Different specs for dimmer switch speed controls ?

[govtmule]

I'm starting my first winder and I have a newbie question.

I pulled a motor from an old sewing machine and wired up a dimmer switch bought from the local home improvement store for a speed control. The dimmer starts, stops, and controls the speed like I wanted it to but it doesn't really start from 0 rpm.

There seems to be a threshold where the dimmer is not supplying enough juice to make the motor turn and then once the dial is turned beyond that point, the motor "jumps" to a start, probably a little faster than I'd like my first few winds to be.

Do dimmer switches have different ratings and should I be using one rated higher or lower ?

Thanks in advance for your help and advice.

Steve

[guitician]

Since bulbs start with a low resistance, and then it rises as the current heats up the filament, you could try adding a small series resistance. Just a thought.

[Regis]

- Harbor Freight Tools - Router Speed Control

[David Schwab]

- Harbor Freight Tools - Router Speed Control

That's a better way to go for motor speed control than a dimmer. It's better for the motor too.

I have that same router speed control... I used it on a router.

[govtmule]

I stopped by harbor freight tonight and got the motor speed control. Hopefully I'll be able to test it out tomorrow. Thanks for the advice guys.

Hey David, if you don't use a dimmer or this motor speed control, what do you use ? Custom made circuit ?

Steve

[David Schwab]

Well I have a Schatten winder that had a speed control built in, of course. But that's broken, so now I power the winder with a variable speed hand drill. It was supposed to be temporary until I fixed the speed control, but it works so well I just left it that way.

I'm building a new CNC controlled winder, so I'm not in a rush to fix the Schatten.

If you use a sewing machine motor, why not use the speed pedal they come with? My very first winder was like that.

[govtmule]

If you use a sewing machine motor, why not use the speed pedal they come with? My very first winder was like that.

The speed pedal that came with the sewing machine was way too sensitive. It went from 0 rpm to max in a very short distance. I figured it would be too dificult to control and keep at a constant speed while winding.

[Neal]

- Harbor Freight Tools - Router Speed Control

Thread hijack.... would this be a safe way to control the speed of a Leslie motor? I've got a single-speed Leslie unit I scavenged out of an old organ, and I'd love to be able to control the speed without burning up the motor.

Sorry for the hijack!

[tonedeciple]

I stopped by harbor freight tonight and got the motor speed control. Hopefully I'll be able to test it out tomorrow. Thanks for the advice guys.

I use this same speed control on my sewing machine motor. When I switch from OFF to VARIABLE, the motor runs very slowly. As I turn up the knob the speed gradually increases all the way to max rpm. Overall, it's very controllable. Now I just need a reliable counter and I'm all set.

[RedHouse]

The speed pedal that came with the sewing machine was way too sensitive. It went from 0 rpm to max in a very short distance. I figured it would be too dificult to control and keep at a constant speed while winding.

Try using both.

On my 2nd winder I used a dimmer to controll the top speed (like an RPM limiter) then inserted the original sewing machine foot pedal into the motor circuit and use that for starting-up and spinning-down. With both in play the footpedal can turn my winder's bobbin flange at a crawl if I want it too, then when I have it pressed all the way down the dimmer controll the top speed, it works well.

I suppose a lot of it depends on how much pulley offset you have on yours. Mine was like a 3" bobbin flange pulley size driven by a 3/4" drive pulley on the motor, it think my particular motor was a 5000 RPM sewing machine motor like this one:

Thread hijack.... would this be a safe way to control the speed of a Leslie motor? I've got a single-speed Leslie unit I scavenged out of an old organ, and I'd love to be able to control the speed without burning up the motor.

Sorry for the hijack!

IIRC, the Leslie motors are the old "brushless" type like in old record players and such, I'm not certain but I don't think you can use this type of speed controller with brushless motors.

[Magnut]

Instead of a dimmer, use a ceiling fan speed control. (looks just like a dimmer) It is made for a motor load and will work better than a dimmer. In fact some dimmers won't work with a motor. It should work as a leslie speed control too. If it's a brushless motor then it's an induction motor just like a fan motor.

[Joe Gwinn]

Instead of a dimmer, use a ceiling fan speed control. (looks just like a dimmer) It is made for a motor load and will work better than a dimmer. In fact some dimmers won't work with a motor. It should work as a leslie speed control too. If it's a brushless motor then it's an induction motor just like a fan motor.

Be careful. Ceiling fan speed controls are a switch and a handful of capacitors that are inserted in series. The motor must be induction for this to work, while sewing-machine motors are universal wound.

Brushless DC motors contain an electronic controller plus a form of induction motor, so a ceiling fan controller probably won't work at all, and may damage something.

There are lamp dimmers that work well with universal-wound motors. Lutron is a good brand.

Feeding the motor through a fullwave rectifier bridge greatly helps at low speeds. Put the bridge between the dimmer and the motor with the AC side towards the dimmer.

