Dear Mike and Gerald.

Mike first of all let me thank you for going the extra yard to explaining to me the intricacies involved with the power supplies.

Gerald I do thank you as well. I feel all my five motors are dead and gone. I read some articles on the net which proved to me that once a coil is damaged in a stepper they are not repairable. The magnetic power in the permenent magnets get's disturbed no sooner you dismantle the motor which I have done. They are are not reversible unless you have very sophisticated equipment.

Gerald,
Yes, Inductance is the important measurement. And, just as you pointed out, winding matching coils by counting turns and using wire from the same spool is about the only way that most of us would have to insure matching inductance between coils. Measuring resistance is an easy way to see if something has gone terribly wrong; but, because of all the other factors involved around inductance, measuring resistance is not the best way to verify that two coils will match when they are powered up.

Daya,
I'm really sorry to hear that the motors were destroyed. I hope that you can find the cause of the problem before you install the new motors.

Daya, it is indeed tragic to hear that your motors are gone. I asked at the geckodrive forum if anyone has hints on what might have caused it. Mariss has already replied: http://finance.groups.yahoo.com/grou.../message/13830 and he suggests a check that you must do on your drives to see if they are really okay.

Thanks Gerald I will follow your link and do the needfull.

For the others keenly following this thread and wondering if their motors might also get damaged in this way, I think I need to put minds at rest, but at the same time give the "heads up" on the danger of mains electricity.

Daya has agreed (in an offline note) that his ground system could not have been connected during his unfortunate incident. It cannot be stressed too many times that a solid ground system be connected at all times. I have maybe erred in always talking of grounding in the sense of avoiding interference, and seldom in the sense of safety. To me it was always so "obvious" that one grounds all metal parts so that fault currents flow straight to ground instead of via humans or other expensive components like motors or drives, etc. (Same as for lightning conductors - blowing 5 motors simultaneously was cause by the equivalent of a "lightning bolt"). If Daya's ground system was connected, the motors would not have had to carry the fault current.

What caused the fault current? Daya is still looking for that. It could have been a wire at one of his 230V limit switches that came loose or chafed through, or a faulty portable tool or extension lead was used at the table, or a welder touched the table by mistake, etc. etc. If a solid ground was in place, the damage would have been limited to a tripped circuit breaker or a blown fuse.

A GFI (or RCD) device would have given earlier warning of a disconnected ground system - still a highly recommended safety device.

Gerald After reading a number of your treads I think I will do as you suggested I will start with the control box. I have no idea what size stepper motor to start with ? I plan to cut MDF/plywood and sign material . I would like five stepper motors 2 on x, 1 on y, 1 on z and 1 on indexer. What do you suggest is a good place to start. Also what is two phase I am formulary with single an three phase, but not two phase Thank you glenn