Re: [CAD_CAM_EDM_DRO] Blown Gecko 320..Strange noises from control???

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Wow, that's quite wierd! Do you have any new electrical equipment
there? Air conditioner, refrigerator, anything?
Sometimes when electrical equipment starts, especially larger motors, it
causes a dip in the line voltage.
When the line voltage comes back up, the filter caps are somewhat
depleted, and need to charge back up.
The lights, especially fluorescents, might flicker at the same time.
(It could actually be equipment at a
neighbor's house, if they are on the same transformer.)

/// Hi Jon, Thanks for responding. I do not have any new equiptment. The line is commercial 3 phase. I'm not sure if anyone has any new equiptment near me but, I dont thinks so. The overhead lights in my shop are not very responsive, they are heavy wattage and a voltage flicker would not be very apparent. Could a sudden dip in line voltage blow a driver? It just seems strange because the drive was at idle. I've peck drilled holes all day with Z driving the knee and the servo got a little warm and the Gecko was warm but not excessively so. ////

One other thing I can think of is if the main power switch is going bad,
and every once in a while it gets
an open circuit for a moment, then the current makes a connection again,
but the transformer has lost
excitation and has to sync to the line again. This can cause a big
"Boomp" depending on the line phase
at the instant it turns back on. The switch might get warm as a sign of
this happening. You could also
check the primary wiring for a loose connection.

/// Good idea, I'm going to check that. I'm also going to wire an incandescent 110 volt bulb outside the enclosure to the transformers primary to see if it flickers when the noise happens. It will be right in front of me and more apparent. ///

It could also be the bridge rectifier may be going out. Usually, those
do no go intermittent first, but
anything is possible.

One last possibility is that one of your motors has developed an
intermittent short to ground.

/// My motors are practically new and sealed up water tight with O-rings and I had them apart doing the encoders last year and all thats in there is two magnets an armature and two brushes and the wires were routed properly. The encoders are in a seperate sealed section altogether. The motor seems like a weak suspect but, I wont rule it out.





If so, you
will lose another Gecko soon! (I kind of doubt this, as a short to
ground will pop a Gecko pretty quick.)

////my Z drive driving the knee I've noticed since my retrofit it has been this way. At idle the motor dithers or slight buzzing vibration, It will stop and start again and gets just marginally warm. The knee being heavy it stop wherever it wants to rather than float to rest like X an Y. Is it possible that the drive is not settled in perfectly and is continually trying to adjust causing a problem? I'm not sure if thats what it is but it acts like its trying to find Neutral position. X and Y do not do this.




However, if the Gecko supply is mostly floating, but there is a weak
ground path, maybe through the
breakout board, parallel port cable, computer, power cord anc back to
the machine's ground, it might
not blow the Gecko right away. When the short goes solid, lots of stuff
will smoke, cables will melt,
it will be a big mess. I hope this is not what is really going on.
Darn strange, I wish I could actually
hear it do it, and see what the machine does at that moment. Does it
twich at all?

///No twitch at all, to be on the safe side I zero'ed out my handwheels and payed close attention all day to seeif there were any discrepancies and none were observed.



That might be an
indication that the DC voltage dipped at that moment.

/Sounds like hitting a piece of sheet metal with the bottom of your fist. I know it's weird. I think the voltage dip from the line or possibly my primary wiring as you've suggested may be the culprit. In the morning I'm going to go over it with a fine tooth comb for a possible short, I've been really busy lately and havent had alot of time to clean and chips are all over everything. Jon, If they dont already make one, what would be great to have is a small device someone could plug into a receptacle and monitor voltage over a long period of time. It could monitor a certain bracket of voltage and report when the line dropped out of or exceeded this bracket and generate a reviewable record. If I had that I could just leave it in a receptacle and come back later and see what that voltage profile has been and see if the noise occurences correspond to the device's report. Lcd screen scroll through the events..haha, I dont ask for much.

Ron







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