Does the Hornby K1 have a coreless motor?

[Sandpiper]

Not sure where to put this so I'll try in here.

 

I can't find a definitive answer to this question online. A search shows up a few results suggesting that it might but nothing definitive. 

 

The reason I ask is that I have two Hornby K1s and they really do not like my Gaugemaster HH feedback controller. They run very smoothly at ultra slow speed, ie walking pace, but are very jerky at anything faster. However they do run smoothly at faster speeds using a Gaugemaster Combi non feedback controller.

 

Clearly they are capable of running smoothly at all speeds but it seems I can have smooth slow speed or smooth faster speed (15-20 mph +) but not both using one controller.

 

Do they dislike the HH because it is a feedback controller and they have coreless motors? Is it possible to tell just by looking at the motor? They are fully sealed motors and the innards cannot be seen. 

 

None of my other locos have a problem with the feedback controller.

Edited August 19, 2018 by Sandpiper

[Horsetan]

I'm not aware of Hornby ever using coreless motors. I recall DJM/DJM-related engines having them specified, but no other British outline manufacturer seems to use them.

[Broadway Clive]

Years ago I had jerky running with a Bachmann K3 and Flying pig Ivatt controlled by a Gaugemaster HH that was cured by snipping off the DCC boards and rewiring. Later Bachmann produced blanking plugs to overcome the problem and I suspect Hornby use them too now, so I suggest you check that it is fitted tightly as I have known one to become lose.

[jimwal]

Feedback controllers appeared many years ago to give improved slow running control of the fairly basic motors of the time. Coreless motors with a gearbox for model railway locos arrived, for which the feedback controllers were incompatible with.

 

Virtually all recent locos have 'can' motors of various types, these are generally better than the old motors, but cheaper and more durable than coreless types. Can motors are normally better without feedback control, I believe it can shorten brushgear life in some cases.

 

So coreless or can types, no feedback!

 

Jim

[34theletterbetweenB&D]

Virtually all DCC decoders now have feedback, and since a high proportion will be partnered with current can motored productions and there is no storm of protest, I don't believe there is any intrinsic feedback + can motor problem. Of my seventy DCC controlled can motored locos (Lenz/Zimo/ESU decoders all with feedback) which run near daily I have had zero motor failures over the fifteen years since my first beginnings with DCC.

 

Now, one of the earlier decoder designs, an ESU lokpilot v1.0 badged as Bachmann, could induce jerkiness on what had been smooth running can motored mechanisms as originally tested on a DC resistance controller. Adjustment of the sampling and feedback constants fixed that. Possibly some feedback controllers designed with high current consumption open frame motors may similarly not do so well when presented with a more efficient can motor?

 

After all that, forgot to add that the K1 motor appears to be a regular iron core type, although I wouldn't mind if it proved to be coreless, it's been trouble free so far on the two mechanisms I have running (one repurposed for another class).

Edited August 20, 2018 by 34theletterbetweenB&D

[jimwal]

Agree entirely, the ability to adjust settings in DCC decoders gives scope to match virtually any motor type. I don't know if analogue controllers with feedback are able to do this.

[Sandpiper]

Thanks for the replies. Nothing I do makes any difference to these two locos. They both misbehave using the feedback controller in exactly the same way as each other. All my other locos are fine with this controller.

 

They are capable of running smoothly at any speed, just not using the same controller, so it is not a case of them simply being poor runners. Feedback is fine at walking pace but jerky at faster speeds; non feedback is fine at faster speeds but they won't really run at all at walking pace. I was considering trying DCC as I would like consistently smooth running at all speeds using one controller. Maybe it is time to take the DCC plunge.

[Theakerr]

As a general comment I would disagree about most new models having can motors.  I have been surprised at how many of my newer models (J11, Butler Henderson and Claude) have old open frame motors.  At least one, the J11 appears to be only a three pole.

[jimwal]

Sandpiper,

Are your K1s new or unused? If so it may help to give them a period of running-in in each direction at a moderate speed. Hornby don't mention this in their instructions unlike most other manufacturers but I have found it can sometimes help. Also check lubricant has not dried out.

 

As regards model motors the terms 'can' and 'open frame' need a bit more explanation.

 

Open frame types are usually considered as the Triang/Hornby X04 and the similar MW 05 and Romford Phantom among others. These all have a block magnet at one end, a pair of pole pieces and brushgear at the opposite end forming the open frame.