[RedHouse]

...Feeding the motor through a fullwave rectifier bridge greatly helps at low speeds. Put the bridge between the dimmer and the motor with the AC side towards the dimmer.

Can you do a quick sketch of that Joe?

[Magnut]

I didn't have any issues using the fan speed control with the sewing machine motor. I have since moved away from that type of setup however. Is the Leslie motor DC?

I think using a rectifier is probably a very good idea with a universal motor. I may have to pull that out of the closet and hook one up.

[Joe Gwinn]

Is the Leslie motor DC?

I don't know this motor, but if it has brushes, it's DC (well, AC/DC most likely). The motor nameplate should say. Do you have photos?

[Joe Gwinn]

Can you do a quick sketch of that Joe?

Sure. here:

[walcen]

I'm not sure if this is helpful to anyone at all but after much experimentation I've found that these 450 watt light dimmer's work really well on vertically every AC motor I've tried and it provides great speed control although the brush-less motors tent to hum a little at low speed.

kind regards to all

Walt

[RedHouse]

I'm not sure if this is helpful to anyone at all but after much experimentation I've found that these 450 watt light dimmer's work really well on vertically every AC motor I've tried and it provides great speed control although the brush-less motors tent to hum a little at low speed.

kind regards to all

Walt

Aw darn! most of my motors are horizontal...

[RedHouse]

Sure. here:

I think I get the drift Joe, thanks.

How does that help low speed?, and what effect does DC have on an AC motor at low speeds?

Also your PDF maker seemed to cut off some of your verbiage, this is how it displays on my screen (Acrobat-9):

[David Schwab]

Brushless DC motors contain an electronic controller plus a form of induction motor, so a ceiling fan controller probably won't work at all, and may damage something.

There are lamp dimmers that work well with universal-wound motors. Lutron is a good brand.

Joe, would a lamp dimmer work with a brushless DC motor? I'd like to fix my Schatten winder so I can sell it. I could try replacing the rectifier on the speed control board, but it seems like it is a faulty design since they seem to be failing on people.

[Joe Gwinn]

I think I get the drift Joe, thanks.

How does that help low speed?, ...

I don't recall exactly why it works, but I did read this in a textbook on motors, and my experiments did show that DC worked better. I think that it will have to do with the self-inductance of the motor windings.

and what effect does DC have on an AC motor at low speeds?

Well, an "AC/DC" motor is not an "AC motor", it's a universal-wound DC motor with laminated iron so it won't overheat when fed with AC. That's what is meant by "universal".

A universal wound DC motor has field winding and rotor winding in series, so the direction of rotation does not change if the polarity of the supply is reversed. To reverse, one must rewire the motor.

Also your PDF maker seemed to cut off some of your verbiage, this is how it displays on my screen (Acrobat-9):

Try downloading again from the original post. I replaced the file.

[Joe Gwinn]

Joe, would a lamp dimmer work with a brushless DC motor? I'd like to fix my Schatten winder so I can sell it. I could try replacing the rectifier on the speed control board, but it seems like it is a faulty design since they seem to be failing on people.

Is it really a brushless DC motor? They are expensive. Small DC motors can have brushes inside that are not externally visible.

But to answer your question, I would be surprised if a brushless DC motor was happy being driven by any kind of lamp dimmer.

Standard 110 volt lamp dimmers put out far too much voltage for such a motor. One can get lamp dimmers intended to drive low-voltage (12 volts being common) halogen lamps through a transformer. Such a dimmer with transformer and rectifier bridge could work, but this is getting expensive.

I would replace the blown rectifier with an electrically larger component first.

Actually, Schatten may offer repair and/or parts, given that it appears to be a design problem.

[-Elepro-]

Joe, would a lamp dimmer work with a brushless DC motor? I'd like to fix my Schatten winder so I can sell it. I could try replacing the rectifier on the speed control board, but it seems like it is a faulty design since they seem to be failing on people.

no, dc brushless is a three phase motor and needs its driver....
but... try to change rectifier with a bigger one....
post a photo of the control board....

[David Schwab]

Is it really a brushless DC motor? They are expensive. Small DC motors can have brushes inside that are not externally visible.

It's a small DC motor. I guess it probably has brushes. It has a small controller board on one end. It certainly wasn't expensive.

Work with dimmers?

[Joe Gwinn]

It's a small DC motor. I guess it probably has brushes. It has a small controller board on one end. It certainly wasn't expensive.

Work with dimmers?

Depends on the controller board.

Actually, doesn't the Schatten run off a wall wart? If so, the voltage will be low, and direct connection to a 110 volt dimmer will cause sparks and fire.

I've never seen the Schatten, so I'd like to second Elpro's request for photos.

[walcen]

Aw darn! most of my motors are horizontal...

You see? this is what Virtually happens when your eye sight begins to Virtually fail you and spell check Virtually gets it wrong. Sorry for the typo.

Back on subject, for DC motors between 12 and 35 Volts I have found that a simple pulse width modulator works really well and provides good motor speed control. they are easy to build from a kit or purchase from E_Bay.

