Diy Spindle Motor Controler

[miljnor]

I have a 130vdc treadmill motor that I am going to make a controler for.

I was thinking H-bridge mosfet driver with following criteria: Fwrd,revers and braking. with feadback control to controler (mach2 is my current choice) and the motor I am using is a 2.5Hp continious duty 130vdc 18.5amp.

That being said, I know there are probably drivers out there for this app. but I would like to DIY for learning experience.

So for the only controlers on the market I have found in a doable price range are non feedback or have on board style feed back that is SOOO slow to react as to not be usfull, or have a price tag that is in the stratosphere.

There are serveral H bridge schematics on the net but so far the only ones that I have seen are for low power robotics, nothing on the scale I need.

Since I am relatively new to electronics design, any suggestions would be helpfull. And who knows if we all put enough suggestions in we could probably put a good set of plans up for everyone to use.

My main weakness in design is not knowing the proper chips for this there are so damn many mosfets and mosfet controler chips out there it will take eons to sort through them.

thanks
Michael T.

[H500]

This is a pretty ambitious project due to the high voltage and current requirements. The mosfets that can handle this power level won't come cheap and you can easily fry 20-30 them to perfect the circuit. This is not something that can be expected to work the first time around.

Are you sure the motor is actually 2.5hp continuous? That's more current than what the typical 120v outlets can provide.

Why not start smaller, like 5 amps or so. A suitable mosfet might be the irf460. Did you come across possible bridge gate driver chips? I suspect that line powered ones are not that common.

[Fred in NC]

I might be putting my foot in my mouth, but the treadmill motors run fine from a ready-made Minarik controller, which can be bought surplus for $59 from Surplus Center.

[miljnor]

Are you sure the motor is actually 2.5hp continuous? That's more current than what the typical 120v outlets can provide.

well I could be mistaken on the 2.5hp continuous but the label on the motor say 2.5hp 3500 rpm 130vdc continuous duty PM motor PN # PWM3644-5127-2 .

As far as wall 120 wall current supplying enough amperage you might be right, because the motor is rated at 18.5amps and to my knowledge most house breakers are 10-20amps personaly I am willing to use 230vac as my source.

As far as perfecting the circuit goes, since there are alot of mosfet H-bridge schematics on the net, I don't see myself frying more than a couple of them. But hey maybe I am being unrealistic.

I might be putting my foot in my mouth, but the treadmill motors run fine from a ready-made Minarik controller, which can be bought surplus for $59 from Surplus Center.

You are quite right fred, the controler will run my motor but since the controler is a 12amp?? controler (which I am alread playing with) I wouldn't think it would take running this motor for long.

I have the controller that goes with this motor so worst case scenario is, I copy it. This controller is fed from 120v outlet, but, then the controler blows up quite a bit (which is why I have it). Maybe that is the way to go to save on cost.

This controller is very simple as things go and It probably wouldn't take me long to draw it up. First I will price all of the part out to see if its feasable.

Michael

[Fred in NC]

Michael, treadmill motors are designed for treadmills, and you plug treadmills in the wall outlet, usually 115 VAC at 15 AMP. I think the trick is in the PWM controller, it never gets to draw full amperage.

I am running a 1.5 HP 90 VDC in my wood lathe, with feedback for constant torque. It barely draws 2-3 amps! I can run the lathe, compressor and lights all in the same 15 amp circuit no problem.

[miljnor]

I am running a 1.5 HP 90 VDC in my wood lathe, with feedback for constant torque. It barely draws 2-3 amps! I can run the lathe, compressor and lights all in the same 15 amp circuit no problem.

quote from fred in NC

So basically you think that the minark 12amp controler would work fine with the motor I am using?

I have that controler and it works fine with the motor but I was worried about max amp draw.

I don't think wood lathes realy load motors up all that much or are you using it cnc style? Last I used a would lathe was in high school and with hand held stuff! Don't know that a tool I was willing to hold would realy load a motor up....or am I wrong, its been about 15-20yrs since then

Michael T.

[Fred in NC]

Michael, there is a heat sink that goes with the Minarik controller, to be used when running at full capacity. A few pieces of aluminum angle should make a good heat sink( LLLLL), or even heat sinks from computers, the kind that have a lot of spikes coming out.

[miljnor]

I take that as a yes, but with a heat sink? (got lots of those)

I will probably still go forward with a controller but base it of the one I have (thats Blown) for the motor I am using. There couldn't be more than 20-30 parts all told on the board and I've already priced about half of them <15.00us so far. All though the bourns 5k Trim pot has go (listed out for 14.00us, what is it solid gold?)

michael t.

[H500]

Maybe I misunderstood what you're looking for. Are you just looking for a speed control or a full PID type positional controller?

An h-bridge is much harder to do than a simple pwm speed controller. I believe those surplus controllers are relatively simple thyristor circuits.

Do you have a link to a high voltage h-bridge designs on the web? I haven't come across any that can handle the power level you specified.

[JRoque]

Hey Michael, the Minarik can easily handle that motor. I just cut a bunch of aluminum and had to stop for 5 mins while the motor cooled down. The controller, on the other hand, wasn't even near warm. I could not detect any temperature at all when I touched the heatsink. BTW, the Minarik I use is rated for 10A continuously; the 12A I mentioned before was peak as read with my setup. I honestly would worry more with a high output controller with a lower amperage motor than the other way around. Also, that treadmill motor is 2.5HP peak and can only be run at that rate with an external fan.

Again, if you need to get up and running the Minarik deal can't be beat. But, I know you want to brew your own so let's hear you design ideas for it. What do you want to accomplish? How much power are you looking for? What kind of motor feedback, if any? Have a circuit started already that we can see?

JR

[miljnor]

Sorry H500, Your well above my knowledge base when you start throwin them big words about! Thyristor???

As I stated in my original post the only H-bridge Designs I saw were for the low power robotics. Which is why I am posting.. to either find out that it is doable (without an engineering degree) or to find another cheaper easier way to do it. I am not set on an H-bridge design maybe a "simple thyristor circuit" is the way to build one. I was hoping all/some of the more experienced electronic people would give me a little direction.

Jroque
My design goals are: 1. Computer control
2. w/feedback
3. enough current/voltage for 2.5hp (that I aleady have, which is far in a way larger than the one you mentioned using)
4. A valuable learning tool

I will end up making a controler but the final design might be something other that my original connception..

I am inproccess now of diagraming the controller that runs this motor (the blown one). Also I may not have stated it but this motor/controller setup is from a commercial treadmill and not a Home unit. The two surpluss controlers are for home units, and home units are generally lighter duty.

[H500]

A thyristor is a power control device, like a mosfet or transistor, but with it's own quirks. You probably have a few in your house ...a lamp dimmer switch is a thyristor circuit.

I don't think a high voltage, high current h-bridge is doable unless you have considerable knowledge in power electronics. Most engineers would even find it challenging.

A more practical project might be to beef up your existing controller and add feedback to it.