motor control circuits

[MRMOTION]

Schematic
I have a couple of motors that I’d like to put in use one for my lathe the other as a blower for my tablesaw.
The motors are brush type motors with permanent magnets operating on a voltage 130V DC drawing proximately 14 amp and rated at 2 hp.
I’m looking for motor control circuits that I can build, I’m not looking for off-the-shelf product.
I’m looking for circuits that do not have transformers.
The motor for my tablesaw, which will create a vacuum system only needs to be turned on or off
So a circuit to takes 120 V AC and converted to 130 V DC would work well in this application.
For my lathe I would need a circuit that would take 120 V AC and convert it to 130 V DC
variable 0 - 130 DC.
I have built some PWM motor controls and light controls but only in the lower voltage range of 12 to 24 volts, so building a circuit of higher voltage higher amperage is not much different but a great challenge.

 

[ScottyUK]

For the supply voltage you're considering you could feed a thyristor-based full converter or semi-converter and likely get reasonable results, assuming you don't manage to kill yourself in the process. Designing a 2 HP DC drive isn't a trivial task. An open loop firing circuit controller would be fairly trivial, but making it into speed controller would take a bit more doing. Quite a bit in fact.

A word of warning: playing about developing circuits directly connected to the utility supply can get out of hand very easily. At least consider doing the development on a lower voltage, low energy supply before going for the high power stuff.


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If we learn from our mistakes I'm getting a great education!

 

[MikeHalloran]

Not long ago, a friend of mine had somebody convert his SB lathe to DC drive. The instructions that came with the PWM drive were confusing, so the guy miswired it a little. I was asked to fix that, and change to pushbutton reversing switches.

The thing that struck me as odd was that the motor was rated 130VDC, but there was no DC supply; the PWM just chopped the AC line.

With the wiring straightened out, it worked something marvelous, except for being easily stalled. The PWM unit had a tach input, but my penurious friend refused to spring for a tach, which would have made the drive rock-solid.

I think but cannot swear that the PWM drive was from Grainger, and cost less than 200 USD. Rolling your own will cost you more than that in parts.

Do buy a tach generator to go with it; you'll be glad you did.




Mike Halloran
Pembroke Pines, FL, USA

 

[panelman]

we've used number of these

http://www.kbelectronics.com/kbsearch/descriptions/popup_kbic_240d.htm

for what they cost it's not worth thinking bout DIY