Re: [CAD_CAM_EDM_DRO] BEI encoder replacement

Sounds like a good idea to replace with an LED. No reason it has to
stay an incan bulb.

Danny

On 10/9/2010 2:30 PM, Dan Mauch wrote:
> Here is how I fixed my BEI encoder with a bad incandescent lamp
>
> Taken from my web page
>
>
>
> While disassembling the Y axis I noted there was a BEI incremental encoder
> mounted between the ball screw and the servo motor. I removed it and tested
> it. There was no output from channel A, B or the index. I called BEI tech
> support and relayed what I had found. They asked me how much current it
> drew. It was 70 MA. They told me that was too low and I would either have to
> buy a new one for $400 or send it in for repairs and that repairs could cost
> up to $200 if repairable. After thinking about it for a while I decided that
> I could easily replace it with a US digital encoder for a lot less. But I
> wanted to do a few more checks on the BEI encoder. I check quite a few items
> and then realized that it must be the light source in the encoder. I cut one
> of the leads and sure enough the encoder light source was open. I assumed
> it was an IR LED. I removed it and noted that this little light was only
> .125D and about .187L. I looked at the circuitry and was surprised to see no
> dropping resistor or the LED. It was wired directly to the +5 terminal and
> ground. Upon closer examination I could see that there was a portion of a
> filament inside the miniature bulb. It was an Incandescent Lamp!.
>
> I went through my catalogs and found that Chicago Miniature makes hundreds
> of different incandescent miniature lamps some of which were 5 volts. I then
> was able to find that Mouser electronics carried this replacement bulb for
> $1.60 . I needed to order some other parts for various orders I had so I
> went ahead and ordered it. When it arrived I installed it and powered it up.
> I could see the light on and when I connected my scope I could see that all
> the channels were working properly. These little lamps come with different
> filaments so you can get them with 10,000 -40,000 hrs of life. Failure
> analysis of the Y axis was probably caused by the encoder lamp burning out.
> This most likely caused the Y axis to run uncontrollably into the column
> causing the Y axis servo amp to burnout, blow the fuse and fractured the
> ball nut flange.
>
>
>
> www.camtronics-cnc.com
>
> dmauch@...
>
> Low prices on Gecko drive, cases , sepper and servo motors.
>
> 3d scanner
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
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