Author Topic: LM3-S voltage issues, then motor overload -- why?  (Read 125 times)

ON28

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LM3-S voltage issues, then motor overload -- why?
« on: July 13, 2020, 03:32:41 PM »
Today ran my trusty Atlas GP-7 with an LM3-S and KA-3, when voltage suddenly decreased, eventually down to 3 and change, so I shut down. Found a screwdriver partially on the rails, though the PSX circuit breaker did not trip. Restarted and the loco ran a bit, but again showed fluctuating voltage up and down, then to 3 and change again. I tried auto-resetting max motor current (530 Mah) and it reset to 630. Tried to run and got a Motor Overload alert. I ran other locos and had no problem, though this same situation weeks earlier occurred with a Kato F3/LM3/KA4 after it ran on underpowered track, which I have yet to fully investigate. Any suggestions here? Are my modules damaged, or can they be reset? Thanks!

William Brillinger

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Re: LM3-S voltage issues, then motor overload -- why?
« Reply #1 on: July 13, 2020, 07:00:51 PM »
Can you take the KA out and try it again?
- Bill Brillinger, RPUG Admin

Modeling the BNML in HO Scale, owner of Precision Design Co., and RailPro Dealer.


Alan

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Re: LM3-S voltage issues, then motor overload -- why?
« Reply #2 on: July 13, 2020, 07:10:45 PM »
Also put a voltmeter across the rails near the loco when it is running correctly and again when it is running incorrectly. Reading same voltage as shown on LM both times?
Alan

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When I was a kid... no wait, I still do that. HO, 28x32, double deck, 1969, RailPro

ON28

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Re: LM3-S voltage issues, then motor overload -- why?
« Reply #3 on: July 13, 2020, 09:25:58 PM »
Turns out a quick look under the hood revealed one wire to the KA had come unsoldered. Fixed it, and added heat shrink to secure. The auto-test set voltage at 550 ma and the unit was released back into revenue service! Thanks to all for the help!