MLCS Motor Speed Control

[staffwalker]

This is not a complaint about the product but a request for info. I'll find a use for the product sooner or later.

I ordered MLCS #9410 Solid State Motor Speed Control which is built to operate routers. It was only 34.95 so thought it was worth that amount in the hopes it would work on other tools, Taig, buffers, the old washing machine motor I use to run one of my buffers. So far it won't work on any of those tools I have tried it on. The motors just shutter, quake but don't run. Instructions say it works on any (Universal-AC/DC-brush type motors).

The same instructions say it will not work on (AC capicator start induction motors). I therefore assume all the motors I have tried it on so far must be of that type.

My question, how do I know which type motor each is if that information isn't on the name plate?

[bscofield]

This is not a complaint about the product but a request for info. I'll find a use for the product sooner or later.

I ordered MLCS #9410 Solid State Motor Speed Control which is built to operate routers. It was only 34.95 so thought it was worth that amount in the hopes it would work on other tools, Taig, buffers, the old washing machine motor I use to run one of my buffers. So far it won't work on any of those tools I have tried it on. The motors just shutter, quake but don't run. Instructions say it works on any (Universal-AC/DC-brush type motors).

The same instructions say it will not work on (AC capicator start induction motors). I therefore assume all the motors I have tried it on so far must be of that type.

My question, how do I know which type motor each is if that information isn't on the name plate?

I've investigated these for the same reason- but from what I can tell they only work on brush face motors, as you've discovered. I've also found that brush face motors are usually only found in hand tools.

This is the reason you find most people have rigged gears to get the desired speed. As for me, I'm going to disassemble a treadmill to get a variable speed motor. There are many to be had on craigslist- some for free

[ToddJohnson]

What you need is a motor speed control from AC Tech, probably an SF430. It's basically a small computer. The sort of speed control you got is for things like routers, etc. The AC tech model will run you about $300, but you can control a variety of motors with it and run them at full torque between 0 and 2X their usual max RPM's. Installation will require an HVAC electrician who is familiar with these. Make sure the model you get is matched to the phase type of your motors (single or three phase).

Good luck,

Todd

[wdteipen]

You could also just pick up a Variable Frequency Drive to do the same thing. You can usually tell if an AC motor has a capacitor because the capacitor housing sticks out of the side of the motor. If you have a lathe you can see what I'm talking about.

[staffwalker]

This was what I had always assumed and several of my larger motors do have the cap housing so I knew they were capacitor motors but others don't, such as the Taig lathe and a couple of drill presses. These have housings so I don't know what is inside. I suppose there must be a capacitor somewhere within. What really puzzles me is the washing machine motor, it doesn't have a housing and I can't see a cap anywhere, felt sure it would work but no. The gadget does work on several hand tools such as drills, etc., and it makes a hell of a dimmer switch. I'll find a use for it somewhere.

Thanks for all the comments, I don't know all I should know about motors. was just hoping there was a simple way to figure out capacitor, none capacitor motors by looking at them.

bob

[KurtHuhn]

The grand majority of AC motors will be induction motors. The exceptions are very high speed motors like in routers, and smaller motors like in Dremels, Foredoms, drills, circular saws, sawzalls, etc. They do this because it's incredibly easy to make a variable speed system with a brush-type motor and a simple potentiometer (usually in the trigger switch) to limit current. Unlike single-phase induction motors, single phase brush motors can easily have their speed varied just by limiting or increasing current to the brushes.

[ToddJohnson]

You could also just pick up a Variable Frequency Drive to do the same thing. You can usually tell if an AC motor has a capacitor because the capacitor housing sticks out of the side of the motor. If you have a lathe you can see what I'm talking about.

This is what AC Tech makes.

[KurtHuhn]

Will those work with single phase motors though? I always thought that VFDs were able to work off of single phase 240V input, but only output 3-phase on the drive side.

[ToddJohnson]

Will those work with single phase motors though? I always thought that VFDs were able to work off of single phase 240V input, but only output 3-phase on the drive side.

