Coreless Motor...

[Heiter]

Hi All...

 

Anybody had/having issues with their N7 suddenly stopping due to motor issue(s)..?    I had to return my 1st/last.    Removing the body and turning the flywheel revived it for a while but it was intermittent so it went back, obviously!    Two emails to "Oxford Rail" within the past month or tw didn't produce a diddly squat!!   No excuse for ignorance.

This is the 2nd model purchased new that's suffered with coreless motor issues (2nd was DJM 14xx broken wire within the motor-cap) and they aren't cheap motors in comparison to something like a 6-pole 15mm x 15mm which are brilliant for about £2.00 each or less.

Cheers...

[hayfield]

Heiter

 

I have been using a RG4 for quite some time without issue and have one of the High Level coreless which also works extremely well

 

I had a much cheaper 8mm which is a replacement motor for a Roco 009, it would only go one way after a short period, seller replaced it but not fitted it yet

 

I bought from another Dutch seller 3 £10 coreless motors, the 12mm can ran well for a period then stopper

 

All these 4 are used/tested with an old H&M Safety Minor at 12 volts 1.5 amps. All of these motors are supposed to be low revving designed/suitable for model railway, Both the Dutch examples seem far more fragile than the more expensive types and I am suspicious not rated for 12 volts, certainly I have found they are not as robust as the more expensive. I could be wrong and just unfortunate having both I have used fail, or they do not like older transformers ?  

[Heiter]

Thank you John...   I think I'll avoid models with coreless motors until they become more reliable!

 

Cheers...

[hayfield]

36 minutes ago, Heiter said:

Thank you John...   I think I'll avoid models with coreless motors until they become more reliable!

 

Cheers...

 

Heiter

 

That is not quite what I was trying to say, steer clear from cheap £10-£15) coreless motors. Chris at High Level does 2 motors a 1619 and a 1620 £27.50 & £29 respectively each. These are far superior than the equivalent sized Mashima's and at todays prices cheaper. Absolutely stunning motors, well worth the cost

 

 

A High Level 1619 coreless in a Southeastern Finecast SR E1 chassis

 

 

From memory the gearbox is a High Level Roadrunner

[Heiter]

My experience of coreless motors has left me a "Doubting Thomas", I'm afraid.

 

Cheers...

:-)

[chris p bacon]

33 minutes ago, Heiter said:

My experience of coreless motors has left me a "Doubting Thomas", I'm afraid.

 

Cheers...

:-)

 

What are you using to control them ?

 

The problem may not be with the motor as I have not encountered any problems with coreless.

[Jeff Smith]

Can the High Level motors have extended shafts for flywheels?I

 

I heard that coreless motors are best with pure dc controllers and can have problems with feedback type controllers.  I assume dcc chips put out pure dc to the motor but not sure.

[009 micro modeller]

If they are rated at less than 12V and are being used with a 12V feedback controller (which coreless motors don’t work well with, although I’m not absolutely sure of the specific technical reason for this), then the issue is with the controller rather than the motor.

[Izzy]

Yes, on DC the low frequency of PWM (feedback) controllers doesn’t best suit coreless motors. DCC decoders put out higher frequency PWM. Many better ones also have choices with these levels and other adjustments (cv’s) that can fine tune the decoder BEMF output - feedback level, sampling rate etc - to suit each individual motor, and can of course be done for any motor type quite besides those of speed levels and rates of acceleration/deceleration and so forth.

 

Izzy

[hayfield]

2 hours ago, Heiter said:

My experience of coreless motors has left me a "Doubting Thomas", I'm afraid.

 

Cheers...

:-)

 

I have not had any issues with decent coreless motors, however at the cheaper end £18 or less) I have had issues. My own thoughts are the cheaper ones may not actually be 12 volt rated and or very low amperage.

 

Conclusion buy quality items, eg High Level, they are cheaper than many Mashimas now on sale

[flubrush]

I do remember from investigating coreless motors many years ago that the recommended constant running current was quite a bit lower than the maximum recommended current for a motor.  So if you run a locomotive with a heavy load such that the currnet is close to its maximum then the life of the motor will be adversly affected.   One simple way of avoiding this was to adjust the weight of the locomotive such that the preferred lower current was attained when it slipped.   This was over and above powering it with a controller which suited a coreless motor,  as noted above in the thread.

 

Jim.

[bigherb]

Are we sure it is fitted with a coreless motor? Or is just forum myth.

[Flying Pig]

4 hours ago, bigherb said:

Are we sure it is fitted with a coreless motor? Or is just forum myth.

 

Wise Sir Bigherb - How do you know it is a coreless motor?

 

RMweb - It looks like one! Burn it! It turned me into a Dean goods! etc

 

Wise Sir Bigherb - There are ways of telling whether it is a coreless motor.  Tell me - where are Portescaps made?

 

...

 

Small Smelly Person - So if it weighs the same as a Toblerone, ...it's from Switzerland...

 

Wise Sir Bigherb - And therefore?

 

RMweb - A coreless motor!!

