Motor Over Temp

[Hermes Sandoval]

I got a Gravograph LS600, have been working with it sporadically over the last 10 years.

I'm getting "ERROR; MOTOR OVER TEMP" message on the LS600 LCD screen when I turn the system on, and then it halts.

According to the information from Sanyo Denki, both the 103H7123-1743 and the 103H7126-1745 stepper motors work with 24v DC but I get 48v from the leads in the X axis of the LS600. I attach a mapping of the readings on the 4 leads of each motor's connector, on the electronics rack.
275868
I still haven't found the malfunctioning part.

Any suggestions will help.

Thank you

[Amos De Pasquale]

I would need a circuit before making any concrete suggestions, but here are some ,
1. with the back of your hand, can you get to the motors and feel if one is actually getting hot!!
2. If you do have a circuit, read the actual output from the power supply.
That is all I can suggest without seeing a circuit, I hope someone with more intimate knowledge of your machine can shed more light, Amos

[Richard Rumancik]

Do you get the message from a cold start? If so then I would suggest the temperature sensor (I assume there is one somewhere on the motor) is giving a false reading. Perhaps even a broken wire running to it. Try to determine what device is monitoring the motor temp.

The rated motor voltage and the applied voltage from the motor driver circuit could be quite different. It is not uncommon to drive steppers with much higher voltages than might be on a nameplate. So I don't think you can necessarily conclude anything from your measurement.

[Hermes Sandoval]

Thank you so much for your input!

I'm sorry I didn't clarify from the beggining;

It was engraving well for the past 7 months, 1 month ago the machine showed an error msg; "ERROR END OF TRAVEL". It turned out a connector for a limit switch was signaling continuity on both leads, meaning it was giving a closed signal, when it shouldn't unless the limit switch was activated. Long story short, my tech guy was able to find the burnt microchip and replace it.

Then, Few days ago, while in the middle of an engraving the X axis stopped moving, but the Y axis and the laser tube kept working, when I stopped the machine the LCD showed this new error "ERROR MOTOR OVERTEMP" and from then on it will always show me that error when starting the machine.
Worth mentioning; the Y and Z motor start up and can't be moved by hand when I turn the machine on, the X axis motor just stays off, I can move it freely. The motors won't overheat, at least for a few minutes.

The error persists if I disconnect all the motors or some of em. I tried with a different motor, new motor, new wiring; to no avail.

I've swapped the eprom, the driver microchip, a few other chips from X axis conector to Y axis conector, I've extracted some mosfets and reinstalled them, the problem persists at all configurations. The X axis motor does not start.

Any help would be appreciated.

[Hermes Sandoval]

Well, placed my order with marko @ Lightobject.con for a new DSP to adapt it to my Gravograph, hopefully we'll be back on business in a few weeks. Will still keep trying to get the electronics rack repaired, though.

[brandon paradise]

Did you ever get your over temp error fixed?If so what was the issue? Im having the same problem on my LS600.

[Hermes Sandoval]

I'm sorry it took me too long to respond, Brandon, in the end I had to swap all the electronics for new ones, bought em @ lightobject.com, The LS600 has been working fine for a couple of months. I keep the original electronics rack, maybe just out of nostalgia, since I have no plans on get in it repaired. Refurbishing the whole electronics section was the best option, since the electronics rack is not modular, it's a big block of crammed electronics, if 1 chip goes wrong, you cant just replace the defective part at a low cost.

If there's anything else I can do for you, don't hesitate to drop me a line.

Hermes Sandoval
hermessandoval@hotmail.com