Paul & Sabrina's cheap DIY 144v motor controller

[blackpanther-st]

Originally Posted by MPaulHolmes

Actually, it's 2-3 days by hand including drilling holes. I need lots of breaks so I don't get sloppy.

DCB: The economy of motion issues come from the fact of making it easier to do it that way by hand. Also, the paths should be changed a bit. I chose them so that everything was a multiple of a half crank on the mill. That's not quite optimal.

Also, my mill has some slop, so I try to only go from up to down, and left to right to avoid any gear slop. (It's sort of hard to explain)

JayC: Ebay for 3 ounce copper.

Yes gear slop does suck! I was using an old and a bit sloppy lathe at work to make my custom DE plate for my motor and at certain points on some cuts, the cross cut feed would shift over 20 thousands as the force vectors changed on the bit.

It was cool watching the automated mill; the things I could do with something like that.

Paul a while back I mentioned heating those bus bars up on a gas stove, but if you are concerned about over heating them, I am thinking that an electric hot plate would be more controllable; by electric hot plate I am referring to the cooking kind, as apposed to a warmer, and preferably one of the ones with a flat metal surface for the burner. (probably an antique item at this point) but something like that would due.

Some of them only have a few heat settings, but a high power light dimmer would give you a very precise control over the temperature.

[dcb]

Originally Posted by MPaulHolmes

My dog died with a sausage in her mouth from breakfast:

Condolences, she looks like a sweetheart. I lost my dog recently too, it &(@#$ sucks hard.

[Intrigued]

Originally Posted by MPaulHolmes;111658
My dog died with a sausage in her mouth from breakfast: :(
Note: She's not dead in this picture. That's how she used to sleep. Her name was doggie. I put her on here by accident, because she's the same color as a bus bar, so I got confused.
[IMG

http://i419.photobucket.com/albums/pp280/MPaulHolmes/Pumpkin.jpg[/IMG]

Awww... bummer. My sister lost her Boxer some time back. Name was Bob. She had the big lug cremated, and he has his own spot up on the shelf.


Someone name their controller the doggie memorial controller, please!

[chapper]

Hello Paul
Many and profuse thanks for this thread; it has taken over as my morning first read.
I've been concentrating on modular power sections, separate from a digitally generated sine wave control section, for a 3-phase, brushless, AC motor. I've found some things that may help you, at least with the hardware end.
1. Instead of tin plating, consider silver plating. Here's the system I'm considering, "Cool-Amp" for plating the buss bars and PCB, and "Conducto-Lube" for an electrical/thermal interface. No heating, soldering, delaminating, alignment or parts placement errors. Not as cheap as tin plate and solder, but if parts can be replaced, reused or reclaimed with no more than a couple of hand tools, it looks good to me.
[I just did a quick ballpark (using dimensions from the rear of my mind) for the cost to silver your controller, PCB, buss bars and spreader: ~$3.75 to plate, ~$2.10 to thermal compound; not outrageous.] Check the spec sheets on each for coverage and prices.
Cool-Amp Conducto-Lube Co.
2. When it comes to cutting, drilling, etc. any kind of metal, I prefer "TapMagic" cutting fluid. Try a machine tool supply shop. "TapMagic Aluminum" is also good for cutting/drilling some plastics.
Tap Magic Metal Cutting Fluids
Also, in a photo I noticed the point of the drill you're using. It doesn't look like one I would choose for copper (or aluminum) and here's why. Do a search for this link instead of clicking on it here. In Firefox, it's the first entry on the first page.
Choose The Best Drill Point Geometry: MMSOnline.com
3. If the copper thickness on the PCB is a major concern; consider electroplating copper onto whatever raw PCB stock you can get your hands on, up to any thickness you want. You already have a copper substrate, just rough it up, scrub it clean (grease free), dip in copper sulfate and apply a low voltage. We did this in junior high decades ago. .010" or even .100" would be easy. You could even make multi-level (not layer) copper PCB. You'll need cross-section area calculations for the current to be carried by a particular trace.
This is fun.
John

[MPaulHolmes]

John! Those are some awesome ideas! I'm going to look at that stuff! Thank you! It is fun, isn't it?

I just finished Ben's bus bar drilling and smoothing. The PCBs should be here tomorrow, so in the interest of time, I'm just going to tin plate and conductive silver epoxy this batch since I already have the stuff, and I want to get those things out like yesterday! Then I'll probably order the fancier stuff for the next controller(s). You can't beat silver!

I made the 2.75" bolts into flat head screws with a dremel, since it cuts down on the machining of the aluminum baseplate, and they evidently don't sell 2.75" machine screws! jerks! That way you don't need room for a socket wrench. Sorry Adrian! I didn't think if it at the time! Oh crap! I need to take care of finishing the drilling for the aluminum base plate for both ben's and Joe's. Ben's is different since the Ebay guy sent the wrong length on accident (not enough for 3 baseplates), so I'm using a previous heatsink, with a different width for Ben's. Oh man. details details!

[bennelson]

Originally Posted by MPaulHolmes

Ben's is different...

Yeah, like ANYTHING is standard on the Electro-Metro.

I got really good response to the Electro-Metro while I was showing it off at the MREA energy fair last weekend.

Many people were impressed with the economy of building it.

Just imagine the response once we get it up to freeway speed again with the rebuilt Cougar controller!

I think next year I may have to race the Meyers NMG.

[watt-a-mezz]

Sorry to hear about the loss of your dog, it does leave an empty space in a home. We have two, and I know it would be tough if anything happened to either one of them. Was putting the cables in my nissan truck today, and I was wondering if all goes well with your 144v controller, would there be smaller versions? Cougars are big, wombats are small(96v?).Just a thought. Take care,Watt

[MPaulHolmes]

Hey Ben! Well, it turns out that Ben's is too different. I didn't think I could make it work well. It already had holes in the wrong spots, and it was the wrong dimensions. Hondo finished the enclosures and shipped them today, so I ordered another 0.375"x7.8"x37" aluminum plate from Ebay, thanks to those donations! I also picked up the 5/16" brass bolts and nuts. I wimped out on the copper heat spreader (went with aluminum). Should I buy 16 of the larger 820uF capacitors? I don't know. I have 16 of the 470uF caps that might be OK. Kelly uses thirteen 330uF caps in their 144v controller (hehe, let's be like Kelly). I don't have the $54.72 + shipping to get the 820uF ones.

I have $13.01 in the paypal from donations right now. Should Ben's really be an experiment in frugality? Or should I wait until I get enough for it? Or if anyone wants to pay the balance, I could send them the $13.01 and they could order the caps from Digikey and have them shipped here. I just don't want Ben's to blow up! He's showing that car off all over the place!

Watt: You can give it any voltage you want, from 0v up to 144v, with no modifications. The only way the controller will be physically smaller is if the current rating is lower (fewer mosfets then).

[Royal]

Hello Paul:

Do you have drawings of your metal parts. I could make them for you with AutoCad. I am not expert at Autocad but I could do ok on simple parts like yours.


Thank you,

Royal

[watt-a-mezz]

Sounds good,Paul. I thought you had said something before about that, but I wasn't sure it was the same one. I tried to use the donate button on Ben's link, hope it worked. I hope you can use it. The Nissan has about maxed out my cards for parts, but I am almost done with it, So then I will send more. Take care,Watt