Problematic Mainline N2 Help Required

[Smudge617]

I recently acquired a N2 in lovely condition (but very cheap) as the motor is problematic. It will only run if you remove the body and "flick" the winding housing, it runs for a few minutes then slows and then stops on it's own (it's still DC). I've given it a good clean including the armature but it still won't run without help. I have noticed that the armature gets "blackened" very quickly and one brush is arcing. I tried to replace the brushes with some spares I have (Hornby) but they don't fit as they end up jammed in the spring housing and not making contact. As the brushes may well be the cause of the problem, (or at least one I need to eliminate) I need some new ones but I can't seem to find the right ones. Anyone know the correct ones for this motor and where I possibly might find them?

I would be grateful for any help and if you have experienced a similar problem is there anything else I need to look at.

[kevinlms]

8 minutes ago, Smudge617 said:

I recently acquired a N2 in lovely condition (but very cheap) as the motor is problematic. It will only run if you remove the body and "flick" the winding housing, it runs for a few minutes then slows and then stops on it's own (it's still DC). I've given it a good clean including the armature but it still won't run without help. I have noticed that the armature gets "blackened" very quickly and one brush is arcing. I tried to replace the brushes with some spares I have (Hornby) but they don't fit as they end up jammed in the spring housing and not making contact. As the brushes may well be the cause of the problem, (or at least one I need to eliminate) I need some new ones but I can't seem to find the right ones. Anyone know the correct ones for this motor and where I possibly might find them?

I would be grateful for any help and if you have experienced a similar problem is there anything else I need to look at.

Requiring assistance to start probably indicates that one winding is open circuit. 

[Steamport Southport]

I never had one of these, but my brother has still got one.

 

As it originated from Airfix, you need Airfix spares rather than Mainline. I have a feeling the spares are the same as the LMS 4F and 2P which are still readily available from spares specialists and Hornby still do them. I think that the GWR Dean Goods brushes might also fit.

 

Hornby later re motored their version with a Hornby motor.

 

 

 

Jason

[GeraldH]

I think the N2 had the Airfix X04 style motor rather than the RIngfield style one used in the 2P and 4F.  An Airfix Prairie would have had a similar, if not the same, motor and the parts might be swappable.  The Airfix 14XX might also be a candidate.

[DCB]

The motor was the best bit of the mainline N2    Chassis wise it was one of the worst engineered models I have ever come across plastic with plastic bearings, designed to last over christmas and be dead by easter.    The motor from memory is the same as the Airfix / Mainline 61XX and I believe shares the armature with the Airfix 14XX.  The 14XX has plunger type brushes top and bottom and the N2 and 61XX   basically X04 brushes but narrower at 3 and 9 O'clock.  The class 31 armature may well be the same but with a longer shaft.   The plastic  front bearing housing is the weak point and sometimes melts letting the armature rub on the pole pieces.   

Usually these motors outlast the locos so I would try to source another motor, 61XX with smashed cylinders are often on eBay real cheap.  The brass worms need to be filed or disc cut off the good motors and drifted off the dead ones as heating melts the front bearing.

Best of luck but finding a better chassis is probably the better answer.

[Steamport Southport]

7 hours ago, DCB said:

The motor was the best bit of the mainline N2    Chassis wise it was one of the worst engineered models I have ever come across plastic with plastic bearings, designed to last over christmas and be dead by easter.    The motor from memory is the same as the Airfix / Mainline 61XX and I believe shares the armature with the Airfix 14XX.  The 14XX has plunger type brushes top and bottom and the N2 and 61XX   basically X04 brushes but narrower at 3 and 9 O'clock.  The class 31 armature may well be the same but with a longer shaft.   The plastic  front bearing housing is the weak point and sometimes melts letting the armature rub on the pole pieces.   

