# Reversing the direction of rotation in a single-phase motor + diagram

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• #1
Tranquilizer
Level 2
Hello.
I make a circular saw for cutting metal (the so-called "rubber band"). I have a motor and the direction of rotation does not suit me. How do I change these spins?
I have already looked at the forum and found a few topics, but they did not give me a clear answer on how to do it.
So I am attaching a diagram of connections made by me under the cover of the engine's "lid". I am asking for a detailed explanation as I am not an electrician ;)

Diagram:

Regards.
• #2
forestx
R.I.P. Meritorious for the elektroda.pl
Cross the capacitor from point B to point A.
• #3
Zbyszek_64
Level 24
In order to be able to change the speed of your motor, 4 wires must come out of the motor. S2 and S3 are the work winding, S1 is the beginning of the auxiliary winding - the end is permanently connected to S2 in the motor. Regards.
• #4
marbac
Level 15
forestx wrote:
Cross the capacitor from point B to point A.

It's useless. Both ends of the start winding will then be connected to the same potential and no current will flow through the capacitor and the series connected winding. The magnetic field in the motor will pulsate instead of spinning and there will be no starting torque.
Just manipulating the motor terminal box will not change the direction of rotation. You need to disconnect the connection of the main and starting windings inside the motor, swap the ends of the starting windings and reconnect everything.
• #5
forestx
R.I.P. Meritorious for the elektroda.pl
I could add the fact that you can try and it will either start or it will not do anything.
Well, I have a motor at home - I do not know what is probably a washing machine (certainly not a fleece) and three wires are coming out of it. Measurements with an ohmmeter indicate something like a star, but asymmetrical (I do not exclude a short circuit, but it does not heat up). Swapping the capacitor connection in this way reverses its rotation.
• #6
Tranquilizer
Level 2
Thanks for the answers.
I'll try to take the engine down tomorrow. It is probably best if I lead out the other end of the auxiliary cable and then change the cable connections in the box itself.
If I have any problems or doubts, I will contact you again;]
Regards.
• #7
Tranquilizer
Level 2
Engine made . It turns the other way now.
I did as you suggested. I led the fourth wire into the can. It was actually connected inside the engine to the wire marked as s2 in my drawing (as Zbyszek_64 said). Swapped the ends of the auxiliary winding wires. I connected c2 to A, and this "pulled-out" wire to B. Now I can change the speed as I want
Thanks and regards.
• #8
Kepler
Level 9
In Wikipedia I found something like this: "In the case of a single-phase motor, the direction of rotation of the motor is changed by switching the starting capacitor from one winding to the other. Then the main winding turns into the auxiliary (start) winding, and the previously operating winding becomes the auxiliary winding major, resulting in a change in the direction of rotation of the engine. " It looks like the RPM can be changed this way, but the windings should be the same. In this case, it is theoretically possible to change the direction of rotation with three wires taken out of the windings. Correct me if I'm wrong.
• #9
masonry
Level 30
Wiki is lying. Most often, the starting winding is wound with a thinner wire and is not designed for continuous operation.
If you do as you described, the motor will only be fit for rewinding after a few minutes.
• #10
Kepler
Level 9
That's why I wrote that it would have to be a motor with the same windings, but usually they don't do that.
• #11
jacur
Level 32
Kepler wrote:
it would have to be a motor with the same windings, but they don't usually do.

A solution found in single-phase fans, less often in motors (230VAC gate actuators)
• #12
Michał Mikołajczak
Level 10
Hello

I have a strange situation and decided to write here.
I have a Chinese-made cylindrical grinder.
I bought a used one and after a few uses the engine crashed.
He had lost all power, he was spinning as if he were accelerating to certain revolutions.

I gave it for repair, they replaced the capacitor and the engine works.
But in the meantime, it changed its turnover. Ie. the drum turns in the opposite direction and this makes it impossible to work. I called the service and they laughed at me.

4 wires come out of the motor housing to the electrical box, two are connected with a capacitor and the other two are connected directly to 230V. Ie. phase through a fuse.

There is no question of any bridge or anything, because there are 2 wires, phase and zero.

My question: is it possible that the engine got stupid and changed direction or something ???? The situation is inexplicable, but the engine turns in the wrong direction.

Please help

Michael
• #13
Anonymous
Anonymous
• #14
sp3ots
Level 38
Hello !
Michał Mikołajczak wrote:
Hello

I had it repaired, they replaced the capacitor and the engine works.
But in the meantime, it changed its turnover. Ie. the drum turns in the opposite direction and this makes it impossible to work. I called the service and they laughed at me.

4 wires come out of the motor housing to the electrical box, two are connected with a capacitor and the other two are connected directly to 230V. Ie. phase through a fuse.

There is no question of any bridge or anything, because there are 2 wires, phase and zero.

