Converting my DC class 141 to DCC

[Mikemasey]

G'day all from down under.

I have a Hornby Class 141 sprinter in DC and would like to convert it to DCC.

Each of the two units have a motor and are coupled to each other via a pin and socket joint device.

Do I have to electricaly isolate each unit or am I able to parrell each motor from one DCC source?

Basicly has anyone a diagram I can use please.

Many thanks,regards,

 

Mike.

[jane1707819582]

hi mike 

i would suggest using two decoders and isolating each motor, but i would be tempted to remove 1 motor and try i'ts pulling power with just 1 ,

i suggest 2 decoders because the back emf from the two motors may be slightly different causing amok with one decoder ,

[Chrissaf]

Don't particularly want to stick my head above the parapet to be shot at, but I will risk being shot down in flames all the same.

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It's just that I have never ever come across any Hornby DMU that is fitted with more than a single electric motor. Usually the rear motor car is a dummy without a motor. The electrical connection between the coaches could be just for lighting. Of course, two powered cars might have been put together from two train packs to create an unofficial double powered unit.

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One of the reasons that Hornby would have been unlikely to create a dual powered DMU from the factory is due to the issue of synchronising the motors. One easy way to tell, is that the front motor car will be significantly heavier than the rear dummy motor car. Do your two motor cars weigh the same?

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As I said, this is just an opinion based upon previous product observations and will be happy to be proved wrong. Now if you were to tell us the R stock number, then some research could be done.

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Just assuming that there is indeed two motors for a minute. Then one would assume that each powered car would have its own wheel pickups. Thus two decoders, one per motor, would be the easiest conversion. To only have one decoder raises certain issues. The total current of two motors in parallel would need to be within the supported current spec of the single decoder. And as Jane says, the back EMF detection used by the decoder to regulate motor speed could be compromised if two motors are wired in parallel across the decoder output. Then all the wheel pickups would need to be routed to the input of the single decoder. That would involve some significant wiring surgery and additional wiring to be installed between the cars. Two motors each with a decoder of its own, would simplify the wiring modifications needed, and the two decoders could then be configured as a 'consist' and have the motor control algorithm CVs adjusted to give balance to the motor responses in the way that they operate.

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[Going Spare]

Early versions of the class 142 were produced with a motor in both vehicles, and (from memory) no traction tyres.  Later versions had only one motor (and traction tyres), with and without electrical feed from the unpowered vehicle via the coupling. 

GS

[Mikemasey]

Thanks for all the answers. 

 This unit arrived unboxed so no other info is availiable. How ever there are defo motors in each and no traction tyres.

I didnt realise about the motors until a friend pointed out that his only had one moter per two cars!

So it looks like a decoder in each or make one of the units into a dummy only depending on how it pulls with just one motor.

 

Thanks again.

 

Regards,

 

Mike.

[96RAF]

I would go down the two decoder route and give them both the same address.

[Ruffnut Thorston]

These are the "Pacer" units (not "Sprinter" or "Super Sprinter" units, which are conventional bogie cars), class 142, and consist of two 4-wheel cars.

 

Sometimes known as "chewy trains" after the chewy mints of the "Pacer" name!

 

Or "nodding donkeys" after the movement imparted to the head of the driver, and possibly "customers", by the movement of the train!

 

On the model, the motor drives only one axle of the power car, or cars. The installation is reminiscent of a Scalextric car motor!

 

So, only two driven axles with two motors, and just the one driven axle with the one motor.

[Robby_50]

I've put decoders into 4 different pacers.

One was a new Chinese made Arriva liveried model that has a socket at one end so a direct pin decoder meant no wires to be seen.Eay-peesy!

One was a single motored older Chinese made model with traction tyres and power connections between coaches, so I used a single decoder hard wired in the end toilet compartment of the powered coach after cutting away part of the rear floor.

The other two were UK made with 2 motors and no power connections between coaches. In one I hard-wired a single decoder (Gaugemaster not Hornby, as it needed to cope with 2 motors )  in one coach and wired to the pickups and motor feed to the other coach ( thus 4 wires fixed with black tac across the coupling ). In the other I used a Hornby decoder in each coach, but you really need to connect the pickup wires from both coaches together ( 2 wires across the couplings ) as I found the pickup's not very reliable. If I do any more I shall just use 1 decoder and wire across just because it saves the cost of the second decoder.

Taking out a motor doesn't help, as I found that a single powered axle without traction tyres struggles to move the 2 car unit.