DCC and coreless motors

[Siennaark]

I purchased a N gauge Railbus off eBay, its on a Kato chassis with a coreless motor. I sent it off to be DCC hardwired, fitted with a Lenz Silver Mini Decoder. It came back and worked for about a week then it became unresponsive. Strangely, when I reset it 8/8 it moves along the programming track a few inches in response to the programming. Similarly, when altering cv values, it moves along the programming track. But when placed on the Main Track absolutely dead. Anyone got any ideas?

[melmerby]

9 minutes ago, Siennaark said:

I purchased a N gauge Railbus off eBay, its on a Kato chassis with a coreless motor. I sent it off to be DCC hardwired, fitted with a Lenz Silver Mini Decoder. It came back and worked for about a week then it became unresponsive. Strangely, when I reset it 8/8 it moves along the programming track a few inches in response to the programming. Similarly, when altering cv values, it moves along the programming track. But when placed on the Main Track absolutely dead. Anyone got any ideas?

Have you checked the address?

A full reset will change the address back to a 2 bit address of 3

Edited February 21 by melmerby

[Siennaark]

Yes, I realise that thanks. I've recently upgraded my controller to a Z21 so I can now read CV settings as well as write them.

[melmerby]

Did you get the manual that comes with Lenz decioders?

If not you can see here

Lenz decoders have an error reporting CV, if you have the manual and find which CV it is, you can see read that and see whether it has an error for some reason.

 

The fact that it still responds to read and write commands suggests it isn't totally dead.

[RFS]

CV 30 is the one that will report errors and should be 0 if all is OK.

 

Are you sure it's the decoder that's the problem and not the coreless motor?

[Nigelcliffe]

15 minutes ago, RFS said:

CV 30 is the one that will report errors and should be 0 if all is OK.

 

Are you sure it's the decoder that's the problem and not the coreless motor?

 

There's no issue with coreless motors and DCC on commonly available decoders.   (There may have been an issue 25 years ago on a handful of very early decoder designs which used very low frequency control of motors.  Which is just like analogue DC use where there are some DC controllers which use low frequency control which are bad for coreless motors....).

 

 

As the model responds under programming,  I'd look for things like: 
a)   is the correct address being called up ? 

b)   is the model in a decoder consist (CV19 set to anything other than zero)   or does the control system have it in an internal consist (so routing instructions to another address).  

 

It doesn't sound like an electrical or motor issue if the model moves when programming is happening.   

 

 

 

[melmerby]

1 hour ago, RFS said:

CV 30 is the one that will report errors and should be 0 if all is OK.

 

Are you sure it's the decoder that's the problem and not the coreless motor?

Lenz decoders default to High Frequency control. (approx 23KHz)

[Siennaark]

Thank you all for the replies. Unfortunately I have messed up. CV30 = 4. I read another thread that  setting CV30 to a value of 128 turns off the short sensor completely. This made the chip get hot and short circuit. Of course meant that I couldn't reset the chip as it was constantly shorting out. I'll take it to the experts. 

[melmerby]

19 hours ago, Siennaark said:

Thank you all for the replies. Unfortunately I have messed up. CV30 = 4. I read another thread that  setting CV30 to a value of 128 turns off the short sensor completely. This made the chip get hot and short circuit. Of course meant that I couldn't reset the chip as it was constantly shorting out. I'll take it to the experts. 

Does the decoder still respond to programming or has it now died completely?

If the first can you try and write 0 to CV30?

This may clear the fault code

[TWG]

I hope that I am not misunderstanding something, but I find your posts confusing.  Setting CV30 to 128 is not mentioned, as far as I can see, in the Lenz instructions, but how did the CV get set to that anyway?  How do you know that it did, if you did not do it? You say CV30 shows 4.  Then you say that the setting of 128 made the chip get hot and short circuit so you could not reset it, though in your first post you say that you did reset it. Even if the overload protection was turned off, this would not of itself make the decoder overheat unless there was a fault causing this.  You seem to be conflating overheating and a short, which have different fault codes.  If there is a motor short the lights on the railbus (if it has them) would flash, but that cannot be the problem because there would be no reaction when you tried to set CV values.

 

I think that, if we are to have any chance of helping you to solve the problem, you  need to provide a more coherent account of events.

[melmerby]

1 hour ago, TWG said:

I hope that I am not misunderstanding something, but I find your posts confusing.  Setting CV30 to 128 is not mentioned, as far as I can see, in the Lenz instructions, but how did the CV get set to that anyway?  How do you know that it did, if you did not do it? You say CV30 shows 4.  Then you say that the setting of 128 made the chip get hot and short circuit so you could not reset it, though in your first post you say that you did reset it. Even if the overload protection was turned off, this would not of itself make the decoder overheat unless there was a fault causing this.  You seem to be conflating overheating and a short, which have different fault codes.  If there is a motor short the lights on the railbus (if it has them) would flash, but that cannot be the problem because there would be no reaction when you tried to set CV values.