My question: is it possible that the engine got stupid and changed direction or something ???? The situation is inexplicable, but the engine turns in the wrong direction.

Michael

The only thing they could do in the "service", apart from replacing the capacitor, was to assemble the motor the other way round (if they unscrewed it?), The drive axle may be inserted backwards in the stator, if it is at all possible.
Check if the engine was disassembled, show the photos.

Regards. Stefan

And the previous speaker, please do not stick to the same pattern wherever you find yourself:
https://www.elektroda.pl/rtvforum/viewtopic.php?p=13778052&highlight=#13778052

When four wires come out of the motor, it does not always mean that they are separate beginnings and ends of the windings, as in this case.
The constructor connected the windings in such a way that the fitter at the production stage could quickly and cheaply plug the capacitor and the cable from the switch (power supply).
• #15
Anonymous
Anonymous
• #16
sp3ots
Level 38
Four wires are physically led out:
• #17
Anonymous
Anonymous
• #18
sp3ots
Level 38
You can not read ?
In order to reduce the time of the operation of connecting the power supply and the capacitor to a minimum in the factory, which lowers the production costs.

Added after 6 [minutes]:

szelton wrote:
Michał Mikołajczak wrote:
4 wires come out of the motor housing to the electrical box, two are connected with a capacitor and the other two are connected directly to 230V

How are the wires in the box connected, some cube, soldering plus "heat shrinks".
If 4 wires come out of the motor, it is always possible to change the direction of rotation.
sp3ots wrote:
When four wires come out of the motor, it does not always mean that they are separate beginnings and ends of the windings, as in this case.
The constructor connected the windings in such a way that the fitter at the production stage could quickly and cheaply plug the capacitor and the cable from the switch (power supply).

It would only bring out 3 wires

Where do you get these crap patterns from?
The schematic is not correct, wrong.
• #19
Anonymous
Anonymous
• #20
krzysiek7
Moderator of Electricity
szelton wrote:
sp3ots wrote:
The schematic is not correct, wrong.

And so specifically?

More specifically, in these diagrams from post 15, one side of the capacitor is connected incorrectly.
• #21
Michał Mikołajczak
Level 10
Hello,

thank you for the hints, but knocks which did nothing.
The rotor cannot be turned because it is not symmetrical.

I paste photos, plates, cubes, capacitor and cables in the engine.

Cube:
the blue and red wires are 230V power supply, a capacitor is connected to the two black wires.

Stator:
the four blue, red and black wires are originally connected to the windings.

Remember the engine spins the wrong way.
• #22
sp3ots
Level 38
Take a picture of the motor so you can see how the wires come out of the winding.
An ohmmeter in your hand and take measurements to find out what wire colors are for which winding.
• #23
krzysiek7
Moderator of Electricity
Michał Mikołajczak wrote:
the blue and red wires are 230V power supply, a capacitor is connected to the two black wires.

This motor cannot change the direction of rotation. is connected properly.
• #24
Michał Mikołajczak
Level 10
It is impossible to change the rotation, but it spins the other way.
Tomorrow I will measure these circuits with an ohmmeter, today I have no option.
• #25
sp3ots
Level 38
Take a picture of the motor so you can see how the wires come out of the winding.
Other than what you posted.
• #26
krzysiek7
Moderator of Electricity
Michał Mikołajczak wrote:
It is impossible to change the rotation, but it spins the other way.

Michał Mikołajczak wrote:
The rotor cannot be turned because it is not symmetrical.

In that case, I do not see any other possibility of changing the direction of rotation, other than by turning the stator in the motor.
Stefan, two motor winding leads (working and auxiliary) are connected to the red wire and it is this connection that sets the direction.
• #27
sp3ots
Level 38
Krzysiek, my eyes didn't see it, that's why I wanted to make sure.
Every electrician should handle this by separating the bridged wires going to the red wire.
• #28
Michał Mikołajczak
Level 10
Now I thought that in fact, I wanted to turn the rotor and it was impossible, different sizes of bearings, but the housing with the stator may be possible. I'm going to check.

Added after 40 [minutes]:

I turned the casing with the stator 180 degrees, the screws matched, I twisted and it turns the right way.
the only thing that puzzles me is that now I have an electric box with the power input from the machine side and it seems to me that when I unscrewed the engine for the first time, the power supply was on the other side. But I think so, and my turnover is right now and I leave it that way. Thank you very much for help.
• #29
Arturo_77
Level 2
Hello.
-I have a question for everyone, is it possible to change the speed in a given fan motor without rummaging under the housing?

Added after 1 [hours] 57 [minutes]:

I just found a closed topic: UL-259B Silma Motor - How to change the direction of rotation? in it there is a photo of the same motor as mine, but it has a diagram of the windings and their connections:
-And considering the logic of whether or not you can connect as below, it would make sense as long as the windings are the same! (would they want to make different windings for them in the times of the Polish People's Republic?)