Here are a couple I made, the cheep one is good for 12-15 volts DC.
The other is good for 12-35 volts DC

DC Motor Controller Kit (K3070) | Dick Smith Online Store

Bi-Directional DC Motor Speed Controller Kit

I hope this is helpful.

regards

Walt

[David Schwab]

Actually, doesn't the Schatten run off a wall wart? If so, the voltage will be low, and direct connection to a 110 volt dimmer will cause sparks and fire.

Oh yeah... duh...

I've never seen the Schatten, so I'd like to second Elpro's request for photos.

Here's some I took a while back. When I get a chance I'll take the non working speed controller board out and take a photo of it. I had replaced the motor, which turned out to be fine.

[David King]

The LM 317 is an adjustable voltage regulator. You can get from 1.5 to 35V at up to 1A. So it doesn't look like a PWM based speed control but a variable voltage controller. I can't really imagine why he did it that way. Looking at his PCB it doesn't seem like electronics is his forté.
There should be a good sized filtering cap(s) somewhere in there which I'm not seeing..

The + and - stamped into the back of the motor case tells me that's a DC motor, probably 12V.
How many volts is the wall wart putting out?

Mabuchi only makes DC motors, they are the worlds #1 producer according to wikipedia.

I looked through their online catalogue and couldn't find one that looked like this.
If you know the dia and the voltage, you can look it up here:
http://www.mabuchi-motor.co.jp/en_US...ct/p_0303.html

[-Elepro-]

.... this is a simple pwm controller

DPRG: A Simple PWM Circuit Based on the 555 Timer

[David Schwab]

The LM 317 is an adjustable voltage regulator. You can get from 1.5 to 35V at up to 1A. So it doesn't look like a PWM based speed control but a variable voltage controller. I can't really imagine why he did it that way. Looking at his PCB it doesn't seem like electronics is his forté.

That probably explains why the thing failed.

There should be a good sized filtering cap(s) somewhere in there which I'm not seeing..

I think there is. I'll have to open the thing up and take a photo. I broke the switch on the pot it used, so I replaced the pot with a new one and a seperate toggle switch. So now the board is hanging from the pot.

The + and - stamped into the back of the motor case tells me that's a DC motor, probably 12V.
How many volts is the wall wart putting out?

9V, 500mA.

Mabuchi only makes DC motors, they are the worlds #1 producer according to wikipedia.

I looked through their online catalogue and couldn't find one that looked like this.
If you know the dia and the voltage, you can look it up here:
Search by Required Motor Performance | MABUCHI MOTOR

I had the part number for the motor. It's on the parts list in the instruction manual. I couldn't find that motor listed anywhere. When I got a new motor from Schatten it wasn't very expensive... maybe $12. I don't remember.

[Joe Gwinn]

That probably explains why the thing failed.

LM317 is a very widely used regulator chip. The problem is that the circuit isn't designed to handle the load imposed by the motor in practical use:

If one stalls the motor by preventing bobbin rotation, the current will shoot up. This is perfectly normal, and must be accommodated.

DC motors can generate large voltage spikes, which spikes can blow unprotected solid state devices. Are there any protective components in parallel with the motor? (A capacitor helps, but isn't usually enough.)

I think there is [a big filter capacitor]. I'll have to open the thing up and take a photo.

Motors don't really need their DC to be clean, so there may well not be such a capacitor.

[wallwart is] 9V, 500mA.

Probably a 6-volt motor. Motors are not that fussy.

[RedHouse]

Oh yeah... duh...



Here's some I took a while back. When I get a chance I'll take the non working speed controller board out and take a photo of it. I had replaced the motor, which turned out to be fine.

I like how they hold the motor in there with a can-cap bracket. Reminds me of Danelectro thinking.



Seems like they could/should have gone to the trouble of making a proper PCB instead of that strip-board circuit ...for the kind of money they get for those winders.

[Steve Conner]

That's a motor from an old cassette deck, with a built-in speed regulator. I remember them from dismantling old stereos as a kid.

The actual motor is in a rubber mount inside the can, and the little round regulator PCB is soldered to the back of it. Maybe that's what has blown and you can bypass it.

[tonedeciple]

That's a motor from an old cassette deck, with a built-in speed regulator. I remember them from dismantling old stereos as a kid.

The actual motor is in a rubber mount inside the can, and the little round regulator PCB is soldered to the back of it. Maybe that's what has blown and you can bypass it.

You could use an rpm selector from a turntable and name the pickups "The 33-1/3rd," "The 45" and "The 78"

[rdrr]

There are lamp dimmers that work well with universal-wound motors. Lutron is a good brand.

When you say lamp dimmer are you talking about those floor lamp dimmers that you plug the lamp into or are you talking about something along the lines of a florescent safe light dimmer? If it's the floor variety then it's just a matter of wiring a sewing machine motor up to a plug and plugging that into the dimmer, right?