Usually these motors outlast the locos so I would try to source another motor, 61XX with smashed cylinders are often on eBay real cheap.  The brass worms need to be filed or disc cut off the good motors and drifted off the dead ones as heating melts the front bearing.

Best of luck but finding a better chassis is probably the better answer.

 

Seriously? Nothing wrong with it.

 

The body was decent and accurate. Notice nobody has made a kit since. Bin the bottom half and buy a Comet chassis and you'll have a good model. If you really want to go to town then get the Bradwell chassis.

 

https://traders.scalefour.org/DaveBradwell/locos-tenders/

 

Also as I pointed out it was nothing to do with Mainline apart from they inherited it from when they bought Airfix.

 

 

 

Jason

[Smudge617]

Thanks Guys, firstly let me answer Jason, Yes this is mint, no marks, cracks or blemishes in fact if it had come in the box I would have thought it to be old new stock (even though' the Hornby Guide says it was last produced in '72). As for fitting a Comet chassis, that's way beyond my skill set.

 

DCB. The Airfix 14xx motor is so so close to the one I have I nearly bought one, but the 14xx has a pin and spring on the underside which mine doesn't have, and there's no space for one in the chassis. In fact I'm at a loss to identify the motor at all. I've included some pictures so I'm sure someone on the forum will be able to identify it for me. I'm also going to put it on the Hornby Forum as well.

[DCB]

Ah ha, It looks like  the 14XX Motor with a different brush holder, not as I thought the 61XX Motor.

I would guess a 14XX motor would fit if you very carefully pried out the brush holders and fitted the N2 contact strips, You could also exchange the long pin brush holder on the 14XX for the short flat end N2 brush holder, making sure the 14XX brushes and springs stayed with the 14XX armature or of course you could file the pin off the 14XX Brush holder.   The plastic worm just slides off unlike the brass ones.   It is a long time since I had a Mainline N2 so apologies. Mine ended up as an 0-4-4 chassis on eBay .  It would have been a lovely motor except they used a metric shaft and you can't use Hornby worms on it, or nick the armature for an X04 upgrade.

 

[Smudge617]

If I use a 14XX motor and remove the long pin brush holder that would probably be easiest. I want to convert to DCC so removing the contact strips I have to do anyway. Or as you say pinch the armature from it, problem is, I don't know what's actually wrong with the motor I have, so trying to fix it is a headache.

[Il Grifone]

The brush area looks to be full of fluff and other crud. I'd clean this out and the slots in the commutator (use one of those plastic things for teeth not a needle). It should then burst into life.

I think these motors are even more indestructible than the X.04

Edited August 21, 2021 by Il Grifone

[Smudge617]

Yep, did all that when I took the motor out, (after your comment I've cleaned it again). It want's to go but there seems to be a  "flat spot" somewhere, (this seems to be where the armature stops).  If I apply power from the select it will sometimes move slightly then stops, move the armature 1/8 turn and apply power it goes but I have to have at least half power (usually full power) for that to happen, when I slow it down to just above half power and then increase it again, quite often the motor doesn't increase speed at all, so I don't know if it's the brushes or the winding or something else, and I have no way of checking.

[Il Grifone]

From what you say, it sounds like an open-circuit armature winding. Often it is the soldered joint between the winding and the commutator which fails.

Do you have a test meter? It is really essential for checking the electrics and they are quite cheap these days. I have several of these*:

https://www.ebay.co.uk/itm/323781198945?hash=item4b62dd0461:g:dYIAAOSwmUNgYVUQ

 

(They usually come complete with battery, but it's better to fit one of a decent make.)

EDIT Other sellers are available and maybe even cheaper.

 

I'm not sure of the correct resistance between the segments (it's usually between about 10 - 25 ohms depending on how the poles are connected), but as long as it's the same across all three gaps this part of the motor should be OK. There could be a short circuited turn but in this case the motor will run hot and/or smoke.

 

* Having several helps trying to find one!

Edited August 22, 2021 by Il Grifone