Who's The Troubleshooting Expert?

[freak_brain]

I'm confused as to what happened. Maybe one of you fine fellows can help as I'm not an electronics guy.

Ok, I wire all of my electronics. I'm using gecko G201's. I checked voltage everywhere before wiring to my little tropical creatures. I hooked up the one drive I was going to use for "X" axis and everything is fine. Motor runs around like a crazed animal. I then wire an on/off switch and hook up "Y" axis. Turn my drive box on, started the software in my pc and then I hear sizzling. I turn everything off and smoke comes out of the "Y" axis gecko and it's very hot. I checked my wiring and everything is correct. I take the bride rectifyer to work (it was also very hot) and it's ok. I remove power from all three geckos and I find out that my voltage is now 78 volts coming out of my capacitor(should be around 48 or so). When I remove the wires from the DC side of the rectifyer I have 51 volts on the DC side. When I hook the wires back to the recifyer I have 78VDC. Now, none of my geckos work. My heat sink fan is the only thing working now, lol. Can someone give me some advice as to what my problem may be?

I'm wondering....

Is there any way possible for me to have hooked my on/off switch up incorrectly that would have caused more power to go to the rectifyer, then to the capacitor, and the capacitor is just storing the energy causing the voltage to be to high?

Here is how the power supplies are wire. The one on the right but without the 12V side

http://www.wc101.com/JFettig/mill/PSscematic1.jpg

Any assistance would be appreciated!!

-Allen

[Al_The_Man]

The fact you are getting 51 AC converts to 72DC which is close to your final DC output, so I would guess that your AC is too high, if you measured the AC into the rectifier you should have around 35vAC allowing for bridge drop for 48vDC.
Did you swop the primaries over when you wire the switch in as you may have gone from a 'buck' condition to a 'boost' condition by wiring them out in phase and prior they may have been out of phase.
Al

[freak_brain]

Actually Al, now that I think about it 78V is still within the geckos working limit. So that shouldn't have done any damage. With a needed input of 10-25 the motors rated voltage and the motors are rated at 4.3V, thats 18 times the rated voltage so that should have been ok. Right on the high side with both but still within the acceptable limits. So now I'm still wondering, what is wrong....hmmmmmm

Thanks for all of your help Al, I certainly do appreciate it.

-Allen

[freak_brain]

"Did you swop the primaries over when you wire the switch in as you may have gone from a 'buck' condition to a 'boost' condition by wiring them out in phase and prior they may have been out of phase."


I'm not sure what this means. The switch is on the AC side...turns on my power supplies

-Allen

[JFettig]

Do you have the gecko drives fused with fast blow fuses?

Also, with that scematic, the ac voltage comming out of them is going to be aproximatley 48v but the rectified and filtered DC voltage will be around 67v.
Do you also have a 470uF capacitor on the input of the gecko drive?
What size capacitor do you have in the power supply, uF and voltage?

Jon

[freak_brain]

Well, stupid me I didn't have them fused. I will now.

20,000uF and 80V capacitor on the power supply and yes I do have the 470uF capapcitor on the input side of the geckos.


By the way, how do you check a capacitor, other than sticking your tongue on it??

-Allen

[Al_The_Man]

Originally Posted by freak_brain "Did you swop the primaries over when you wire the switch in as you may have gone from a 'buck' condition to a 'boost' condition by wiring them out in phase and prior they may have been out of phase." I'm not sure what this means. The switch is on the AC side...turns on my power supplies

It means that if you have transformer winding is series, both transformers have to be in phase, otherwise one series winding will subtract from the other instead of adding to.
You can get this effect by swoping either one of the primary windings, or one secondary with respect to the other.
Al

[freak_brain]

Oh, Ok Al...I doubt that is possible since I had that wiring done and did not mess with it to wire in the switch. I just had the two leads coming from the power supplies to the switch and before that I had the same two leads going to a plug. So I believe that is ok. It's the same now and it is working fine to the capacitor.


-Allen

[ger21]

Did you have your motors wired correctly? That will fry a Gecko also. Although you said the X did work at first, so maybe that's not it.

[freak_brain]

ger21

I think that's what did it. I'm not exactly sure how but that is what I'm leaning towards because everything else looks correct.


Thanks All, I appreciate your help
-Allen

[Mac T. Knife]

Whose motors were you using?