County Gate and River Avill

[pilotfriend]

A new diesel electric has entered service, an articulated version of an Armstrong Whitworth, frets supplied by Bernard Taylor. It runs on two Bachmann class 08 chassis controlled by a Digitrax 143 chip. It is a very powerful and smooth runner.
JdF

[JulienW]

Very nice John ;)

Just out of interest about the DCC-edness of River Avill, I had always thought that when it came to DCC it was a case of one chip per motor, so ig you had a Garratt or somthing with 2 motors you needed 2 chips (probably both assigned the same address).

I'd be interested to know if you have, as your post suggests, used a single chip, and if you have how this is wired to the motors - essentially are the motors in series or parallel. I'd also like to know if the current draw from the pair of motors is a factor on which chip is used - i.e. some chips may not be up to the job of running a pair of motors.

I have a Sierra Leone Garratt (a Paul Windle build) that I'm planning to chip at some point (this will be a long-term project) that uses a pair of Bachmann (old style) 2-8-0s and if I can get away with using a single chip the job may work out cheaper than using 2.

Thanks in advance.
Julien.

[pilotfriend]

Hi Julien

You can use a single chip provided that the two power bogies are identical. They should always be wired in parallel. Of course, with 'Avill', the two chassis are in opposite direction so it is necessary to reverse the wires to the motor on one. Likewise, the chassis are live so one must use an insulating link between the units and the corridor is mostly plastic.


here you can see the way it is wired. The white yellow and blue wires are for the reversing lights.

The current draw on these small chassis is low indeed and I have with success used the smaller output DZ125 chip to power the two Mallet power bogies....the slightly large DZ143 is a better choice but would not fit in the Mallets.

When linking two locos which are scratch built, one cannot expect them to perform equally. In that case, I chip each one and then programme the chips using speed steps so they both perform equally. This can easily take a day BTW. If they are to be used as double headers, I do link the locos pickups electrically as well. This vastly improves reliability.




these two took three days to programme so they worked together!

best
JdF

[JulienW]

Thanks for that John :)