Control speed of AC motor in a laminator

[mughoj]

Hi,

I'm trying to slow down the AC motor on a laminator for better laser toner pcb transfer.

The laminator is a Texet A4 Laminator and I thought, wrongfully, that I could use an http://www.ebay.com/itm/2000W-50-220V-25A-AC-Motor-Speed-Controller-Adjustable-Voltage-Regulator-PWM-/141354323945?pt=LH_DefaultDomain_0&hash=item20e95fcfe9 for that purpose. Unfortunately the motor seems to run at the exact same speed whether it receives 40V or 230V.

I haven't done much with AC, but I'm guessing that the frequency of the power is controlling the speed of the motor. How do I adjust the speed of such a motor? Is there a speed controller or a simple circuit to adjust the frequency of AC power?

I've attached a picture of the motor. The text on it also gives a clue to the speed being frequency controlled as I states 50/60hz and 5/6 rpm.

Mogens

[Zero999]

It's not just the frequency which needs to be changed, it's also the voltage.

As the frequency is reduced, the voltage needs to be reduced with it. To run at half the speed, the motor should be run at half the voltage and frequency.

[tautech]

I'm trying to slow down the AC motor on a laminator for better laser toner pcb transfer.

I never bothered, just do 2 passes.
Then you can still use the laminator for normal use.

[mughoj]

I never bothered, just do 2 passes.
Then you can still use the laminator for normal use.

I may just end up doing the same giving the circumstances, but even with the mod working I could still bump it up to full speed for normal use.

[wasyoungonce]

The motor, TY-50AF is a synchronous AC motor (50~60Hz) 220~240V AC.  It must be internally geared as the output is ~2.5/3 RPM.  There is a range of motors in this series but they all run a little faster RPM.  Your easiest bet is to replace the motor with something that runs lower RPM but this may be difficult to find.  Other than that you need to build a variable frequency drive for the motor. 

I multi-pass my PCBs thru my laminator no problems.  I also tape down the print to the PCB (leave the PCB oversize and cut it down later) with Kapton tape to stop it moving.

[mughoj]

As the frequency is reduced, the voltage needs to be reduced with it. To run at half the speed, the motor should be run at half the voltage and frequency.

Is this kind of AC motor rarely used? Or would the compatible motor controller just be too expensive for most people to bother? I can't seem to find anything that exactly fits the bill. Maybe I'll look at some reduction gears instead.

[mughoj]

Other than that you need to build a variable frequency drive for the motor. 

Yea, that's probably beyond my current skill level. At least I'm not keen on experimenting too much with high voltage, even though I do have a couple ideas how it could be done. Ideas like that are much better suited for 5v

I multi-pass my PCBs thru my laminator no problems.  I also tape down the print to the PCB (leave the PCB oversize and cut it down later) with Kapton tape to stop it moving.

I've done the same with pretty great results. I actually thought all the toner was transferred, but after a very close inspection, I could see some pixel sized specks that didn't get transferred. Nothing that would matter I think, but I haven't etched it yet, so I don't know. I'd just prefer only having to put it through once and have the results I want. Especially if it were as easy as just putting a $3 ebay item in the thing. Turns out it wasn't.

[Cliff Matthews]

It's not just the frequency which needs to be changed, it's also the voltage.

As the frequency is reduced, the voltage needs to be reduced with it. To run at half the speed, the motor should be run at half the voltage and frequency.

I'm thinking out loud here..  can this be do-able almost with junk box parts?
A triac can adjust voltage duty, while an alarm clock transformer+7805 can run a flip-flop dividing line frequency to send cancel pulses to the gate via opto-coupler for every other cycle?

[mughoj]

I didn't forget about this thread, but I decided to change the gears instead, so now it's running a 4.5:1 gearing compared to before. It's a fixed speed solution and not what I was going for, but at least that made me feel, that I didn't have to reassemble the laminator with the tail between my legs

Thanks for all the input.