Need to hook-up pond motor 115V , two speed , 3/4 3450 rpm-1/8 1725 rpm , with switch for speed slection.

the side of the motor has a wiring diagram, pictures also help us fixya guys help u

I'm going to take a guess and say you are dropping a 230v motor down to a 115v motor.
If the original motor on your equipment was 3 phase, then you need to change motors.
On the other hand, if the equipment had a 230v single phase and you are switching the motor wires so you can plug the equipment into an available 115v outlet, then I would suggest reconsidering. I would recommend running a 220v service line to your equipment instead. It will save on your electric bill and the motor will last longer. A 115v motor pulls twice as much amperage as the same motor running on 230v. (it may even be too much for the 115v outlet you are planing on using) Your variable rate electric meter will tell your power company to up the rate you pay per kilowatt-hour when you use power at a lower voltage but higher amperage rate.

That said, you need to make sure that the coil in your fancy starter switch is a 115v coil. (it probably is) When you hook up the 115v plug, you need to make sure that the black wire in the Starter Switch is the wire that the switch borrows power from to kick start the magnet that keeps the circuit closed. Beyond that , you probably don't have to do anything in the switch. If there's a red wire, you can just disconnect it and tape it off and do the same in the plug.

If the a10ago's function is a mystery, it will help to understand how it works:
Basically, the contactor has three switches side by side. Where the power comes into the box, there's what looks like a lot of extra screws. That's where the thermal protector is (circuit breaker) that will protect your motor at the proper level designed for the motor. The switch has a spring that holds it open so the motor won't run. But there's an electro magnet that can hold the circuit closed. That magnet is only energized when the switch is closed because even though one of its leads is connected to the hot side of the switch, the other lead is connected past the contactor which has no power when the switch is off.
Your 'START' push button momentarily energizes the coil (or maybe it just overpowers the spring and physically pushes the switch closed). The switch closes and the motor runs and keeps running because the coil is energized. Your 'STOP' button momentarily cuts current to the coil and the switch pops open.
The purpose of this contraption is:
1. It contains a circuit breaker suited for just the motor that is running, not for every load on the circuit.
2. It has contacts that will wear much longer than a standard switch.
3. If your shop loses power with the motor running and then the power comes back on later, your motor wont start running by itself. It will wait until you press the 'START' button.

This is usually caused when the motor sits awhile w/o being used. Remove the rear cover with a flat blade screwdriver or 1/4" nut driver. using a flat screwdriver, spin the armature clockwise. this should fix it. If you cannot spin it, the motor should be replaced.

You have two windings if it is two speed. What you need is a switch
before your wires come into the motor you need to take one of the leads and run it through a high low switch. This will simply take one of your 110v lines and make it go to high and low speed on the motor.
Green will go to ground, one 110v line will go to common and the other goes to the switch. It comes out as two leads. One will hook up to the low speed terminal and the other will hook to the high speed terminal in the back of the motor.

There should be a wiring diagram on the name plate of the motor, or inside the wiring compartment or on that cover . Would be something with dots and HI , LO, and wire numbers.. or just a notation of 120 , 220 volts.
How is it wired now?

Some motors have two speeds listed on the spec plate, study the wiring diagram on the plate to see if the speed is set by the way you wire it.(which leads you twist together at the motor)Good luck

no . with out getting to complicated the motor is designed to operate at 60hz witch is the frequency the voltage is delevered to you at. A dimmer switch changes voltage (lowering voltage it dims your lights) lowering the voltage to a motor will raise the current (amps) create heat and kill the motor and probable the switch. Good news is you can purchase fairly cheap VF (variable frequency) drives that will do what ever you want word of caution running a motor at 30Hz or less (half speed) the motor will probably require an additonal cooling fan since its internal fan will be turning to slow to be effective
good luck

call grainger's technical service department they can help and fax you a wiring diagram

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