this thing? I assume it will have to support a current larger than the stated 5.4 amps, because there's an initial shock when you power it on.

For extra safety I would prefer a 2 pole breaker. The optical items are coated with some water-based fluid during processing and, while there's no chance for the fluid to reach the inside of the box, where the motor is, I am very much in favor of taking additional safety measures whenever it's reasonably possible.

\$\endgroup\$
2
\$\begingroup\$

Due to the environment, it sounds like you need one of these (Residual current detector): -

enter image description here

This detects a difference in current between the two AC wires and trips the contacts breaking the circuit. It also has fuses for overloads and you may consider that this is enough protection.

| improve this answer | |
\$\endgroup\$
1
\$\begingroup\$

Assuming because you are using 115V this is going to be used in North America.

2 pole circuit breaker for 115V is pointless, it does nothing for you.

You cannot connect this in the field with wire less than 14ga, so a 15A circuit breaker is fine. The motor has it's own protection built-in.

If the environment is wet, you will be required to use a GFCI (North American version of the RCD mentioned above). You may experience nuisance tripping however. Better to design the system to no allow exposure to moisture.

| improve this answer | |
\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.