96RAF Posted July 3 Share Posted July 3 N20 is just a generic class of motors. There can be great variation twixt voltage range, manufacturers , etc. I have some long shaft geared ones and they are superb quality. Link to comment Share on other sites More sharing options...
Rallymatt Posted July 3 Share Posted July 3 N20 merely describes the dimensions of the motor can, nothing else. Link to comment Share on other sites More sharing options...
DJBDoug Posted July 6 Author Share Posted July 6 The AliExpress motors arrived: The AliExpress and Hornby have the same winding impedance. They look Similar for fit but not identical in details. The end cap and brushes are a direct fit into Hornby case and motor so you could just swap that to get new brushes on the Hornby motor. I will replace the motor and do an AliExpress vs Hornby crawl and speed test side by side. Im sure as a kid (40 years ago - the last time I pulled a motor apart) I pulled magnets out of motors and put a sheet of plastic behind the magnets to get the closer to the coils to make more power? torque? or more sensitive? I might try that when I get time. 1 Link to comment Share on other sites More sharing options...
Rallymatt Posted July 6 Share Posted July 6 Replacing the ‘brushes’ is a serious consideration for anyone who doesn’t have a worm gear puller etc. I am still waiting for the EBay motors. My stock of Micro Motor coreless arrived 12 hours after ordering. Options 😁 Link to comment Share on other sites More sharing options...
DJBDoug Posted July 7 Author Share Posted July 7 (edited) So I modified an AliExpress motor. Removed the magnets and spaced them closer to the coils. stock distance between magnets: and diameter of coils: added a sheet of plastic behind each magnet: reduced gaps to coils: Tested 3 OE vs the AliExpress motor and the modified AliExpress motor. 9f677d26-6e10-4f7f-9fae-af370e232e6a.mp4 498eab19-b6f4-480e-914a-611cc40dcc95.mov There is a slight difference between the OE motors. The AliExpress motor has a different noise and is faster than OE and starts/stops turning at a lower voltage. The modified motor is faster again and operates down to a lower voltage than OE and similar to standard AliExpress motor. 9f677d26-6e10-4f7f-9fae-af370e232e6a.mp4 498eab19-b6f4-480e-914a-611cc40dcc95.mov Edited July 7 by DJBDoug 3 Link to comment Share on other sites More sharing options...
GMD Posted July 8 Share Posted July 8 Very interesting experiment. And impressive finesse to make these mods! Link to comment Share on other sites More sharing options...
DJBDoug Posted July 26 Author Share Posted July 26 Some more updates 2 genuine Hornby motors but one has the carbon brushes fitted. running both in reverse, at a a high power, and will leave running the next couple of days, to see how long they last. Or at least see how much wear on the carbon brushes over 30-40 hours of use IMG_8011.mov 5 Link to comment Share on other sites More sharing options...
Rallymatt Posted July 26 Share Posted July 26 (edited) Great, some more tests 👍 I’m really interested to know if they have any difference in performance/noise. Hopefully the service life is superior to the OE ones. I’m planning on some load tests and recording temps on motors to see if there is any truth in this being an issue. Edited July 26 by Rallymatt Link to comment Share on other sites More sharing options...
What About The Bee Posted July 27 Share Posted July 27 (edited) On 06/07/2024 at 12:10, DJBDoug said: Im sure as a kid (40 years ago - the last time I pulled a motor apart) I pulled magnets out of motors and put a sheet of plastic behind the magnets to get the closer to the coils to make more power? torque? or more sensitive? I might try that when I get time. Inverse square law. Magnetic attraction decreases as the distance increases by the square . Conversely, magnetic attraction increases when the distance is reduced, by the square of the reduction in distance. Moving the magnets closer to the coil makes for a much more powerful motor, given the same voltage and amperage. It will generate more torque as compared to an unmodified motor. Therefore, your locomotive will start moving at a lower voltage than the same locomotive with an unmodified motor. The downsides? Controlling the gap becomes more and more critical. Loose fitting bearing surfaces can lead to the lamination and coils touching the magnets. If ignored, this can cause magnet and or coil failure. Higher magnetic forces lead to premature bearing wear, providing the loose fitting bearing surfaces. Bee Edited July 27 by What About The Bee Link to comment Share on other sites More sharing options...
DJBDoug Posted July 27 Author Share Posted July 27 1 hour ago, What About The Bee said: It will generate more torque as compared to an unmodified motor. Therefore, your locomotive will start moving at a lower voltage than the same locomotive with an unmodified motor. Bee That is what I saw in practise . I tried 2 sheets of plastic behind magnets and they stayed to touch/scuff. Link to comment Share on other sites More sharing options...
dBerriff Posted July 27 Share Posted July 27 To be pedantic, and I apologise for this, the power of a motor is not increased by a stronger magnetic field. What is increased is the torque (force) for a given current. The back EMF is also increased so full torque is developed at a lower RPM. Hence the counter-intuitive discovery that open-frame motors run slower if updated with neodymium magnets. Full-size electric locos used to reduce the field currents to run faster. 1 Link to comment Share on other sites More sharing options...
