Electric Motor Help

[jakeco88]

I'm working on my first electronics project, and I need a motor which will rotate both directions. I salvaged a motor from an old ice cream maker which will do just that. However, it changes directions somewhat randomly. I need to control the direction. Below is a diagram of how it was wired in the ice cream machine. Any advise? If you need more information, let me know. Thanks in advance.

Jake

 

[duke37]

Some small AC motors will start in either direction.
DC motors will run in the direction set by the polarity.
AC/DC universal motors will run in the direction they are wired.

Your motor has solenoids to make the magnetic field so I assume it is an AC motor without a specific direction. To get it to start in one direction only, I would expect to see a capacitor in the supply.

How does is work at all with
1. A DC supply
2. The supply shorted.

 

[Harald Kapp]

Below is a diagram of how it was wired in the ice cream machine.

Impossible. "+" and "-" are shorted in your diagram.
Are you shure the motor runns off DC at all? I'd suspect that an ice cream maker's motor is operated directly off the AC mains.
The motor you show looks like this one, which means if you remove the red wire your drawing is basically o.k.
Still, this motor would run off AC, not DC.

Unfortunately the datasheet doen't tell much about the motor, especially not how to control the direction of rotation.

 

[duke37]

Harald
Thank you for the link to the motor details.

It appears that the motor is a sychronous motor which will run in either direction, I have a motor in my microwave which rotates the food in a random direction. I have a sychronous motor in an electric clock which is similar. The clock has to be switched off and on until it runs in the right direction. If only we could make time run backwards.

 

[jakeco88]

Impossible. "+" and "-" are shorted in your diagram.
Are you shure the motor runns off DC at all? I'd suspect that an ice cream maker's motor is operated directly off the AC mains.
The motor you show looks like this one, which means if you remove the red wire your drawing is basically o.k.
Still, this motor would run off AC, not DC.

Unfortunately the datasheet doen't tell much about the motor, especially not how to control the direction of rotation.

Thanks for the info, especially the link to the datasheet. I assure you the diagram is correct; I was likewise confused by the fact a + and - went to the same terminal. I've never tried running the motor off DC.

 

[jakeco88]

Harald
Thank you for the link to the motor details.

The clock has to be switched off and on until it runs in the right direction. If only we could make time run backwards.

This is precisely how this motor operates. If I switch it off and on, it will change directions. The direction it rotates appears to be completely random; is there any way to control this?

 

[duke37]

If it is not running on DC, then how can the power supply be labelled + and -?.
Some clocks with synchronous motors had a little lever which jams the motor if it starts in the wrong direction. It then bounces to give the correct direction.

What do you know about electricity? Do you know how to deal with it safely? Are you using an isolating transformer or an RCD?
I have the impression that you may be putting youself at risk.

 

[Harald Kapp]

I still think this is impossible. Regardless of AC or DC, you short the power supply.

What is your mains voltage? 115 V or 230 V?
It looks like this motor can be operated in two ways: both coils in series for 230 V operation, both coils in parallel for 115 V operation. If you have 115 V, you could try to phase shift the current through one coil by inserting a series capacitor into the wire that leads to one coil. This might force the motor to start in only one direction by skewing the magnetic field within the motor. This is a mere theory of mine, though.

 

[jakeco88]

If it is not running on DC, then how can the power supply be labelled + and -?.
Some clocks with synchronous motors had a little lever which jams the motor if it starts in the wrong direction. It then bounces to give the correct direction.

What do you know about electricity? Do you know how to deal with it safely? Are you using an isolating transformer or an RCD?
I have the impression that you may be putting youself at risk.

Pardon my use of the "+" "-". Here is a more accurate depiction. I still don't understand the red and black wire running to the same peg.

 

[Electric Al]

I would suggest , when switch is closed you will have a dead short !

 

[duke37]

I would think the input black wire should connect to the black loop. This puts the two coils in parallel for 120V as Harald says in #8.

 

[jakeco88]

I would think the input black wire should connect to the black loop. This puts the two coils in parallel for 120V as Harald says in #8.

I just tried this. The coils immediately began to overheat.

 

[jakeco88]

I would suggest , when switch is closed you will have a dead short !

I would think so too. However, it works fine when the switch closes.

 

[jakeco88]

I still think this is impossible. Regardless of AC or DC, you short the power supply.

What is your mains voltage? 115 V or 230 V?
It looks like this motor can be operated in two ways: both coils in series for 230 V operation, both coils in parallel for 115 V operation. If you have 115 V, you could try to phase shift the current through one coil by inserting a series capacitor into the wire that leads to one coil. This might force the motor to start in only one direction by skewing the magnetic field within the motor. This is a mere theory of mine, though.

Main voltage is 120. I just rewired the motor as show in the diagram and it works. I tried moving the black wire to the black loop as suggest by another, and the motor overheats.

 

[Harald Kapp]

Are you sure the red "wire" is a conductor at all? Measure its resistance.