Month: October 2013

VFD Modification: Part 1

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First off I’ve been really tearing it up in my nerdery the last two weeks… It’s messy.. That happens so don’t mind the mess.

So I scored this sweet variable frequency drive (VFD) or also known as a VSD. It’s a Rockwell Automation drive that is to large for my application but it’ll work just fine. I figured I might have to tear out the entire front because I’m feeding it straight DC but they broke out DC to a terminal block ?! I’ll give it a try… I have a 96V power supply that was a long shot but it was no surprise two amps wasn’t enough just to power the electronics for configuration. It isn’t jumped to run… So this beast is a watt-hog just idling. I have a couple batteries I have to pick up in a few days; I am guessing I can start it up on a 48V/19AH string. The power down defaults to zero and I believe it’s set up to run on just enough to run the electronics. I guess I’ll see?! If this doesn’t run on DC (and maybe even if) I’ll gut the AC front end because it’s extra weight. Check out the terminal strip..DC is on the left. Also… In case you’re wondering its about 90lbs.. A lot of heat sink!

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Hardness building…

Hardness building the last few days.. I chose a combination of .093 and .062 MOLEX connectors because I have a ton of them… and Vetco Electronics has a ton of surplus ones (at .59/.79 ea).. if you want to dig and find matches to… (hint, only like 10% of what they have has a matching gender…) I also bought about 50$ in pins and extra connectors as I know I’ll be using a ton of these. I probably should have bought more of them from digikey but I wouldn’t have ended up with the assortment. The real ugly purchase was my desire to stick with oil/moisture resistance MTW wire. I think it’s also known as appliance wire? Anyways it’s flexible, has nice thick insulation. Disclaimer: I have endless supplies of controls wire with is a  low voltage 18 ga power limited wire. Usually plenum rated. … all that wire is usually free for me. This wire isn’t really acceptable.. I spent about $70 on wire and that was totally out of left field. I found a couple spools (~80ft) of it cheaper than new and Vetco has decent prices even compared to eBay so I did buy most of it from Vetco. There is a bunch more 22 ga if someone is looking for it, I wanted 18 ga.

The stepper driver is a CENTENT CN0142 I purchased off eBay for $40. It’s very easy to us. I don’t know if it’s not totally obvious but the “direction” and “pulse” signals are open collector. You’re supplying a ground to signal input and +5VDC to the input labeled so.  Overly obvious.. well maybe. Rock solid stepper driver so far. I accelerated my Sparkfun NMEA23 motor from 2kHz to 14kHz fairly quickly in five programmed steps to get my speed up. Worked like a charm… lets see if i can still pull that off under more load.

Also of interest?  I had to boot up an old Windows 3.11 laptop to use an old programming app for some super old controls. (Okay, not 1970’s stuff… but early 90s anyways).  It’s been a while since I’ve seen that screen (photo below). I didn’t have a mouse but it magically came back to me pretty quick!

harnesses, harnesses, hardnessed....

 

Making up harnesses with painfully expensive MTW wire.

Windows 3.11

Weekend stepper fun!

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I got got home to take delivery of this front end frame piece. Now I’ll be busy this weekend working on electronic steering. The PIC 16F1509 will be controlling all steering functions. I’ve written a remarkable amount of code for how long it’s been since I worked I a project with a F628A and 18F1330 motor control for the Roomba sumo bot. This project has gotten painfully expensive despite scoring some nice freebies. I spent way too much on wire because I want MTW or Teflon.

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