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Discussion Starter · #1 ·
Does anyone have any experience troubleshooting one of these? There is a Multilin 269 for the motor control and the MTM-120 for current, voltage and power output to a PLC..
The PLC display has been reading 0 for quite sometime. Did some preliminary testing and found I had 60 vac on the power input terminals. That told me that one of the PT fuses could have failed. We had an outtage yesterday and I checked all the fuses. They all read about 36 ohms, which is what they read during the last PM on the starter. I removed them and meggered them to 1 KV and they showed good. One of the fuse holders was a little loose, so I squeezed it a little and re-installed the fuses. Re-energized and the control voltages were up to 120 volts. Once the motor was restarted I checked with my meter at the PLC and was getting 0 mA to the PLC Analog Input. I measured from the + to ground and still had no current. I went right to the MTM output terminals and was getting 0 there too..
I tried finding a manual for some troubleshooting and was unable to... The unit is original to the site (around 1994)... Would it be a safe bet that it is giving up the ghost and its time for a replacement? Is there a fuse or something that may have died inside it and it is an easy repair? Just ran out of time before it came the motor came back up..
Thanks in advance....
Glen
 

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Discussion Starter · #3 ·
You would put your meter in series in order to measure mA.
I was in series to the PLC input (+ in from MTM and + out to PLC).. Series from the "+" on the MTM to gnd at the PLC (Checks for a bad point on the card).. Series at the MTM with the + to the PLC (Broken wire?).. Series between the + and - at the MTM, with the PLC wires unhooked (Broken wire??)...

Shields are grounded at the MTM only...
 

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Sorry, I misunderstood how you were measuring. Without being there, I would say that if you are measuring, 0 mA on the output of the MTM (terminal 58 and 59) I would probably say that the MTM is bad. Here is a link I found that relates to the MTM you referenced:

http://www.gedigitalenergy.com/products/manuals/269p/269pman-e4.pdf

I skimmed thru it real quick, it appears that the 4-20 out can be set for different things. Maybe someone was playing around and messed up a setting....
 

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Discussion Starter · #6 ·
Sorry, I misunderstood how you were measuring. Without being there, I would say that if you are measuring, 0 mA on the output of the MTM (terminal 58 and 59) I would probably say that the MTM is bad. Here is a link I found that relates to the MTM you referenced:

http://www.gedigitalenergy.com/products/manuals/269p/269pman-e4.pdf

I skimmed thru it real quick, it appears that the 4-20 out can be set for different things. Maybe someone was playing around and messed up a setting....
Thanx.. the manual was for the 269 Multilin, and terminals 58/59 aren't used. The MTM is hooked to Term 84 and 85 and is on RS-485 and provides 3 analog outputs to the PLC..

https://www.google.ca/#q=multilin+mtm-120+manual
 

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The persistent low voltage to the PT inputs likely also meant it was fluttering on and off at some point and over heated an A/D converter inside, which may have damaged everything else connected to the DC side. You could tear it apart and look for cooked parts on the PC boards, but I wouldn't bother. It's likely not repairable anyway or would cost too much to fix.
 

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Discussion Starter · #8 ·
Thanx for the reply JRaef...
I talked to the client yesterday and since this is the last 269 they have in use in this area, they are most likely going to upgrade to a 369 and use it's outputs to the PLC, depending on recommendations from their Medium voltage service folks..
 
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