Decoders for O Gauge

[binzauk]

A bit of advice if anyone could please.

 

I am in the progress of building a small O Gauge layout and will be using DCC. The locomotives I will be running will be small shunting type - Tower Models 'Pug' etc pulling only three to four wagons and only two or three locos on the layout at any one time. Would I be able to use higher rated decoders meant for OO gauge or do I need decoders meant for O gauge? I have a NCE PowerCab DCC system.

 

Thanks in advance for your replies

 

 

binzauk

[cromptonnut]

I've got a small O gauge shunter fitted with a OO sound chip and have had no problems so far with it. Also using a OO sound chip in a Bachmann 122 DMU and not had any problems.

 

Your best bet really is to put a meter between the controller and the rails, and see what the maximum (usually stall) current drawn by the motor is, and work from there.

 

The Bachmann 36-552 two function chip has a maximum current capability of 1 amp, for example. With low speeds and light loads you may well find that is sufficient.

 

Larger diesels like the Heljan 33 that are fitted with two motors - forget it - but for smaller locos you may well be ok with a OO chip. You can buy sockets and wiring harnesses and wire it up then plug the chip into that if you have room, or buy a non-plug chip and hardwire it yourself.

 

As for running several locos at the same time, that's more down to the capacity of the DCC unit rather than the chips, as the transformer provides layout power. Again, try "worst case scenario" with all your locos moving at the same time, you may find a booster unit is required as I believe the Powercab on its own can only supply 2 amps.

[pauliebanger]

A bit of advice if anyone could please.

 

I am in the progress of building a small O Gauge layout and will be using DCC. The locomotives I will be running will be small shunting type - Tower Models 'Pug' etc pulling only three to four wagons and only two or three locos on the layout at any one time. Would I be able to use higher rated decoders meant for OO gauge or do I need decoders meant for O gauge? I have a NCE PowerCab DCC system.

 

Thanks in advance for your replies

 

 

binzauk

 

It's the maximum continuous current you loco's motor will draw that is important rather than the scale. Quality 'OO' sized decoders can be had with up to 1.5A continuous rating (usually about 2.5A peak for short periods).

 

You will find these size format decoders easier to fit into smaller outline 'O' gauge, like your pug, than the larger scale decoders which are much bigger.

 

I use Zimo decoders which have an excellent reputation for features and superb motor control. I recently ran an 'O' gauge Lima 4F with a Zimo 'N' gauge sound decoder with no problem at all.

 

Kind regards,

 

Paul

[Gilbert]

Marginally off topic but possibly relevant as you use NCE - I have an NCE which is fine with a Lionheart Pannier with Sound (Zimo) but does not handle a Heljan Hymek with ESU sound fitted - it simply moves a very short distance then sits and ticks...so I assume the draw of two motors plus chip is too much as its fine on my Lenz system

Chris

[cromptonnut]

Heljan locos seem to be 'twin motor' which can on their own draw 2 amps, let alone the addition of sound, so yes that may be an issue with a Powercab.

[pauliebanger]

Heljan locos seem to be 'twin motor' which can on their own draw 2 amps, let alone the addition of sound, so yes that may be an issue with a Powercab.

 

 

If the Heljans really draw 2A for each motor then loksound XL will not be up to the job, as it only supplies 3A. Zimo MX695 will supply 6A, so plenty of margin.

 

However, there are lots of Heljan 'O' gauge locos running on LokXLs and the Heljan instructions show how to fit them. It is a pity that manufacturers do not state such things in their technical details section - if they had one, that is! Ha Ha.

 

Also, I have run different combinations of Heljan 'O' gauge Class 26, 37, 47, 55, and Bachmann Class 03, two at a time, using my NCE PowerCab without issue, and I know of several other people who do this also. So if one loco stalls on one layout but continues making sound, this does not in itself mean that Powercab is not up to the job.

 

The Lionheart pannier is more similar to the OPs needs, and that uses a 'OO' gauge decoder, I believe. (and very nice it sounds too!)

 

Kind regards,

 

Paul

[cromptonnut]

I meant 2 amp total, not 2 amp each sorry

[pauliebanger]

I meant 2 amp total, not 2 amp each sorry

 

No worries, now I look back at your post I see it was abiguous, not incorrect. I am sorry I read it that way. Ha ha!

 

Funnily enough, I have just taken a break whilst the Class 33 notching sound project I have been compiling is loading onto the decoder. Your sphere, I imagine?

 

Kind regards,

 

Paul

[cromptonnut]

Still waiting for my local model shop to find me a Heljan O gauge 33 in blue/yellow ends, then at some future point I'll be looking for an O gauge sound chip.

 

Quite liked the sound from the one Digitrains do on a Zimo chip but the jury is still out until I have the money.

 

Would be interested to hear more about, and of, your O gauge 33 sound project but perhaps that's best for another thread somewhere?

 

However, currently the layout is no more than an XTrackCAD file that is being tweaked, and until the 33 arrives I can't even go and buy the wood to build the baseboards (although 12ft x 2ft seems the likely size) so there's no real hurry my end. Although things might look good on the screen until I can test the theory full size on the floor then I don't want to commit to anything. Previous failures of 'test and measure twice, cut once' theory added to the expense of O gauge makes me want to be doubly cautious.

[binzauk]

Thanks for the replies and advice.

