Paul & Sabrina's cheap DIY 144v motor controller

[NiHaoMike]

Originally Posted by williamson

I'm going to TRY to post the 8 pages. There are rweally 3 inductors on one page-OK for me but to make it more clear, there are 4 inductors to make L1, and one has an extra few turns, then L2 is on the same page. 7 out of 8 pages are over the size limit. What do I do?

Put the PDF on a P2P network of some sort and post the link.

[bigh]

you can sign up for some free hosting: Free cPanel Hosting. If you don't want to sign up you can send me the plans and i'll host them on my free megabyet site .

[bigh]

Hi Paul,
Great work on all of this. You're making me very excited about the open3phase and higher power version of this controller.

I'm reading through the installation instructions dreaming about making the controller. I've noticed a few totally minor issues (hope you don't mind). They're pretty mild issues though- i'll warn you. :P

Page 14 - it'd be better to use heat shrink. I find that after a while (esp in hot environments) the tape will unwind.

Page 17 - the little clips are fit over the cable inside the shell, so that if you pull the cable and its attached it won't break the connections. It ads strength to the cable.


Take Care,
Haydon

[MPaulHolmes]

The Sync. Rec. control boards have been shipped! They should be here in a couple days. I made the gcode for the surface mount current sensors that I plan on using at 1000 amps. Just finished soldering those nasty little buggers. Now, I just need to mount to the bus bar, after calibrating it. ya! In bulk, they are like $2 each. Can wait to see how they work!

I also finished the control board for the charger today. phew!

[CamLight]

I've been watching this thread for a while now...great work!!!
I think I can finally contribute a little bit.

Over many years, I have gained a LOT of experience in dealing with MOSFET cooling with the custom electronic loads I design. With the higher power unit being discussed, and ways to add additional cooling, I had a few thoughts...

- As mentioned earlier, MOSFETs can only be cooled from their "rear" mounting plate. The front gets hot but you'll never move any meaningful amounts of heat through the epoxy case.

- Water-cooling can be quite effective at moving the heat from point-sources to another location, but that comes at a cost, literally and figuratively. It's much more expensive than other methods, is MUCH more prone to failure (especially when shock and vibration are involved), and requires lots of maintenance. And once you move the heat away with a water-cooling block, you still have to deal with the heat. This requires a much larger and more expensive setup than using an effective combination of MOSFET, MOSFET mounting, heat spreader (if needed), heat sink, and fan...all are important. My latest electronic load sheds over 400W (continuous) of heat from four MOSFETs and the heat sink and fan are only the size of your fist.

- I highly recommend using Type III (hardcoat) anodizing for the MOSFET mounting surface, whether it's the heat sink or just the spreader. It will insulate up to several hundred volts, is tough as nails, and has an incredibly low thermal resistance due to it being so thin. Typically 0.5mils penetrates the aluminum and another 0.5mils sits on the surface. This will allow you to mount the MOSFETs without the heat sink being electrically hot. Lots of benefits there.

- Doing a quick thermal analysis of the existing setup can give you a lot of info regarding what might have to be done when raising the power levels. It can also show how much headroom there might be in an existing design, or how close it's running to the MOSFET's thermal limits. I'd be happy to help with this.

Looking forward to seeing how the project evolves!

[MPaulHolmes]

wow! What is this type 3 anodizing?! How do I do it? Can I send in a block of aluminum to someone, and they anozide it?

[dave koller]

yep as I said here http://ecomodder.com/forum/162424-post3007.html
Easier to send it out for anodizing BUT fun to do your aluminum in colors !

CamLight - tell him how he can even do it himself! It is not hard and I am sure you can come up with the power supplies...

[williamson]

Where is this "C-P" near my name that I should click on to open "pictures and albums" I don't know what I'm doing! kindest regards to all.

[apowers]

Originally Posted by williamson

Where is this "C-P" near my name that I should click on to open "pictures and albums" I don't know what I'm doing! kindest regards to all.

It is at the top of every page where it says welcome on the right side.
after you click on that on the left side of the next page under networking.

[CamLight]

Originally Posted by MPaulHolmes

wow! What is this type 3 anodizing?! How do I do it? Can I send in a block of aluminum to someone, and they anozide it?

Unfortunately, as I understand it, it can't be done DIY very well. It takes a lot of current and requires a very carefully controlled temperature bath. Otherwise, it's pretty well the same process used for the colorful anodizing often seem. It's just a lot tougher. Half the hardcoat anodizing actually sinks into the pores formed by the acid bath (typically 1/2mil deep) and half sits on the surface (typically 1/2mil thick). What's on the surface forms the "insulation" and is incredibly tough. Do not plan to do any machining or drilling of a hardcoat anodized piece of alumunum! It will eat up your bits.

But, a large number of anodizing facilities can do Type III hardcoat anodizing (the military uses it a lot). The only problem is that it comes in only one color, dark gray/black. They typically charge a lot fee for a basket full of parts. The more parts you send in at a time, the less expensive it will be for each part.

If you don't have a lot of parts (100+), it can get expensive. But, if you're pushing the thermal envelope for a design and can't have a "hot" heat sink or use mica or thermal pads between the MOSFETs and heat sink (because of their high thermal resistance), hardcoat anodizing is the way to go.