Rallymatt Posted July 27 Share Posted July 27 I don’t think we are going run out of ideas for keeping our locos running, there is plenty of enthusiasm and brain power available 😁👍 Link to comment Share on other sites More sharing options...
DJBDoug Posted July 28 Author Share Posted July 28 At 24 hours both still going but in the morning at 35 hours, both had stopped working with the hornby controller dead. I get an output from the constant output on back but the controller voltage is dead. I used the hornby controller as I read it had overcurrent protection. the oe hornby class 08 is shorting, and the carbon brushed 08 still works. you can see one of the metal brushes has failed, and the other is very burned. and the carbon brushes still look as new so a 24-35 hour life span as predicted by @Rallymatt Im not going to run the brushed motor to destruction as I’m going on holiday and I expect it will run for days. 1 6 Link to comment Share on other sites More sharing options...
Silver Fox 17 Posted July 28 Share Posted July 28 (edited) 36 minutes ago, DJBDoug said: At 24 hours both still going but in the morning at 35 hours, both had stopped working with the hornby controller dead. I get an output from the constant output on back but the controller voltage is dead. I used the hornby controller as I read it had overcurrent protection. the oe hornby class 08 is shorting, and the carbon brushed 08 still works. you can see one of the metal brushes has failed, and the other is very burned. and the carbon brushes still look as new so a 24-35 hour life span as predicted by @Rallymatt Im not going to run the brushed motor to destruction as I’m going on holiday and I expect it will run for days. Thanks, you have proved what we were under the impression of regarding the wipers. At least we have a solution. I imagine the brushed one will last years never mind days. Well done Edited July 28 by Silver Fox 17 1 Link to comment Share on other sites More sharing options...
Rallymatt Posted July 28 Share Posted July 28 Great work, I’ll fit some carbon Brushes when they arrive and do some real world testing and measure how hot they get hauling trains and reversing etc. Did you notice any difference in performance of noise etc as sometimes suggested with carbon brushes? Link to comment Share on other sites More sharing options...
Andrew-372848 Posted July 28 Share Posted July 28 This is quite a revelation and while not all of us will run our locos continuously looks to be a severe limitation on the serviceability of these motors and consequently the locomotives themselves. Let's face it these are not inexpensive models and the fact that their lifespan might be severely curtailed by the use of these motors is appalling and I wonder if they are, in fact, fit for purpose. I admire those who have the skills (and tools) to make these modifications and run these tests, but I would baulk at the idea of doing so myself. Hopefully some enterprising soul will come up with a ready to run drop-in replacement. Link to comment Share on other sites More sharing options...
PeterM67 Posted July 28 Share Posted July 28 Ideally Hornby should start retrofitting all Phase 1 locomotives that come in for repair with a carbon brush motor regardless of the reason for the repair. They should also offer carbon brush fitted motors with the associated gearing attached to anyone willing to update their own locomotives and offer to do it for anyone who feels unable. However with 12000 of these out in the field in conjunction with all the unsold stock I doubt this will happen. 1 Link to comment Share on other sites More sharing options...
dBerriff Posted July 28 Share Posted July 28 (edited) Fit for purpose is a contentious one. Model locomotives have always required maintenance and have suffered from component wear. Spares were readily available. While I find the short lifespan of these motors disappointing, the need to replace them after a while is not unprecedented. The real problem will arise if Hornby is not able to provide a good supply of spares at a reasonable price. As for "better" motors - yes please! I would be prepared to pay for the replacement but I am sure not everyone will agree. Edited July 28 by dBerriff Link to comment Share on other sites More sharing options...
Andrew-372848 Posted July 28 Share Posted July 28 That's a fair point, but the components need to be easily replaceable, these motors don't appear to fit into that category as some complicated disassembly is required. Who doesn't remember the black oily fingers when replacing the carbon brushes in our vintage locomotives. Link to comment Share on other sites More sharing options...
DJBDoug Posted July 28 Author Share Posted July 28 You only need 2 screwdrivers and a soldering iron to do this.( on this model anyway). You don’t need to remove gears. 1 Link to comment Share on other sites More sharing options...
Rallymatt Posted July 28 Share Posted July 28 TBH the end cap swap is very very easy as Doug says, basic soldering skills and some minor screwdrivering. Link to comment Share on other sites More sharing options...
Andrew-372848 Posted July 28 Share Posted July 28 ... and nimble fingers and good eyesight! But really, should one of the main components of the model be a consumable? As @dBerriff says, I would also be prepared to pay for a better motor if one were made available. Link to comment Share on other sites More sharing options...
DJBDoug Posted July 28 Author Share Posted July 28 They absolutely should not be consumables. Someone needs to send hornby all this information. At least there are “easy” options for us fiddlers. I have sausage fingers and bad eyesight and I can change these without my silly magnifying glasses. 1 Link to comment Share on other sites More sharing options...
RB51 Posted July 28 Share Posted July 28 12 minutes ago, DJBDoug said: Someone needs to send hornby all this information. ‘Tis done. R- 4 1 Link to comment Share on other sites More sharing options...
Silver Fox 17 Posted August 6 Share Posted August 6 Just received a few motors with brushes to swap when necessary. 2 Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now