 

[cctransuk]

15 hours ago, flubrush said:

I do remember from investigating coreless motors many years ago that the recommended constant running current was quite a bit lower than the maximum recommended current for a motor.  So if you run a locomotive with a heavy load such that the currnet is close to its maximum then the life of the motor will be adversly affected.   One simple way of avoiding this was to adjust the weight of the locomotive such that the preferred lower current was attained when it slipped.   This was over and above powering it with a controller which suited a coreless motor,  as noted above in the thread.

 

Jim.

 

Would not adjusting the weight of the locomotive - presumably downwards - affect its ability to haul trains?

 

Surely the sensible course is to select a motor that can accept the current load, resultant from the weight of the loco necessary to achieve the desired ability to haul trains?

 

I certainly wouldn't wish to allow the motor in my loco to limit its haulage capacity, within my reasonable prototypical expectations.

 

John Isherwood.

[hayfield]

I have seen and have myself a RG4 in a will pannier tank. I also have one of High Level's coreless motors in a Southeastern Finecast again works without an issue

 

I bought a £11 coreless motor from a European company, worked fine to start with, performance dropped off then stopped completely. I had a second coreless motor for an 009 loco, after a while would only work one way ( the seller changed the motor, but not used it yet

 

I think when you look and feel a motor, it shows its quality. Certainly High Levels when put alongside cheaper motors looks better quality and works very well. Have a chat with Chris he might be in a better position to explain matters better

[flubrush]

4 hours ago, cctransuk said:

 

Would not adjusting the weight of the locomotive - presumably downwards - affect its ability to haul trains?

 

Surely the sensible course is to select a motor that can accept the current load, resultant from the weight of the loco necessary to achieve the desired ability to haul trains?

 

I certainly wouldn't wish to allow the motor in my loco to limit its haulage capacity, within my reasonable prototypical expectations.

 

Certainly lightening a locomotive to bring its slip current down to the required value would reduce its hauling capacity and if you required more tractive effort then a coreless motor with a higher current capability would be an obvious choice.  But some years ago,  when coreless motors like the Portescap products appeared on the scene,  modellers didn't have a ready range of coreless motors to choose from.   If you wanted the benefits of using a coreless motor and had got an RG4 and you didn't want to burn it out,  then you got a suitable controller and limited its running current.   It might not have pulled as much as you wanted it to and then you might have had to look for another type of power unit.

 

Another advantage of setting the slipping current of a locomotive is that if it is powered,  but prevented from moving,  then the maximum current drawn will be limited by the slipping.    I've often seen a loco grinding away at the end of a siding when the operator hasn't noticed that it is still powered - been there done that. :-)    If the loco had been weighted to increase pulling capacity and could no longer slip,  then the motor could be damaged.

 

Jim.

[cctransuk]

1 hour ago, flubrush said:

 

Certainly lightening a locomotive to bring its slip current down to the required value would reduce its hauling capacity and if you required more tractive effort then a coreless motor with a higher current capability would be an obvious choice.  But some years ago,  when coreless motors like the Portescap products appeared on the scene,  modellers didn't have a ready range of coreless motors to choose from.   If you wanted the benefits of using a coreless motor and had got an RG4 and you didn't want to burn it out,  then you got a suitable controller and limited its running current.   It might not have pulled as much as you wanted it to and then you might have had to look for another type of power unit.

 

Another advantage of setting the slipping current of a locomotive is that if it is powered,  but prevented from moving,  then the maximum current drawn will be limited by the slipping.    I've often seen a loco grinding away at the end of a siding when the operator hasn't noticed that it is still powered - been there done that. :-)    If the loco had been weighted to increase pulling capacity and could no longer slip,  then the motor could be damaged.

 

Jim.

 

All true - but still an ill-judged choice of motor; if the motor won't produce the required output safely - wrong motor. It may have been a problem years ago - but not now.

 

....and - "the benefits of using a coreless motor" - please explain.

 

Regards,

John Isherwood.

[NIK]

2 hours ago, flubrush said:

 

Certainly lightening a locomotive to bring its slip current down to the required value would reduce its hauling capacity and if you required more tractive effort then a coreless motor with a higher current capability would be an obvious choice.  But some years ago,  when coreless motors like the Portescap products appeared on the scene,  modellers didn't have a ready range of coreless motors to choose from.   If you wanted the benefits of using a coreless motor and had got an RG4 and you didn't want to burn it out,  then you got a suitable controller and limited its running current.   It might not have pulled as much as you wanted it to and then you might have had to look for another type of power unit.

 

Another advantage of setting the slipping current of a locomotive is that if it is powered,  but prevented from moving,  then the maximum current drawn will be limited by the slipping.    I've often seen a loco grinding away at the end of a siding when the operator hasn't noticed that it is still powered - been there done that. :-)    If the loco had been weighted to increase pulling capacity and could no longer slip,  then the motor could be damaged.

 

Jim.

Hi,

 

I don't know of any controllers that limit the current in order to work with coreless motors.

