Re: [CAD_CAM_EDM_DRO] Re: BP retrofit yaxis drive burnup- follow-up FIXED!

----- Original Message -----
From: "Keith Clark" <mail@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, April 09, 2005 1:46 PM
Subject: [CAD_CAM_EDM_DRO] Re: BP retrofit yaxis drive burnup- follow-up
FIXED!


>
>
> Well Guys I finally found the most recent bug. There was an
> apparently defective terminal block on the x axis Gecko. After much
> exchanging of parts I finally isolated the block, cap or wires.
> Once the block was change everything operates the best yet. I have
> rapids that are scary and no stalling. Sure feels good, I just hope
> it will last!!
>
> Keith
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
>> Keith Clark wrote:
>>
>> >Ron, we need to compare notes to see if there is a common
> pattern.
>> >Mine takes some time to burn also, but I hope my problem was
> having
>> >the relay to turn off and on the powersupply on the DC side
> instead
>> >of the AC side. Now I can't get the x axis to move properly...
> I
>> >am going to drop to half winding mode and lower current to see if
>> >that helps in the long run.
>> >
>> >
>> If these Gecko drives last several months, and then die, I would
> suspect
>> it is
>> a heat related problem, or possibly the current inrush is
> degrading the
>> internal
>> capacitor. It takes so many inrushes to wreck that cap, and then
> the
>> uncontrolled
>> voltage spikes destroy the power FETs. If these problems are all
> on systems
>> using a relay on the DC side, then that seems like the diagnosis.
> If
>> some of these
>> recurring failures are on systems without the relay in the DC
> side, then
>> heat of some
>> sort has to be it. It has been noted by several people that the
>> internal cap
>> in the Gecko drives runs very hot if even half a foot of wire runs
>> between the main
>> filter cap and the drive, and no external cap is used right
> outside the
>> drive.
>> Most of the pedestrian caps are rated for a few years life at 85 C
> core
>> temperature.
>>
>> (My PWM servo amps have a fairly expensive 2.2 uF film capacitor
> in
>> parallel with
>> the internal electrolytic cap for exactly this reason.)
>>
>> Jon
>
>
>
>
>
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