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After the discussion elsewhere about MFX decoders and that ESU will be offering support for these in use with ECoS, I had been reading up on them.

One of the things it said on the ESU website was;

QUOTE Motor management
The LokPilot V3.0 mfx runs DC - and coreless motors directly, while all-current motors need a Hamo-magnet retrofit. The motor is driven by 40 kHz Pulse width frequency (PWM) for a super silent, safe run. Together with the 128 mfx speed steps and fourth generation back EMF, unprecedented performance is realized.

Whats the difference between a "coreless" and a "all current" motor? How do I know which is which?
 

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QUOTE (neil_s_wood @ 20 Oct 2008, 10:09) <{POST_SNAPBACK}>After the discussion elsewhere about MFX decoders and that ESU will be offering support for these in use with ECoS, I had been reading up on them. Whats the difference between a "coreless" and a "all current" motor? How do I know which is which

***Hello Neil

You don't ask easy questions do you
!!

You really don't need to even think about this whole thing anyway - MFX is nothing special in this area as all current quality decoders are pretty well fine with 2 wire DC coreless motors (all it needs is a high frequency or "silent drive".

Coreless do exist in some EU models but are not all that common: I sometimes use them in the locos I build but not often.

The usual description of a normal DC motor is an "iron core motor" - conversely a coreless motor has no mass of Iron as part of the armature structure hence the name coreless.

BTW In this case I suspect that the ESU "all current" description is yet another blurring of clarity through yet another poor ESU translation effort.

The following imperfect info will give you the general differences...

The structure of the motor types is totally different - there is as stated above no Iron core in a coreless motor and so its moving mass is much less allowing much faster motor accelerations and greatly improved smoothness (the whole of the armature is the windings - often strengthened with a layer or epoxy or simlar for rigidity). They will also often be brushless - those which do have brushes usually having much smaller brushes than a standard DC motor - and they are always of precious metal such as gold.

They are very very efficient and smooth but because of the lower physical mass of the armature structure (ie its made up of only the windings with no Iron pole pieces) they are not very strong torque wise and are also very sensitive to bearing pressures and can be poor at handling higher direct loads as there is no real strength in the moving parts of the motor.

Because there is a low armature mass, they cannot dissipate heat well either. However when the drive and the motor are properly matched they make a super smooth and very very efficient drive system - so heat will then not be an issue.

So... its not just a matter of changing one for the other - Unless the motor is designed for the job to be done then the whole of the drive train may need to be changed to prevent inwanted bbering forces that would destroy the coreless motor.

Example is Portescap - its gearbox uses all helical gears which are very efficient and tend to not load the motors thust bearings. As a esult, you cannot safely substitute traditional worm drives which are very inefficient (only about 30% of motor power in a worm drive gets to the wheels).

A bit of web searching will probably show some structural illustrations if its of interest.
 

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QUOTE (neil_s_wood @ 20 Oct 2008, 12:57) <{POST_SNAPBACK}>Thanks for that Richard,so I would be right installing one of these in a DC loco assuming I had an MFX controller?

Is the Trix C sinus soft drive a coreless motor?

Most coreless motors are designed for DC so yes - it'd be OK in a standard DCC loco or DC loco too (although no pulse power from the DC controller please!)

The marklin c-sinus motor is a form of coreless motor that is also brushless - actually its not a DC motor at all but a 3 phase AC derivative with similar construction - it has 12 poles with the magnets attached to the drive shaft and surrounded by fixed position coils. It is driven by a sinusoidal AC waveform... and needs several wires connected for the 3 phases + timing signals, so it is only usable with a decoder which offers the correct software that can generate the waveform and control it properly.

Actually it is this Marklin motor thats really to blame for the curse of the %^&* 21 pin MTC connector!!

Richard
 

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Discussion Starter · #6 ·
QUOTE (Richard Johnson @ 20 Oct 2008, 15:44) <{POST_SNAPBACK}>Most coreless motors are designed for DC so yes - it'd be OK in a standard DCC loco or DC loco too (although no pulse power from the DC controller please!)

The marklin c-sinus motor is a form of coreless motor that is also brushless - actually its not a DC motor at all but a 3 phase AC derivative with similar construction - it has 12 poles with the magnets attached to the drive shaft and surrounded by fixed position coils. It is driven by a sinusoidal AC waveform... and needs several wires connected for the 3 phases + timing signals, so it is only usable with a decoder which offers the correct software that can generate the waveform and control it properly.

Actually it is this Marklin motor thats really to blame for the curse of the %^&* 21 pin MTC connector!!

Richard
Aha it all makes sense now. Thanks again Richard.
 

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Not that I have any locomotives equipped with the new motor, but a few friends have them.

It is very quiet and very powerfull. Low end spead is fantastic although the top end speed is to quick for my liking, but then I only run slow trains!
 

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QUOTE (zmil @ 20 Oct 2008, 02:39) <{POST_SNAPBACK}>Hi Neil

I'm not 100% sure , but I think the All Current is the Marklin AC motors (which require a magnet added for conventional operation with the ESU decoder

Regards Zmil

Zmil may not be 100% sure but he is 100% correct. All Current is a direct translation from the German Allstrommotor . Maerklin also used something called a Feldspulenmotor, which literally means field windings motor - I think that this is a different motor but they may be the same.

I do not understand why they are called all current motors, since they will not work on DC in the absence of a magnet. Hence the reference to retrofitting Hamo magnets. At one time Maerklin sold 2 rail versions of their locos under the Hamo name. Hamo was a small firm, which, before it was taken over by Maerklin, specialised in the 1960s in trams. They also produced a model of the prototype version of the German V160 loco. This had what was at the time probably the best motor of any model on the market. I had one and it ran beautifully, better than any of my other locos from big manufacturers.

Coreless motors are called in German Glockenankermotoren, literally bell armature motors. They are also often referred to as Faulhaber motors, after Dr Faulhaber who invented them. His firm is probably the largest producer (see www.faulhaber.de)
 

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Discussion Starter · #9 ·
QUOTE (john woodall @ 21 Oct 2008, 18:20) <{POST_SNAPBACK}>Not that I have any locomotives equipped with the new motor, but a few friends have them.

It is very quiet and very powerfull. Low end spead is fantastic although the top end speed is to quick for my liking, but then I only run slow trains!
I have one in my BR05 003 and it is impressive.

I am sure that many Trix loco's have bell armature motors according to their catalogue.
 

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QUOTE (TWG @ 21 Oct 2008, 11:12) <{POST_SNAPBACK}>Zmil may not be 100% sure but he is 100% correct. All Current is a direct translation from the German Allstrommotor . Maerklin also used something called a Feldspulenmotor, which literally means field windings motor - I think that this is a different motor but they may be the same.

I do not understand why they are called all current motors, since they will not work on DC in the absence of a magnet.

Maerklin's so called Allstrommotor is indeed a Feldspulenmotor or wound field motor as opposed to a permanent magnet motor.

Maerklin call them "Allstrom" for the very reason that they will run on DC and AC whereas permanent magnet motors will only run on DC. The conversion to permanent magnet is usually done when fitting a decoder with motor regulation since wound field motors do not generate back emf needed for regulation
 
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