230v 40 amp compressor

#8 wire for a 40 amp breaker is fine for what you have. You could put a 45 in if you wanted to and #8 wire would still be fine.

Some motors will work with 120 volt or
240 volt

You have to remove the small cover on the
end of the motor & see if there is a diagram,
where you move the wires for different voltages

You can contact WW Grainger
Dayton manufacturing is owned by WW Grainger
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=1TMY6&op=search&Ntt=1TMY6&N=0&GlobalSearch=true&sst=subset

Contact Grainger 1-800-323-0600
They will have wiring information for each of their products.

The wiring diagram should appear on side of unit.
This 1.5 Hp motor can be wired for 115 or 230 volts

My AO Smith manual would not be specific to your motor.
With AO Smith 115-230V, there are one set of wiring terminals for incoming wires from breaker box. The other wires connect to terminals.
Copy following illustration link:
http://waterheatertimer.org/images/Motor-wiring-500.jpg

Wire and breaker size:
For 120Volt, use 20 amp breaker and 12 gauge wire up to 25 feet.
Over 25 feet up to 100 feet, use 30 amp breaker and 10 gauge wire.
100-150 feet use 8 gauge wire and 40 amp breaker.
150-200 feet use 6 gauge wire and 50 Amp breaker.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Does it trip the breaker or does the motor just hum and not turn the compressor? The motor may need a start capacitor. Do not keep tryin to start you can burn out the start winding on the motor.
TURN OFF POWER AND LOCK OUT.... try and take the belts off (if it has belts)of the motor and compressor and make sure both turn freely. IF THEY TURN FREELY THERE IS A PROBLEM WITH THE MOTOR. You said voltage, wire size and breakers are the right size.
Hope this helps you with your problem...Jim...please leave a comment

Sounds like the unit is pulling to many amps during start up. Possibilities are: breaker under sized, wire under sized, to long of a run of wire from breaker for wire size,Tank check valve bad. I would check the amps during start up and while running and compare to motor name plate information. Remember at start up the motor may pull 1.5 to 2 times the rated amps on the name plate. Also if this unit has a magnetic starter wire connections may be loose or overloads to small.

Must be your breaker amp must be below requirement. Do not use an extension cable, make it short as possible to the source. It would also be better if you have a separate breaker switch just for your compressor in the panel box.

Our 2 HP Speedaire horizontal tank compressor is rated 115 / 230 volts at 24 / 12 amps, respectively. This means at 115 volts, a 30 amp circuit breaker is the bare minimum. That also means that the wiring should be #10 copper wires for short runs, but the next size up; #8 copper wires would be better connected to a 40 amp circuit breaker. Running at 230 drops the amperage requirement by half, to 12. A #14 copper wire is minimum for short runs with a double pole 15 amp circuit breaker, but #12 copper wires connected to a double pole 20 amp circuit breaker would be better choice.

If the compressor is cord connected (or even directly wired) with the minimum sized wires, it will likely a voltage drop problem unless very close to the panel. This problem is more pronounced as the distance between the circuit breaker and motor increases, or when smaller wires are in the circuit. All the voltage at the circuit breaker does not reach the motor, as it is lost as heat; so the compressor only sees 90 to 105 volts instead of the 115 volts it expects.

If the cords, connections, etc are getting hot, it is a tell tale sign of under-sized wires and /or poor connections. Once you solve these problems, the compressor should run "as advertised " because motors usually don't "go bad" but fail all at once. Unless you have a bearing problem - or there is a problem with the load itself (compressor).

I hope this helped.

hello, if you also have 230V in sweden then look at your electronic supplier for a: Input AC 230V/50Hz/90mA/21VA Output: AC 22V/520mA/11,4VA
that's written on the charger.

A #10AWG wire can be use and 40Amp breaker can be use also. Your 5hp/230V/1/60hz motor amp is 30A.

Diagram for aosmith motor b381 is here: http://www.electricmotorwarehouse.com/IMAGES/B381_connection.htm

However, I believe that this motor will be more efficient at 230v depending on load conditions. At 115v this motor will draw more amps and tend to run hot, but situation rules. Enjoy