hi,

I need to design a circuit to control the speed of a jacuzzi motor. The motor picture is below:



Though I'm a electronic engineer I do not know much about motors and am hence unable to identify the type of motor.

So could someone firstly help me to identify the type of motor?

Secondly, are there any regular circuits which can be used to control this type of motors?

Would be highly obliged if someone could explain the principle behind it too.

Thanks

 

How about a picture of that plate on top - the one with the useful numbers?

 

Priamrules'
Hello. Your motor is probably a 3/4 horsepower impeller motor. Look at the label on the box on top, the manufacturer's name should be on there.
If you are looking to reduce the speed of the motor, good luck. Unless there is a matching speed control from the manufacturer, the warranty will be void. Most Jacuzzis are controlled by valves, or the "eyes" on the rim of the tank, or, tub. Impeller motors, as opposed to propeller motors, work by "scooping" up a fluid thereby creating a void, or vacuum, siphoning the fluid. Decreasing the speed of an impeller motor only slows the siphoning process, which is necessary to keep the fluid flowing, while not introducing air into the system thereby causing an increased demand for the motor to be constantly monitored. Simple jet eyes will take care of this problem. Or lenghten the hose for non-variable, constant regulation.
Dan

 

The only pool/jacuzzi motors I've seen are capacitive start induction motors that run on 60Hz. You can't change the speed of the motor without changing the basic design of it. If you tried reducing the frequency, you'd burn up the motor's windings.

Were it a brushed motor, you could alter the speed, but you would lose quite a bit in efficiency and reliability.

 

The hot tub I once had, had a pump that looked like that one in your picture. However it was a 2 speed motor that was activated by a simple air switch at the tub. The air switch would sequence the a switching relay that would switch the motor windings to select the two different speeds and of course off. There is no simple or inexpensive ways to obtain variable speed with most normal AC induction motors.