 

The can motors have a pair of small magnets, one above the armature and one below. These, with the bearings are held together in a pressed steel 'can' sealed with a plastic end that holds and insulates the brushgear.

 

Most of the Bachmann steam locomotive motors have a hole each side and indeed are 3 pole but seem to run as smoothly as 5 pole motors. Some small motors have the same layout but only a steel strip around the outside so appear to be 'open frame' but are nothing like the old X04 types.

 

Hope this helps.

 

Jim.

[34theletterbetweenB&D]

... I was considering trying DCC as I would like consistently smooth running at all speeds using one controller. Maybe it is time to take the DCC plunge.

 One of the great assets of DCC is the individual 'tuning' that it makes possible. This is invaluable with RTR models where you are stuck with the manufacturer's design choices.  Provided the mechanism is competent, the different performance schemes the various manufacturers favour (and have favoured in the past) can all be moved into alignment. So of current model productions Hornby's tendency for anything up to 200mph maxima on express locos may be tamed, while the less than full scale speed capability found at 12V on some Bachmann and Heljan models may be dealt with by increasing the track supply voltage. (For the latter capability, a full system is required, many basic systems do not offer this.) The occasional wayward motor response characteristic is also easily dealt with if the decoder offers programmable speed curves.

 

You do need to think the quality end of the DCC market to obtain all this. Having sampled widely by the agency of friend's decoder choices which I then fit into their locos; I am fully convinced of the merits of DCC products from two makers: Lenz' standard decoder for most current well tempered mechanisms is the easy VFM choice, a little more cash for Zimo when some heavyweight adjustment is required to cudgel the best possible performance out of a reluctant mechanism. 

As a general comment I would disagree about most new models having can motors.  I have been surprised at how many of my newer models (J11, Butler Henderson and Claude) have old open frame motors.  At least one, the J11 appears to be only a three pole.

 Other than some early Blue Riband productions with Buhler and Mashima motors, all of Bachmann's steamers have three pole can motors of in-house design. some have openings in the can 'flats', other's don't, and I can detect no rhyme or reason for this! But can motors they are in design per Jim's post above, and very efficient too. With good feedback control they perform indistinguishably on track from five pole types in the same mechanism - I can make the direct comparison on Bach's WD (Buhler) and A1 (Mashima).

 

Hornby aren't saying AKAIK what is inside the slim can motors in many recent productions. Since they were always very forward in mentioning that their black can motor  was a five pole unit, I suspect three pole.

 

Likewise Heljan have adopted a slim cylindrical three pole can motor for some of their more recent productions. All their earlier 'full body width' diesels and electrics uniformly have a Buhler five pole unit of similar dimensions to Hornby's 'black can' type and Bachmann's 881 motor found in their centre motor D+E models.

[Sandpiper]

Thanks for the further replies.

 

Both K1s have been very well run in and appropriately lubricated. Maybe it is just coincidence that I have two poor runners dogged by the same issue, whatever it may be. It just seems a bit odd that they will both run smoothly at walking pace with a feedback controller, or smoothly at faster speeds with a non feedback controller, but not both. They are the only two locos I have a problem with. I have a variety of different locos bought for various aborted projects, from a Hornby Black 5 to a Dapol Western, and they all run beautifully smoothly on the feedback controller at any speed.

 

 

 

 

 

[Theakerr]

By Jim's definition of a can motor, I stand corrected.  However, I feel it is more correctly an upgraded open frame.  To me a can motor is one that is completely sealed literally inside a can and has the benefit that the can excludes all dust etc.

[Sandpiper]

Well, I managed to get one of the K1s running much more smoothly. One of the bearings for the centre drivers wasn't seated correctly. I hadn't noticed it last time I took the chassis apart.

 

Also, just to make the day more "interesting" I decided to jump into the DCC waters as well. Unfortunately the DCC manual turned out to be written in some strange incomprehensible language which didn't help to make my day overly relaxing. Eventually I worked out how to tweak motor settings and got the other K1 running smoother as well, although not quite as good as the one that had the incorrectly seated bearing. 

 

Then I discovered another problem. Both K1s caused a short on the curved route through my Peco bullhead points. It turned out the pony truck wheels back to back was out so was simple to fix, but interesting that it hadn't been a problem with the DC feedback controller. Lots of useful stuff learnt anyway. Thanks again.

