Fuse Blowing! Please Help

[audioandy1762]

Hi All

I have just about finished my power supply and I am wanting to prove it before I go any further.

My system is using the Gecko 210, I have wired everything up as per the instructions checked and double checked.

Stepper motors are Nema 34 rated at 2.5volt @ 4.6 amp per phase, 8 wire, connected Bi-Polar parallel. The colour coding is as follows:-

Red * Winding 1
Red/White

Yellow Winding 2
Yellow/White*

Orange* Winding 3
Orange/White

Black Winding 4
Black/White*


The above is connected
Red and Yellow/White Phase A Gecko
Yellow and Red/White Phase B Gecko

Black and Orange/White Phase C Gecko
Orange and Black/White Phase D Gecko

The * denotes start of each coil, all of the stepper info was given to me by the motor supplier.

I have limited the Gecko’s to 2amp with a 18k resistor just for the trial, when I power up the supply, the 5 amp fuse which is protecting the Gecko’s blows, but if I disconnect the stepper, the fuse holds and the Gecko power light is on. The supply voltage is about 48volts just below the 20 times the motor rating as per the recommendation from Gecko.

The only thing I am not sure about is the way in which I have wired the windings to the Gecko so if one of the more knowledgeable people could help I would be most grateful.

Thanks

Andy

[CJL5585]

Andy,

You have your windings wired 180 degrees out of phase. I would also recommend that you wire them in Series instead of Parallel, due to current consumpion and heat generation within the steppers.

Red * Winding 1
Red/White

Yellow Winding 2
Yellow/White*

Orange* Winding 3
Orange/White

Black Winding 4
Black/White*


The above should be connected as follows for Parallel:

Red and Yellow------------------------- Phase A Gecko
Red/White and Yellow/White-------------Phase B Gecko

Orange and Black----------------------- Phase C Gecko
Orange/White and Black/White---------- Phase D Gecko


Use Below For Series Wiring:
Red----------------------------------- Phase A

Red/White and Yellow (Connected and insulated)

Yellow/White-------------------------- Phase B


Orange-------------------------------- Phase C

Orange/White and Black (Connected and insulated)

Black/White--------------------------- Phase D

Hope this helps.
Jerry

[audioandy1762]

Hi Jerry

Thanks for the reply.

I connected the wires as per the stepper motor supplier stated I think!

Quote

For parallel connection the start of the coils should be together
For series connection the start of the coil should be connected to the previous coil.

Just glad I fitted the fuse hope I hav'nt damaged the Gecko. I will try your wiring tomorrow and post my results.

Jerry will I loose torque if connected in series?

I built my power supply to supply the extra current for parallel.

Thanks Jerry for your help yet again its a steep learning curve but enjoying every minute.

Regards

Andy

[CJL5585]

Andy,

I wrote a long reply to your post, but the site messed up and lost it. I got a site not found error when submitting the entry.

Why don't you pick one method and wire it that way? If it does not meet your approval, then change the stepper wiring.

Let us know the results. I am sure others would also be interested in your results using a 48 VDC power supply.

Jerry

[audioandy1762]

Hi Jerry

Well you have done it again put a big smile on my face

Wired it as per your instructions for the parallel connection, hey presto the fuse held connected the pc to the breakout board, loaded the road runner file into Mach3 and away she went, played around with the speed settings no problem with speed and seems to be loads of torque I could not stop the shaft from turning with the Gecko limited to 2 amps.

I can now get the other motors wired up and tried, still along way off from a finished mill but with your help one BIG step closer.

Thanks again Jerry

Regards

Andy

[CJL5585]

The major problem I have with my 48 volt system running in series is heat from the stepper motors. After 3.5 hours of operation they begin to start missing steps because of the temperature. If I do not shut the system down, the motors will soon stall out from heat exhaustion. Excessive heat will de-magnetize the motors and ruin them.

Parallel Wiring -- (If the current is not limited as you are doing) it will cause even more heating. About 3X faster, so just watch the temp on the motors and drives.

Glad you are up and running.

Jerry

[audioandy1762]

Cheers Jerry for making the point, once all three motors are connected I will do some tests with various current ratings and post the out come on the zone.
This has now spurred me on to get my mill finished and up and running (not sure what I will do with it when it is running, but it should be fun building it)

Regards

Andy