Paul & Sabrina's cheap DIY 144v motor controller

[MazdaMatt]

Paul, why not have PCBCart do the power sections as well as the control section? Milling those things must suck. If you do mill them, it would probably be worth the time investment to get that mill CNC-adapted. Keep me in mind when you start pricing that out, as i can probably beat the price of any 3-axis stepper control board and the one that we make is loaded with protection circuitry.

[nubie]

Originally Posted by edown

Just for those looking, there are 2 "killer" forklift motors on Ebay right now..

DC Motor #8504667 36/48v For Forklifts & Electric cars - eBay (item 360155468078 end time May-22-09 12:24:18 PDT)

DC Motor #2774337 36/48v. for forklifts & Electric Cars - eBay (item 360155467252 end time May-22-09 12:19:58 PDT)

Originally Posted by ev59rag

Local pick-up only...

It looks like you can call or email them and arrange for it to ship 'motor freight'

225 lbs so it will have to shipp motor freight

We have many others in stock

call for more info. or shipping cost.

Way to go Paul, I hope you get the PCB's in record time

[GrahamMc]

Originally Posted by ev59rag

Local pick-up only...

That is only about 3 hours from me. Might have to bid it.

[MPaulHolmes]

Originally Posted by MazdaMatt

Paul, why not have PCBCart do the power sections as well as the control section? Milling those things must suck. If you do mill them, it would probably be worth the time investment to get that mill CNC-adapted. Keep me in mind when you start pricing that out, as i can probably beat the price of any 3-axis stepper control board and the one that we make is loaded with protection circuitry.

I would LOVE to get a 3 axis conversion. I think that one guy... (hahaha!) Adam is going to help with the group buy. I don't want to wear him out, though! Maybe I'll get a 3 axis one in the fall, when I get my hot little mittens on $500-$600. I'll definitely email you when I want to do that. China charges $40-45 for group purchases for milling the power section (does that include an UNHOLY amount of drilling holes of various sizes, up to 5/16" diameter? That wouldn't be too bad to pay in that case!) Right? Darn my nested comments.

If I had a CNC, I could do it way cheaper than $40! I can even add vias! I'm doing that in this one. ya! Just turn that little bugger on, go upstairs, eat some cereal, come back, switch out the bit, hit "enter", go eat another bowl of cereal (raisin bran), etc... Something would probably catch on fire, but that would be awesome.

[lectruck]

Originally Posted by edown

Just for those looking, there are 2 "killer" forklift motors on Ebay right now..

DC Motor #8504667 36/48v For Forklifts & Electric cars - eBay (item 360155468078 end time May-22-09 12:24:18 PDT)

DC Motor #2774337 36/48v. for forklifts & Electric Cars - eBay (item 360155467252 end time May-22-09 12:19:58 PDT)

Local pickup only or freight charges $116.09 to Maryland or North Florida

Don

[brihoo2k]

Here is a 4 axis cnc control board I bought at a very good price new version 4 Axis Stepper Motor TA8435H driver board - eBay (item 110377733782 end time Jun-14-09 19:20:00 PDT) they're only 58 dollars plus another 20 dollars for shipping. If you have some printers laying around you could scavange up some stepper motors may not be able to run your current mill with steppers out of a printer but could run a dremle on some drawer slides or window slides. Then you could use google sketchup and mark 3 for the free software.

[adamj12b]

Ok, CNC retrofits is one of my specialty. I would recommend using a Gecko Drive 540. They are one of the most advanced stepper motor drives available for the hobbyists. The 540 has 4 motor drives capable of 3.5A each in one fancy enclosure aluminum enclosure.

Here you will find a package deal of the 540, 3 motors, and a power supply. It is the second one down. The motors were designed specially for the 540's motor drivers, and are wound so the inductance match's the drives optimal needs.

2 of the best features of the drive are Mid-band resonance compensation and Auto standby current (70% current). The drives actually morph the output to maintain torque while rpm increases. The second best part is the auto current reduction which lowers holding current to lower motor heating.

As for software Mach3 is defiantly the best way to go. The free version is able to run 250 lines of code. For $175 you get a license file emailed to you customized with your name. The license moves the line limit up to 10 million lines. You are able to use this license on any number of machines if there non profit. If you are using it for profit, you need a license for each machine.

Your machine would be simple to convert as well. Just create some simple mounts that mount on the existing bearing mounts on the machine, remove the hand wheels and attach some love-joy connectors to the screws and the steppers and finish mounting the steppers.

The 540 is one of the easiest to setup. Just 1 parallel port cable is the connection between the motor controller and the computer. The motors attach with DB9 connectors that are provided with the 540. In the DB9 connector the 4 motor wires attach as well as a current limiting resistor to tell the drive how much current to limit the motor to.

I use some of the 251 Gecko drives which are the same as the drives in the 540, but without the 540 case and breakout board. These drives increased the rapid speed of my machine about 2 times. They are one of the best investments I have made for my machine.

As for motor sizing for your mill. I would not try and use a stepper motor smaller then 200 oz-in. It would not have the power to move the table well. The 387 oz-in motors in that package are more suited to that size of table.

Well I think that covers most of it. If I missed something just ask.

-Adam

[MazdaMatt]

Okay, lets steer this rig back into the "motor controller" lane.

A while back someone made the suggestion of not jimmy-hacking the box and using a standard electrician's panel instead. I wouldn't go with a home depot box designed for house service, but I totally agree that a standard service panel is the way to go. I was thinking that it would be nice just to have something that is off-the-shelf and made for electronics to go in... but then i realized it would be EXTREMELY beneficial to have the connetions made inside a box instead of outside. The safety (ahem, liability) factor is a big deal when people are hooking up 144VDC. I think a couple people aorund here have already been shocked by their DIY EV's... was it fun? In a box it would be protected from weather, errant screw-drivers, stupid people's prodding fingers, lost babies... you could install a fan on the side and have convection cooling. The boxes come with the sides covered in punch-outs, too and there are standard gromets for them as well.

I'll see if i can find a link to a supplier...

[adamj12b]

You mean something like these? This is a Hoffman ASE12X10X4. The dimensions are just as like in the model, 12 x 10 x 4 inches. They are about 40 bucks. Might be a little pricy, but they are very tough box's. With a thin rubber strip for something, the lid could be made water tight when screwed down. They have knock out's for 4, 3/4 electrical connectors in the ends, perfect for the 2 battery cables and 2 motor cables. They also make a 12 x 10 x 6 if more headroom is needed.

-Adam

[MazdaMatt]

http://www.exmweb.com/2_products/ind...enclosures.php

http://www.exmweb.com/pdfcat/5412esspch.pdf

What do you think? Use a hole saw to make ports on the bottom for your wires to go in, use grommets to protect them from the edges. Professional looking and more importantly, SAFE.