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Discussion Starter · #1 ·
I bought a Bemo GE6/6II yesterday. For those not in the know, the prototype is a Bo-Bo-Bo slightly articulated (vertically) for hauling heavy trains (14 double bogies not uncommon) in the metre gauge network in south eastern Switzerland. The model is HOm.

The model actually has two motors - its haulage capacity is likely to be very impressive as it is quite heavy. The model shop which sold it me obviously didn't realise there were two motors as they only sold me one chip.

I normally use Lenz mini decoders as there isn't usually much room in an HOm loco. One decoder won't be powerful enough to drive two motors without risk of burnout so should I be installing two decoders? Alternatively, Should I install a more powerful decoder to drive both motors in parallel? There would be room in the loco in this case.

My instinct is to install two Lenz minis and set them both to the same address. The alternative would be to set them to different addresses and program the loco as permanently double headed.

Advice, please.
 

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DT
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I have thought about the same issues when looking at control options for a twin motored Garratt. The best option seems to be one decoder with a higher capacity. There are quite a few around designed for larger locos. Zimo have a very complete range and you can find one there that will handle the current for your two motors plus manage any functions that the loco may have.

If there is no space for one big one, you can use two smaller decoders, either on the same address, but that might cause problems with functions, or set up as a consist. Using a Lenz control system, the consist can be controlled by it's own special address or the address of one of the locos in the consist so addressing isn't an issue. Also the functions of the individual locos can still be activated, so if you build the consist and run it from one of the decoder's addresses, all the functions of that decoder will work as normal. If the loco has more functions that is available on one small decoder, you could assign other functions to the second decoder.

Is this the loco?



I notice that is is available in green too:

 

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Discussion Starter · #5 ·
Thanks for the replies.

Yes, Doug, you've produced the correct photo for the class.

Now I've got the loco home and opened it up there isn't much room. The chassis is in two halves. Each half has its own PCB connected to each other as appropriate (eg, common pickups). The model is designed to run DC. There is a small piece of PCB (on each half) which when removed can be replaced by a decoder. I'll be taking this option.

It would be possible to create more space by either:

removing the PCBs and wiring direct to a single decoder, or,

removing some of the lead weights attached to the chassis.

As I say I'll be using two decoders, using the PCBs provided by Bemo, and keeping all the adhesion weight.

Unfortunately I've not had much time this week, and it's off to see the prototype next week, so connecting the decoders will have to wait till the end of the month.

Once again , thanks for the help.
 

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>it's off to see the prototype next week
You lucky chap! Have a good time and take some photos to share when come back - pretty please?

David
 

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Discussion Starter · #8 ·
An update. I finally got round to getting this loco working.

Further obsessive detail: most Bemo locos have function control for forward and reverse driven by the white and yellow wires. The blue is, so far in my experience, always unused. Close examination of the PCB showed that the white and yellow wires went nowhere. Not too much of a problem. On the prototype one of the rear lights is always on (observation limited to RhB and SBB only - will do more research next time). Bemo light both lights on the end of a loco from one LED so single control of one light is not possible - you're always going to be 50% wrong!

I connected the motor and track wires on one decoder - lo and behold, all the LEDS, forward and reverse are permamently on. No function control. It would be possible to rewire but this is a compromise I'm prepared to accept at the moment.

I've installed the second chip for the other motor and programmed them both to the same address. The loco runs superbly.

By the way, any one wanting Swiss prototype pictures send me your email address and requirements. I'll do my best to oblige. The photos are all large format - ie you'll need to be on broadband.
 
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