Kurt,

Did you not notice the part about "installation will require a trained HVAC electrician?" Basically, I'm not sure. I can do basic electrical work and just about anything with 12-volt, but when you start talking about enough power to pick you up and throw you across the room, I call someone and give them money to take that risk for me.

Todd

[KurtHuhn]

I can do basic electrical work and just about anything with 12-volt, but when you start talking about enough power to pick you up and throw you across the room, I call someone and give them money to take that risk for me.

That's no fun. I don't call it a complete wiring job until I've jolted myself enough to make me do the Tim Allen walk at least once.

[Frank]

Will those work with single phase motors though? I always thought that VFDs were able to work off of single phase 240V input, but only output 3-phase on the drive side.

Some devices will convert single phase to 3-phase output, otherwise you require a 3-phase output, installed by a "sparky", in your workshop. Either way, you need a 3-phase motor or a DC motor to get efficient electronic variable speed control.

Playing with HV is risky. I almost electrocuted myself trying to fault trace a plugged in toaster (standard line voltage in SA is 220v). If my sphincter hadn't snapped shut from the electrical impulse, I would probably have had soiled underwear. I was doing the Tim Allen walk for 10 minutes afterwards - the toaster went flying into the garbage can, after I managed to recover a steady pulse. What's more embarrasing, I was an electrical engineering student at the time.

[staffwalker]

Thanks for the info, I had a similar thread started over on the Taig Lathe forum, getting about the same musings there. Sooner or later I will figure out this motor thing and sooner or later when I am sure I must have it I will suck it up and lay out the 200-300 bucks to buy a real controller.

In the meantime I have found a use for my $34.95 speed controller. It works great as a hand control with my Foredom tool. Since their hand controllers run from $65 to $80 I'm ahead in the money outlay game. This thing works great, will run the foredom smoothly from low speed barely turning to it's full top range. I could never run at this slow speed with the supplied foot switch. Always hated those foot switches anyway.
bob gilbert

[KurtHuhn]

Will those work with single phase motors though? I always thought that VFDs were able to work off of single phase 240V input, but only output 3-phase on the drive side.

Some devices will convert single phase to 3-phase output, otherwise you require a 3-phase output, installed by a "sparky", in your workshop. Either way, you need a 3-phase motor or a DC motor to get efficient electronic variable speed control.

Ah, that's what I thought. I was pretty sure that single phase motors were fixed RPM motors unless you gave up a significant amount of torque at lower speeds. Like the variable speed grinders at the big box hardware stores - at the low end of the speed range you can actually stop the grinder by pushing a piece of pine into it.

Luckily though, solid state 3-phase convertors and VFDs seem to be fairly inexpensive these days, and 3-phase motors are dirt cheap since Joe Sixpack doesn't know what to do with them. Your entire workshop could be outfitted with those for just a little more than buying brand new single-phase motors and step pulleys.

[staffwalker]

Frank wrote: <you require a 3-phase output, installed by a "sparky", in your workshop.>

That's not always possible is it? I was told 3-phase requires an extra wire on the electric poles to carry three phase. Cities and electrical companies tend to only string that extra wire to cities' industrial districts and not through residential neighborhoods.

bob

[KurtHuhn]

As far as I know, that's true. What comes out of the transformers is single phase 120V and 240V supply (int the US).

However, you can have a rotary phase converter installed so that you can get 3-phase power to your entire workshop. It takes 240V single phase input and converts it for distribution to all your machines. There's a cabinetmaker not far from here that had one put in. It's verrah naaahz!

[staffwalker]

I think so, kurt, if you go out and look at your electrical pole, if you have two wires you are stuck with 110V but if there are three wires you can have 220V. If there are four wires you have 3-phase.

As an aside, I spent most of the day putting the Foredom final finishing touch to four pipes and I now understand why the normal Foredom kit comes with a foot switch rather than a hand dialed switch. I used the MLCS controller today and I have discovered when an accident happens it is a lot easier to take your foot off of a foot switch rather than reach over to turn off a hand switch. I have a rather chewed up thumb but what the heck, the controller stills works great. I just need to wear heavy gloves on both hands rather than only on the one hand.

bob gilbert