Variable speed help/ convert single speed BIII

[billf]

Hi all,

I'm looking for some of your expert advice! I have a 115v, 1.5 HP Bader III (Leeson motor) and would like to convert it to variable speed in the most economical, efficient way possible. I am not an electrician, but can handle the basics.

Mike Hull was kind enough to give me advice on another forum, and I'll happily take all the help I can get. Thanks in advance

Bill

[chrisinbeav]

Well, probably the cheapest way would be to get a set of pullies. If you want more versatility you'll need to step up to a controler of some kind.

Chris Nilluka

[Ray Rogers]

I agree with Chris, pulleys if you are staying with that motor. Otherwise, you'll need a motor and controller that was made for variable speed. There is a thread somewhere on VFD motors and controllers that looked very good to me, priced about $400. They also seem to do an excellent job of maintaining torque at low rpm's which is a problem in some variable speed systems. Or, Leeson makes the DC motor and controller which is usually in the $600 range.

There are others, like tread mill motors that you might consider if you were building from scratch but they wouldn't seem to be a good choice with a Bader although I guess they could be made to work with about the same effort as a pulley system.

The popular little router controls will come to your attention sooner or later but they can't handle your horsepower ........

[sleepy]

bill

if you want to do this yourself find a good electrician, electric motor service in your area make friends and ask questions or if you do some research you can probly do this yourself. there are usually plenty of books about motors and motor control at local library. almost any motor can speed can be controlled with frequency and voltage manipulation though depending on setup this can shorten the life of some motors. if you want to spend the time and learn this can be done for $100-200 maybe less. hope this helps

[fitzo]

Isn't a Bader3 a direct-drive like the Bader2? The drive wheel attaches to the motor shaft?? Changing my "2" over to pulleys would present quite a challenge, I think.

[billf]

yeah, the BIII is direct drive - motor shaft to drive pulley, so the pulley thing would be a pain - I'm leaning to the motor/controller idea. It looks like my hope of retaining my original motor to run it and using sep controller isn't optimal - it seems going to a 220 single phase and using a VFD is what folks seem to prefer ( Mike Hull gave me a good link)
Any idea what I can use the 1.5 hp Leeson for - don't want to scrap it. 3450 rpm is kind of fast for a horizontal disc, have a buffer already - Any other ideas?

[Jamey Saunders]

If it's not in bad shape, a lot of electric motor shops (where you'd get your VFD motor and controller) will take used motors in on trade. The one I used to work in would do this so they'd have a supply of cheap second-hand motors for folks who couldn't afford a new one, or a supply of emergency stop-gap replacements when one performing an important function (like a ventilation fan) grenaded and needed to be replaced.

It does you no real long-term good, but it's something to think about.

[tmiller5087]

you can't use a regular motor with a VFD? well one without a capacitor. I never knew that course i ain't no wire nut either.

[chrisinbeav]

Oh your going to like this... Bill look what I found today...

http://www.electrokits.com/electroni...ontrol/208.htm

A/C motor speed controller, DIY kit $40.00. From what I can tell it sounds like it would work!

Don't worry about the message I sent you earlier today. I ended up buying a motor elsewhere. I will be using this controller. If you want I can be the test dummy, but it might take a while before my grinder is completed.

Chris Nilluka

[mdagley]

Chris/Bill,

Nope, this DIY speed controller ain't gonna work. This type of controller is only for brush type motors. I don't believe the Leason Bill has is of this type.

Mike

[chrisinbeav]

Well shoot.... it was worth a try...

Why not try Leeson? It looks like they carry their own controllers. They would probably know which one will work best?! The only thing I can see is that they may be difficult to get.

Chris Nilluka

[Talis]

I was just checking the link on the DIY controller, and the main problem that I am seeing is the fact that it will only handle 5.5 amps!!!! I don't know about the BMIII, but my BMII draws nearly 30 amps at startup (or it did when it was 110, I have since rewired it to 220v, so I'm not sure what it pulls currently) but I would guess it still pulls 15-20 at startup, then drops down to around 10 or so...

[billf]

Thanks to everyone for their help - yeah, the motor does pull more than 20 amps at startup. Looks like I'm going the new motor/VFD route - checking out some sources. Once I get things going I'll check in with my findings

Bill

[chrisinbeav]

If you look around that website there are other controllers available. That one just seemed the most applicable. I read the review on it and the gentleman that used it, used it for a saw that is 3hp running at 5000 rpm. And he is having no problems... It was just a suggestion. I do not know any of the specifics of the motor that Bill is using. My last suggestion was to just use a Leeson controller or get advise from Leeson. If anyone is going to know anything about a Leeson motor, good chance it would be them!

Chris Nilluka

[fischerknives]

Somebody tell me why this won't work. It seems almost too simple, so it probably can't.

This thread got me thinking, which can be dangerous, about what goes into a dc motor speed controller. What do you need? In it's simplest form - A way to regulate voltage and a way to rectify voltage. Now I know there's filters and probably capacitors to clean up the voltage going in and out of the rectifier (diodes) and trim pots and so on.
But just for laughs, I connected my titanium anodizer to my belt grinder (dc motor) and it ran it fine through the whole range of the variac. I connected a voltmeter in parallel and monitored the voltage out of the anodizer. Nice and smooth and steady from 0-120 vdc.
I didn't do any actual grinding on it because I think the bridge diode is pretty low value. But you can get bridges that are rated for 20 or more amps for a few dollars and variacs rated for 10 -20 amps, pretty cheap. mill some fins in a chunk of aluminum and you've got a heatsink, maybe put in a filter and capacitor to smooth it out. I guess you could even stick a couple of pots in there to set min and max voltages (aka speed). This wouldn't be much harder than building an anodizer.

Why won't this work???

Looking for advice. Has anybody else tried this?

Thanks,

Fischer