g320 servo drive initial testing - problems and questions

[fbmstar]

Hello all,
I am in the process of initially testing my new Gecko 320 servo drive, and am not getting very far. Sorry for the long post, just want to make sure whomever will be able to help has most of the info they need.

Firstly, one question. Does the power supply need to be regulated? i'm just using a transformer and rectifier for my supply and am getting over the +5V max for the motors. I'm measuring 31V on the geckos main and motor power lines for the 24V motor(24V transformer) and 98V for the 75V motor (74.5V transformer). The stepper drive manual had a large section on recommend power supplies, and since the servo manual didn't, I'm assuming it isn't terribly important?

I have not been able to perform the encoder test with any results. I'm using a fluke 73III DMM, but don't know where the test point is. I found a post talking about this, and have tried every imaginable test point to no avail. I never see any voltage decrease or increase no matter how slow or fast i spin the shaft. any help in explaining this would be greatly appreciated

I initially hooked up a Sanyo denkie 75 volt, 3.4 amp motor with a 1000 ppr encoder resolution. I got the motor to operate somewhat. It would stay still and "sing" under power. It would also jog both directions, but would not go past ~1000 rpms(random guess). it would just lock up after getting to a certain speed in both directions.

This being my first attempt at servo-ing, i decided to buy some new motors off of ebay for testing. They are small 24 Volt, 3 amp motors, have 500ppr encoders with 40mA draw. Both are brand new and were packaged very well. I still can't get the encoder test to work.

link to motors if needed:
http://cgi.ebay.com/ws/eBayISAPI.dll...2380&rd=1&rd=1

I've reached the point where they just spin when I power up the drive. Actually, the spin in one direction for ~½ second, the reverse and go up to full speed. They just keep going after that. Both motors behave the same.
I have tried switching the encoder wires and motor power wires multiple times. I have checked my wiring over about 12 times. The step and direction signals are borrowed from my already working z axis on my stepper driven mill. I am getting:
4.8 volts at the +5V common.
5.5 on terminals 5 and 7.
31V on the motor supply wires.

The motor will stop (abruptly)when i input a Jog command. While holding the key however, they start to speed up again, then stop, then speed up, etc. the process repeats itself.

attached are a couple of pics of drive and motor hooked up if it helps.

thanks in advance for you help.

Brian

[fbmstar]

I've answered some of my questions over the past weekend, and come up with a few more.

firstly, the test point is the "ring" that is perpendicular to the jumper. ground is the (-) of the blue capacitor lead. (see blurry pic below)

for the small motors, i had the encoder hooked up wrong.
black: ground
white: +5V
red: channel A
green: channel B
i had the red and white switched.

apparently, it does not fry the encoder if hooked up backwards. any thoughts on this?

also, i got the larger motor with 1000ppr encoder operating pretty well, but read on here that 1000ppr is too much for the gecko? maybe it was a higher resolution. can anyone tell me what range of encoders i could use without any expected problems?

I'm still wondering about the power supply however, does this need to be regulated before entering the gecko?? the motors are working for now, but i don't want to ruin them later on because of overvoltage.

The motors are all working pretty well, but i can't seem to get them up to full speed. None of them have a load, and i adjusted the frequency in turbocnc up to 40000 hz, which should be more than enough i figure. The larger motor with 1000ppr encoder probably gets up to 1000 rpms or so. it works fine, just won't go faster. the smaller motors (500ppr) get up to about 1/2 their full speed when i applied 24v directly to them. is this a software/computer problem, encoder problem, or driver problem? I don't even know where to start looking.

lastly, can anyone elaborate on when to use the jumper setting on the drive. i only have one drive, and don't remember it coming with a jumper. if it did, then i lost it. how small of a motor should it be for the low inertia setting, and when would one want to use the anti-dither setting?

more to come later,

Brian

[mlaws1172]

A few things you might want to consider.
1.the power supply doesnt need to be regulated but you do need to install some capacitors. Figure about 2000uf per amp
2. When you do install the cap.s the DC voltage will increase times 1.41
3. I believe the max. voltage is 80VDC
mike