 

I'll do a test to see the current draw on my layout, but from what I am being told, I don't think I will have a problem using OO decoders in my locos as long as I don't try doing too much at once. On a small layout you can't do too much multi-tasking as your locos soon run out of track!!! Also, I am not looking at a sound option at the moment, but you never say never do you?

 

I suppose the ultimate solution is to buy and install the NCE power booster system which will give the 5A of current draw but probably an overkill for small shunting layouts and small locos.

 

I am also into 7mm Narrow Gauge and have a layout built (well, track laid and wired for DCC). I have fitted the locos I have with TCS micro decoders - more suited for 'N' gauge but they are superb for hiding in small NG locos. This layout is big enough to have a couple of trains moving at rhe same time and so far the decoders have been faultless.

 

binzauk

[cromptonnut]

On my project I am at most going to have three motored items - a Bachman 122, a Heljan 33 and a Ruston 165 shunter (kit built) and the chances of all three moving at the same time are next to zero as I only have a Lenz 90 and a Compact unit to operate everything anyway - although if all are on the visible part of the layout and sound fitted at least two might be 'ticking over', possibly all three - but, of course, being a small layout it isn't difficult to plan it so only two at most are running.

 

As it's also likely to be "single operated" - ie me - I can only do so much at a time anyway. Unless, of course, I can get SWMBO interested in things...

[pauliebanger]

Still waiting for my local model shop to find me a Heljan O gauge 33 in blue/yellow ends, then at some future point I'll be looking for an O gauge sound chip.

 

Quite liked the sound from the one Digitrains do on a Zimo chip but the jury is still out until I have the money.

 

Would be interested to hear more about, and of, your O gauge 33 sound project but perhaps that's best for another thread somewhere?

 

However, currently the layout is no more than an XTrackCAD file that is being tweaked, and until the 33 arrives I can't even go and buy the wood to build the baseboards (although 12ft x 2ft seems the likely size) so there's no real hurry my end. Although things might look good on the screen until I can test the theory full size on the floor then I don't want to commit to anything. Previous failures of 'test and measure twice, cut once' theory added to the expense of O gauge makes me want to be doubly cautious.

 

I notice Digitrains have a blue/yellow ends 33 in stock.

 

Paul

[cromptonnut]

I notice Digitrains have a blue/yellow ends 33 in stock.

 

Unfortunately I did some p/x to get a special deal with my local shop, which would work out somewhat cheaper for me than buying one from another shop. It's a shame really but that's just the way it is

[Pandora]

Bachmann do a 5 Amp Power booster, at a reasonable price, 

 

I guess that is a current amplifier,  and the output voltage to the track is  unchanged,  ie  Volts In = Volts out,  a Voltage gain of 1.

 

Is this unit compatible with other DCC systems?

[cromptonnut]

If this is the one you mean: http://www.ehattons.com/16808/Bachmann_UK_36_520_EZ_Command_5_amp_booster_with_transformer/StockDetail.aspx then "This booster can be used with any NMRA/NEM conforming DCC system. The booster comes with its own transformer" so one would assume so.

[Stringfingerling]

I've been advised people to check the maximum current drawn by my Tower Brass locos (stall current), prior to choosing a suitable sound decoder.   I'm a bit edgy about deliberately stalling them long enough to check the maximum current. Stalled motors heat up quite quickly surely? Has anyone any advice on doing this safely please?

[cromptonnut]

If you've got a meter set up to the track in the right way to measure current, then "stalling the motor" for just a few seconds - long enough to get a reading - shouldn't damage a motor.

 

Basically you just press down on the chassis until the wheels no longer go round - don't do full speed as that's not going to help matters.

 

My Bachmann brass 122 seems fairly happy with a OO sound chip although I'm not running flat out, uphill with a trailing load (12ft layout...) but larger locos, particularly steam, are probably going to be O gauge chips.

[Stringfingerling]

If you've got a meter set up to the track in the right way to measure current, then "stalling the motor" for just a few seconds - long enough to get a reading - shouldn't damage a motor.

 

Basically you just press down on the chassis until the wheels no longer go round - don't do full speed as that's not going to help matters.

 

My Bachmann brass 122 seems fairly happy with a OO sound chip although I'm not running flat out, uphill with a trailing load (12ft layout...) but larger locos, particularly steam, are probably going to be O gauge chips.

Thanks very much for that cromptonnut.  When you say  "don't do full speed", do you mean don't have the controller turned right up?  The maximum current through the motor is going to depend on the controller setting, so isn't it necessary to turn it up all the way under stall conditions?

[Crosland]

Stall current can be determined by ohms law from the applied voltage and the armature resistance. Far safer to measure those and then I (current) = V (volts) / R (Resistance).

 

It increases with voltage, so measuring it by stalling a slow moving loco requires the result to be scaled for the maximum voltage.

 

To be honest I would just measure the current when running on DC with a reasonable load over a range of speeds.

 

If the motor really does stall for any length of time you probably have other things to worry about, like a broken loco

 

Every motor is stalled momentarily when power is first applied, until it begins moving and the Back EMF increases.

 

Andrew

[cromptonnut]

If at 1/4 speed the "stall current" is close to the maximum rating of a OO chip, for example, then full speed stall is definitely likely to exceed the suitable current.  Similarly, if full speed no load is close to a chips limit then you need a bigger chip.

 

Of course, there are factors like lights, trailing load, smoke generator, gradient etc that will affect current so it's not an exact science as such but the basic principle is you want to leave capacity within your chip so as to avoid risking expensive blue smoke and a funny smell.