Peak current can be limited with coreless motors by using PWM with a high enough repetition rate to counteract the lower inductance of coreless motors.

Coreless motors tend to be more efficient than iron cored motors so any lack of torque may be due to selection of a lower torque motor. In recent years most controllers have enough current to cope with most locos including some mainline OO locos by Heljan with current draw up to about 1 amps.

 

Regards

 

Nick

 

 

[flubrush]

3 hours ago, cctransuk said:

 

All true - but still an ill-judged choice of motor; if the motor won't produce the required output safely - wrong motor. It may have been a problem years ago - but not now.

 

....and - "the benefits of using a coreless motor" - please explain.

 

 

Putting a coreless motor,  like an RG4,  in a locomotive was certainly not ill-judged.   The higher, low speed torque of the coreless motor coupled with the high efficiency gearbox gave really excellent excellent speed control from zero.    If your interest was belting a loco and 12 up round a circuit at high speed,  then an RG4 could have been an ill-judged choice.

 

Jim.

[NCB]

A lot of current N scale locomotives use coreless motors. I believe Pendon locomotives mainly use coreless motors, and they have a fairly demanding schedule. There's nothing wrong with using coreless motors.

 

Just don't use them with DC feedback controllers. DCC so-called "silent" decoders with or without feedback are fine because they use high frequency.

 

I've started to use coreless motors in my 3mm/ft models due to the demise of Mashima, and also at the moment I'm building some rather small examples with limited room inside. I like them, very smooth, and so far no problems. To be fair they don't get that demanding use. But the way I'm using them if one packs up it's easily replaced. So far I use 7x16mm models from a batch of 16 I bought from the far east for £25, and 8x16.9 models from Tramfabriek, I believe quite a few 2mm/ft modellers are using these.

 

Nigel

[NIK]

1 hour ago, NCB said:

A lot of current N scale locomotives use coreless motors. I believe Pendon locomotives mainly use coreless motors, and they have a fairly demanding schedule. There's nothing wrong with using coreless motors.

 

Just don't use them with DC feedback controllers. DCC so-called "silent" decoders with or without feedback are fine because they use high frequency.

 

I've started to use coreless motors in my 3mm/ft models due to the demise of Mashima, and also at the moment I'm building some rather small examples with limited room inside. I like them, very smooth, and so far no problems. To be fair they don't get that demanding use. But the way I'm using them if one packs up it's easily replaced. So far I use 7x16mm models from a batch of 16 I bought from the far east for £25, and 8x16.9 models from Tramfabriek, I believe quite a few 2mm/ft modellers are using these.

 

Nigel

Hi,

 

DC feedback controllers are fine for coreless motors providing they use a high enough repetition rate (high frequency).

 

Regards

 

Nick

[Nile]

Is there such a beast? (a high frequency DC feedback controller that isn't a DCC decoder).

[bigherb]

11 hours ago, cctransuk said:

 

 

 

....and - "the benefits of using a coreless motor" - please explain.

 

Regards,

John Isherwood.

Low power consumption, good if you are using batteries, not really relevant for model railways with mostly powered by mains transformers.

Low inertial, great for drones etc where you want quick response from the motor. Locomotives need the opposite high inertia to stop jerking, why flywheels are fitted to increase inertia.

Small size might handy for N gauge. But Hornby have produced some excellent running dimunitive Locomotives Peckett, Rushton, Sentinal, Rocket with conventional motors.

So for model locomotives not really any benefit.

[NIK]

1 hour ago, Nile said:

Is there such a beast? (a high frequency DC feedback controller that isn't a DCC decoder).

Hi,

 

I understand most PWM/feedback controllers designed since about 1980 use high frequency (see other topics on this on RMWeb).

 

Coreless motors were very expensive when they became more common in kit and scratch built steam locos in the 1970's so I guess there was pressure on DC controller manufacturers to produce PWM controllers that could not burn out coreless motors due to the wrong frequency.

 

I don't think its easy to check if a DC PWM controller is high frequency or not.

 

I've just checked if the Bachmann Class 117 DMU uses coreless motors because of my worry about it being run with too low a frequency drive. Judging by its motors DC resistance and inductance at 1khz it does not have coreless motors.

 

Regards

 

Nick

[hayfield]

For years coreless motors have been seen to be the gold standard for locos, especially where slow smooth operation is required, why now are they being questioned

 

No one would question me for using a Mashima motor, but they are now only available at about £35 or more

 

High Level kits have 2 coreless motors both for under £30, and a performance far better than Mashimas

 

Hands up standard motors have improved over the years and can motors if designed/ compatible for model railways do now perform well

 

BUT many of the cheap ones available on the internet are far from desirable, I have found them to be much to high revving, many possible are seconds etc. I have one of High Levels iron frame motors, its tiny so ideal for small locos and works well, plus a third of the price Mashima's are changing hands for

 

Given the choice between a High Level coreless motor and a Mashima, its High Level all the time

 

As for can motors, if they are both low revving and fit standard gearboxes and of course work well , it may be an alternative