Coreless Motors

[ScRSG]

Browsing various sites it seems that there are an ever increasing number selling coreless motors, which may be of use to us. These can, sometimes, be purchased quite cheaply (as little as two or three pounds). The main reason for this post is that a large number of these motors seem to be designed for 3-5 volts dc ( for drones and such like).

The question is, can anything be added in circuit, such as resistors to make them run under our normal 12v  controllers? Any advice would be appreciated!

 

 

[DCB]

Resistors should do it but coreless motors are not known for their reliability in model railway applications mainly because the motors they use are too small for the task.  I would expect the Drone motors  to be too high revving and not have sufficient torque for model railway use even if you could find and fit suitably low gearing.   The coreless ones I found  on eBay have 1mm shafts which are not great for fitting drive gears to.

Edited March 15, 2023 by DCB

[ScRSG]

Thanks for that, and tend to agree about high speed of these. High Level do do a 1mm shaft worm for their gearboxes, which may help. Any ideas on the value of resistors?? I quite enjoy experimenting with such things!

 

Just to add, as the shafts on these motors tend to be too short, you can buy brass tube with an internal dia. of 1mm and an external dia. of 2mm which can extend the shaft and fit more standard 2mm worms.

Edited March 15, 2023 by ScRSG
To add more info.

[RobinofLoxley]

It's a mission to wade through all the offerings but certainly 2mm shafts exist and lower revving versions too. It's hard to know what would be the right spec.

[Vecchio]

Motors for drones are rather brushless types. To run them you need a controller which creates a variable frequency 3-phase current. In any case one of the most efficient electric motors (up to 85% efficiency). But probably not for model trains.

[DCB]

On 15/03/2023 at 10:32, ScRSG said:

Thanks for that, and tend to agree about high speed of these. High Level do do a 1mm shaft worm for their gearboxes, which may help. Any ideas on the value of resistors?? I quite enjoy experimenting with such things!

 

Just to add, as the shafts on these motors tend to be too short, you can buy brass tube with an internal dia. of 1mm and an external dia. of 2mm which can extend the shaft and fit more standard 2mm worms.

I have found worm gears tend to wobble if  short shafts are sleeved to extend them, the cure is an outrigger bearing, or a drive shaft to a stand alone worm drive like the old Airfix 14XX loco.   Some of these can and Coreless motors don't have effective end thrust bearings so don't work well or at all with worm drives.   However I am wondering about using a twin shaft motor with a big flywheel as a tender mounted motor driving the loco through a drive shaft and via a magnetic coupling so the motor wont stall and burn out so easily if overloaded.....

[RAF96]

Cordless motors do not have much in the way of bemf so slow speed control especially can be iffy. Add to that lack of torque spoken to earlier and one wonders why any loco maker would choose them at all.

Edited March 17, 2023 by RAF96

[Andy Hayter]

2 hours ago, RAF96 said:

Cordless motors do not have much in the way of bemf so slow speed control especially can be iffy. Add to that lack of torque spoken to earlier and one wonders why any loco maker would choose them at all.

 

Only if you use a feedback controller.

DC modellers like me don't use feedback controllers for exactly that reason.

For DCC, I cannot comment but I would guess there is not so much to chose between the motor types.