 

I think that, if we are to have any chance of helping you to solve the problem, you  need to provide a more coherent account of events.

Yes, I'm confused like you are🙂

There is a topic on an US forum where one person says you can use CV=128 to turn off short circuit protection. Why would you ever need to do that?

There is no mention where this information came from.

AFAIK, as standard and after a reset, the overload triggers are active and if there is a problem the decoder will shut down with a CV 30 value denoting what triggered the shutdown.

You should then be able to reset CV 30 by programming it back to 0, after which, unless the decoder is damaged, it should work normally again.

Edited February 24 by melmerby

[Quadrille]

If there was an issue with the motor then it wouldn't move along the programming track...it sounds more like a programming issue.

If "there's no issue with core-less motors" then I would like to know why three New motors failed Oxford N7 after barely two hours running from each of them.   One was the original and two replacements.   The fourth motor is different and has six holes in the drive-end and two larger holes in the opposite (electrical-connection) end, presumably for ventilation.   The latest motor has so far lasted 12hrs and cost £5.00.

[TWG]

Nigel Cliffe's statement above that there are no problems in principle with coreless motors is correct.  Over the years I have bought a number of locos with such motors and have retrofitted others with high quality ones (Faulhaber and Maxon).  I have never had a failure.  It looks to me as if Oxford, probably to keep costs down, bought some cheap motors of dubious quality.  The fact that your latest motor is different could suggest that they have realised their error.  I hope that the new motor is satisfactory, but £5.00 for a coreless motor does not to my mind suggest a top quality item

[melmerby]

On 24/02/2024 at 17:44, Quadrille said:

If there was an issue with the motor then it wouldn't move along the programming track...it sounds more like a programming issue.

If "there's no issue with core-less motors" then I would like to know why three New motors failed Oxford N7 after barely two hours running from each of them.   One was the original and two replacements.   The fourth motor is different and has six holes in the drive-end and two larger holes in the opposite (electrical-connection) end, presumably for ventilation.   The latest motor has so far lasted 12hrs and cost £5.00.

The Oxford Dean goods started out with a 5 pole brushed motor with twin flywheels, the "revised" model with body errors corrected had a 3 pole cheapo coreless with one flywheel.

I have two, one failed after little use and Oxford sent a new motor free for me to fit myself, that has run OK since then, as has the second DG.

The original motor had gone short circuit which I found to be caused by fine metal particles loose inside one of which was across a commutator gap.

 

If you want a coreless 12v motor to fit an Oxford Rail loco you can buy one for under $1 on Ali Express

[Quadrille]

If Paying $1 for a motor, irrespective of where it may be from, then you will get what you pay for...

 

Miracles can sometimes be performed but the impossible takes a little longer! 

 

Go for better quality ventilated motors (£5.00-£7.00)  from, e.g., "bee_studio" on eB*y...

[Pete the Elaner]

Most of us have heard that Coreless motors do not like DC feedback controllers.

DCC motors are controlled by the decoder (which is why many often frown when the throttle is called the controller).

The decoder can be adjusted to provide a nice smooth voltage, or use feedback. The better decoders have better adjustment for this.

 

It may not be your problem, but it is something worthy of consideration.

[Lemmy282]

This evening I have fitted a Nigel Lawson coreless motor and dropper resistor into a 2mm finescale 0-6-0 chassis. I added a hardwired Zimo MX617 decoder and home made 660uf stay alive and it runs smoothly and down to a VERY slow call. No adjustment of any CV''s.

[melmerby]

4 hours ago, Quadrille said:

If Paying $1 for a motor, irrespective of where it may be from, then you will get what you pay for...

IMHO exactly the quality of the coreless motor in a Dean Goods..............

 

Instead buy a High Level one, expensive but good with plenty of poke.

Edited February 28 by melmerby

[Quadrille]

On 26/02/2024 at 11:55, TWG said:

Nigel Cliffe's statement above that there are no problems in principle with coreless motors is correct.  Over the years I have bought a number of locos with such motors and have retrofitted others with high quality ones (Faulhaber and Maxon).  I have never had a failure.  It looks to me as if Oxford, probably to keep costs down, bought some cheap motors of dubious quality.  The fact that your latest motor is different could suggest that they have realised their error.  I hope that the new motor is satisfactory, but £5.00 for a coreless motor does not to my mind suggest a top quality item

A £5.00 motor was/is actually £7.00 but I purchased ten and got them cheaper.  Personally, I detest coreless motors and I don't like paying for a brand-name.   To-date the N7 has covered about fifteen hours.   What I would like to do is change the drive between the motor and crown-gear so that I can fit a decent 5-pole real motor!