Controlling Induction Motor (0.5HP, 115V, 1725/1140 RPM, 7.9A/7.2A, 60Hz cycle)


I’m looking to control the RPM of an induction motor using an Arduino Mega ADK. Any suggestions on how I can do this? Is an arduino the right controller to do this? Would a phidget/beagleboneblack/Pi be better for this? I only have a background in Arduino. It will also have an accelerometer connected, temperature sensor, vibration etc.

Motor Model: 5KH46JR15S

The motor is connected (plugged into) to the wall (120VAC).

Thank you!

induction motors are designed to be synchronous with the supply frequency.

To vary the speed you will need a variable frequency drive.

Thats power electronics.

You might have a chance with a commutated motor though

Oh. Should I just purchase a stepper motor as it better fits this application and is easier to control with an Arduino? I can't see any online that has higher specs than the induction motor that I would use.

step back and define your project. this could be an XY problem in the making.

the motor you referred to appears to be a washing machine motor ?? this would have a lot of wires ???

tell us what you want to do. what is the application ?

there are a lot of different type of AC motors. some, like a sewing machine motor, can be controlled with a very simple speed control. some cannot be controlled with a speed control because the speed is dependant on the frequency.

you have to step out of time for a second. if a motor spins at 1,700 rpm and delivers 1/4 HP the formula uses time as a component. if you change the frequency, the time will change. if you cut the frequency in half, then the speed is 1,700 rp(m*2) and will deliver 1/4 hp per minute/2 or 1/8 hp per minute at half speed.

you still get 1/4, but now it takes 2 minutes to deliver it.

on 3-phase motors, you can alter the power to each coil so that you get a constant torque. total different animal.

you can get a treadmill motor that is really a DC permanent magnet motor that is run with an AC power supply. if you can find a treadmill, look for a small block near the motor, the motor would be connected to this. and usually, you can use a POT to change speed.

a stepper with 7 amps and 70 volts will deliver about 1/3 hp. and will get HOT enough to cook eggs. but, steppers over more power at low speeds and are not designed for high speeds.

Thank you Dave.

The application is to set up a vibration platform (which moves vertically (up and down) at 1 inch/sec). So I need a motor -> belt -> flywheel -> eccentric cam -> platform assembly rig. I will be doing vibration tests of packaged products on this platform (platform will steel and will be 200cmx200xcm). Our largest package weighs 78kg where the lightest will weigh 10kg ish. So there is a decent range of weights between 0 to 150 kg (including platform weight etc). Pretty much I am building a vibration simulator for transportation.

So I already had a motor that I could use but I am open to using a motor which would be best for this application and hopefully easy to setup and control with an arduino. Price doesn't matter as much as finding the right solution.

Best to work out what H.P. required and go from there.

Calculate on the maximum loads.

Think you will find the variable speed unit on a 3 phase motor the best approach, however that depends on a lot of variables like, escentric gearbox used, availability of 3 phase supply, finances etc. Trying to build these is more than likely beyond your ability though and not cost effective anyhow.

I have to agree. it sounds like you have an industrial application.

a 3-phase motor with a VSD will be a solid platform. the VSD will cost about half as much as the motor ! fractional 3-ph motors are not low cost.

I think a 1 hp VSD should be around $150 and a motor around $125 look on automation direct.

typically controlled with a PLC, but you can make an Arduino do that. alas, 'CLIC' plc is less than $150, has 1 Analog in, free software, and 2 4-20 outputs. you have to read the specs. if you contact a supplier, you should get them to make sure the parts are all compatible.

I cannot say I know anything about the application, other than your spec's are too soft for UPS. I think their trucks, or at least their drivers, go for over 50 G's with gravity drops of 10 feet to the pavement.

Thanks guys,

I'll definitely would like to try using an arduino to control this. Will calculate HP and look up the 3 phase motor. $150 and $125 are definitely reasonable pricing for this. Yeah this is an industrial application. I'll report back, thanks again Dave and Bluejets!

So I am going to need atleast a 1-2 HP motor and 1000+ RPM. Are there any motors out there that would be easy to hook up to an Arduino for speed control?

How would I control it with an Arduino?

With HV AC motors, not a simple task as you imagine.

Do some searches on AC motor variable frequency drives and you will see what I mean.

Example here ......