Help !! Regarding Running Playmobil Motor Blocks DCC

Gareth

Gareth

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I have recently built a loco using 2x Playmobil motor blocks . When running in Analogue they are great . Having wired them up to dcc with an Massoth Xl 4amp decoder they work great but they have a tendency to yoyo at slow speed, could anyone offer any advice ! do they need some fine tuning and if so what to do and can it be cured !!
 
Assuming you did not see the problem when running on analogue..

I would check the quartering first.. Even one tooth out can make a difference.

Then look at Load Control, Back EMF, and even PWM frequency. - Do check for themotor(s) running warm, if you make changes.

PhilP
 
Thanks Phil quartering not an issue its a diesel but will have a look at the other suggestions . I did wonedr at back EMF and PWM Frequency thanks
 
Yes, it's the BEMF going a bit nuts, try turning BEMF off if you can. If it was quartering it would happen no matter what, and it was good on track power before DCC added.

One thing to also check is the nominal voltage of the motors, vs what you are supplying, you might be supplying a lot more voltage than needed, and that can make some things work funny, i.e. draw a lot more current, and that can affect BEMF sensing logic in the decoder.

If the decoder has a BEMF "training" function try that...

Greg
 
I have used a Playmobil motor block in a Tram conversion. It does not like more than 14V and I suspect that the Op is using a much higher voltage hence the problem
 
I'd agree, while technically a higher voltage alone should not mess up the BEMF, it could give feedback that confuses the BEMF circuitry. I won't go into the technical details, but a voltage dropper (made of diodes) to limit the motor voltage to 14v would be a good idea, if nothing else to help reduce heating, and perhaps overcurrent to the brushes.

you (the OP) can search my site for "diode dropper" for a circuit of diodes and a full wave bridge.

Greg
 
Thanks to all of your advice ! Problem was sorted today , loco is now a very nice runner !1 Thanks gentlemen !!
 
I re tweaked the load control for acceleration and de- acceleration has worked a treat and loco motors not getting hot very pleased
 
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