Edited August 22, 2018 by Sandpiper

[Izzy]

Virtually all DCC decoders now have feedback, and since a high proportion will be partnered with current can motored productions and there is no storm of protest, I don't believe there is any intrinsic feedback + can motor problem. Of my seventy DCC controlled can motored locos (Lenz/Zimo/ESU decoders all with feedback) which run near daily I have had zero motor failures over the fifteen years since my first beginnings with DCC.

 

Now, one of the earlier decoder designs, an ESU lokpilot v1.0 badged as Bachmann, could induce jerkiness on what had been smooth running can motored mechanisms as originally tested on a DC resistance controller. Adjustment of the sampling and feedback constants fixed that. Possibly some feedback controllers designed with high current consumption open frame motors may similarly not do so well when presented with a more efficient can motor?

 

After all that, forgot to add that the K1 motor appears to be a regular iron core type, although I wouldn't mind if it proved to be coreless, it's been trouble free so far on the two mechanisms I have running (one repurposed for another class).

The difference between DC feedback controllers and DCC decoders BEMF as I understand it is is that the former use quite low frequency, while the latter (although early ones didn’t), use higher frequency which doesn’t impact coreless/high efficiency motors in the way that low frequency does. Many decoders such as Zimo’s also have a choice of frequency levels/coreless settings - usually either 16khz or 32khz (Zimo is 20khz or 40khz ) - to assist with this aspect.

 

Using DC feedback controllers with the better/more efficient motors, can or coreless, is still something to be avoided in general whenever possible in my experience.

 

Izzy

Edited August 23, 2018 by Izzy

[melmerby]

There is a topic on coreless motors and they are more common than you think:

 

http://www.rmweb.co.uk/community/index.php?/topic/129067-coreless-motors-what-rtr-has-them/

 

Keith

[NIK]

The difference between DC feedback controllers and DCC decoders BEMF as I understand it is is that the former use quite low frequency, while the latter (although early ones didn’t), use higher frequency which doesn’t impact coreless/high efficiency motors in the way that low frequency does. Many decoders such as Zimo’s also have a choice of frequency levels/coreless settings - usually either 16mhz or 32mhz - to assist with this aspect.

 

Using DC feedback controllers with the better/more efficient motors, can or coreless, is still something to be avoided in general whenever possible in my experience.

 

Izzy

 

Hi Izzy,

 

 

I think you were thinking of kilohertz not megahertz. I also think some early designs of DCC decoders may have used lower frequencies since later decoders were often advertised as having new high frequency (~19khz) options.

 

Regards

 

Nick

[Izzy]

Hi Izzy,

 

 

I think you were thinking of kilohertz not megahertz. I also think some early designs of DCC decoders may have used lower frequencies since later decoders were often advertised as having new high frequency (~19khz) options.

 

Regards

 

Nick

 

Yes, many thanks for the heads-up, and sorry for the error. I've now corrected it and added the Zimo specs on this so there is no confusion for anyone.

 

regards,

 

Izzy

[34theletterbetweenB&D]

...Then I discovered another problem. Both K1s caused a short on the curved route through my Peco bullhead points. It turned out the pony truck wheels back to back was out so was simple to fix, but interesting that it hadn't been a problem with the DC feedback controller...

A big difference between DC and DCC. DC is tolerant of momentary short circuits, while DCC is not, the necessary short circuit protection provision kicking in very quickly to prevent continuing high current at the short circuit location.

 

I find this is a problem with some RTR model construction schemes. Hornby persisted with chassis block live to one rail for some time after the move to China, and this proved something of a hostage to fortune, as it leads to a vulnerability to momentary short circuits. Bachmann have for some time - and now Hornby do too - had cast metal footplates on steam models. If the track has gradient transitions enough that a carrying wheels flanges contact the footplate underside, once the paint is worn through, there's the potential for a momentary short.

 

Once you know these things it's easy enough to sort out, but it's a puzzle at first...

[melmerby]

Hi Izzy,

 

 

I think you were thinking of kilohertz not megahertz. I also think some early designs of DCC decoders may have used lower frequencies since later decoders were often advertised as having new high frequency (~19khz) options.

 

Regards

 

Nick

 

Yes, many thanks for the heads-up, and sorry for the error. I've now corrected it and added the Zimo specs on this so there is no confusion for anyone.

 

regards,

 

Izzy

Being pedantic it was milli not Mega!

 

Keith

Edited August 23, 2018 by melmerby