# Controlling a 220 volt ac motor

Hi,

I am planning on controlling the speed of a 220 volt, 170 watt, 3.5 amp AC motor, that I salvaged from a washing machine so I assume that it is 3 phase, that will get the required readings from a flex sensor with regards to speed.
Now my question is how would this be done, I did some reading on the internet and read about people using TRIAC circuits to this but I unfortunately don’t fully understand this so if it is a plausible method with the flex sensors please inform me as what needs to be done and if not please still inform me as what needs to be done.

Thanks.

It totally depends what type of motor it is. If its an induction motor. then you cant control the speed with a triac. Induction motors rotate at a speed which is dependant on the supply frequency. If its a brush type or universal motor , then the triac will work.

Sorry if this is a stupid question but I have never worked with ac motors so how do I tell the difference between a universal motor and an induction motor?

Andaroid: Sorry if this is a stupid question but I have never worked with ac motors so how do I tell the difference between a universal motor and an induction motor?

Induction motors have a solid metal armature ("squirrel cage") without brushes or wires. Universal motors have field coils on the stator and a wound armature with brushes to supply the current. It is "universal" because it works on DC or AC - if the supply polarity reverses both the armature and field current reverses resulting in the motor continuing in the same direction.

Universal motors are easy to control, reversible, but noisy, induction are quiet, have one (efficient) speed and direction, and are used for fans and pumps mainly. You can control the speed on an induction motor by limiting the current, but they are inefficient in this mode (3-speed mains fans are like this).

Sounds like mine is a universal motor, so I have 1 more questions. Where is the best place to learn how to make a TRIAC circuit for speed control?

Sounds like mine is a universal motor

Perhaps, but washing machines do not typically require speed control. I vote for an induction motor. Can you post a picture of the motor.

Here you go. I tried taking pictures of the places that I thought were important.

You have an induction motor.

The only way to modify the speed of an induction motor is with a "variable frequency drive" ("VFD"). They are expensive devices; they modify the frequency of the AC current to change the motor speed.

I was really hoping that it wasn’t but thanks for the help

I am certain that the motor in your picture is not induction motor, it's a brushed AC motor (i.e. a universal motor calibrated for use on AC). The reason I think this is that the plate on that motor gives a fixed frequency, but gives two very different RPMs and the corresponding current. Here is the UK, in domestic washing machines at least, the motors are always brushed motors. This is necessary so that the motor can be speed-controlled to turn the drum at a slow speed for washing, and at one or more much higher speeds for spinning.

To verify that it is a brushed motor, at the end with the wiring, see if you can find 2 graphite brushes (probably replaceable) diametrically opposed to each other, pressing on a segmented commutator.

You can use phase angle control to vary the speed of a brushed AC motor.

I could not find any brushes so I did research on the type it had written on it (don't know why I didn't do that earlier) and found out that it is an induction motor

Thanks for the help

Hi, single phase induction motors usually have a start winding, old Hotpoint top loaders used these with a current activated solenoid and mechanical clutch. Three phase induction motors start and are usually controlled for direction of rotation by reversing any two leads. There must be thousands of machines with universal motors which would be more suited to your needs.Surely you could source one of those? John.

I know I was hoping this one was going to be a universal motor, I will be doing some hunting in for a universal one

Thanks

I was wrong, it is indeed a single phase induction motor. It has 2 sets of windings (2-pole and 16-pole), so it can do one spin speed and one wash speed, by switching which winding you use. I've not come across a motor like that before.

It is from a westpoint frontloader washing machine

you can find many tutorials on how to run the old type induction motors of washing machines, and the new type brushed motor with tachometer

dc42:
It has 2 sets of windings (2-pole and 16-pole), so it can do one spin speed and one wash speed, by switching which winding you use. I’ve not come across a motor like that before.

Your furnace blower would be the place to look unless you paid the extra bucks for a DC motor.