"Motor Overcurrent" error, maybe solved

[zr1rob]

it's only maybe solved because this solution isn't proved long term, but it did solve the problem of 'motor overcurrent' error popping up on the HC2 and shutting down the loco, till power reset.

Only one loco with this error: the electric G scale Accucraft GS4 has a huge Pittman motor, but it only draws ~1.5A when running normally. However, the current spike during initial movement was too much and thus the error. Put an "Inrush Current Limiter" inline with a motor lead, as well as raising the 'starting speed' for the loco solved the problem to the point the loco can be used regularly without errors. I used an Ametherm SL32 10015 Current Limiter Inrush 10 Ohm 15a. BTW: this loco is battery powered.

[gregeusa]

The Pittman motors used in Accucraft are technically servo motors, used for rapid movement.

To generate quick and low rpm torque they draw big spikes of current from stopped.

Your solution is the right one, although I'll bet even a 5 or even 1 ohm resistor would have done the trick. You might have issues pulling heavy trains and the 10 ohm resistor "eats" too much of your voltage (voltage = rpm in an electric motor)

[zr1rob]

hi greg -

there was a lower value ICL that I tried "Ametherm SL22 5R012", it only handles 12A, but is 5ohm, did not work. The loco would tease running, but die. So the initial current inrush must be over 12A.

so that's why I went with the big gun. Rob Pira

[gregeusa]

Wow, well that is a good datapoint. I suspect the RP decoder is tripping much earlier than (in my opinion) is needed.

So, probably tripping at rated current, not double as often is done.

I can understand the conservative "restriction", as the model 3 decoder was not up to the G scale locos in general..

which decoder is this, the 4 or the 5?  Can't be the 5 or its not living up to it's rating.

[zr1rob]

4 in the loco now, but it behaved the same halting way with a 3.

BTW: there's a 7000mAh 6S LIPO in the tender. There's no hysteresis when highballing this baby

[gregeusa]

Not denigrating the product, but the overcurrent detection circuit/algorithm needs improvement.

It needs to be "programmed" like a slow blow fuse, not an immediate trip, needs to take consideration of overcurrent into account.

Many many decoders have no issue with these Pittman motors.