Building Electric Motors from Scratch ?

[siltec]

I have an old book on model electric railways and the option of building ones own electric motors is covered.

 

Anyhow I have recently been servicing some old Hornby motors and had not realised the simplicity, especially the way they are built into the chassis. With a permanent magnet all that has to be made is the armature. Now I also acquired an old book on building your own motors and dynamoes. It has some standard sesigns and interestingly the 12 volt option has a size not far off those used by Hornby. To be honest I thought they would be bigger.

 

From a modelling point of view the tricky bit is the laminations. However, chemical milling, wire and lazer cutting are all methods for short production runs.

 

Just wondered if anyone has had a go at motor building? In these days of everything off the shelf I reckon there is going to be a bit of drift back to basics.

[Xerces Fobe2]

The question is why would you do this?

 

XF

[Neil]

As an apprentice electrician with BREL back in the seventies, a low voltage dc motor was one of our standard practice pieces. I remember very little about its construction apart from it was from scratch (machined our own commutators, that sort of stuff) and that the biggest pain was winding the armature. We had a hand cranked machine that was supposed to help accomplish this task, but it was a temperamental b*gg*r.

[Guest]

I made one years ago using a pantograph to create the laminations and wound the armature on a lathe with backgear engaged, the only bought in part was the magnet. What I ended up with was a motor that was weak, ran hot and never got used.

 

Not trying to put you off, it was an interesting project at the time.

 

Regards

Pete

[siltec]

The question is why would you do this?

 

XF

 

Curiosity. I used to work in a factory making electric motors, big ones, mainly AC synchronous. Mind you at one time they did make DC traction motors. Long time ago; site is now a B&Q and Morrisons.

[Nigelcliffe]

I started making one many (20+?) years ago. Then I found a commercial motor which would fit the loco in question. As a side-effect I edited a short paper on making small motors, which is available via the 2mm Scale Association; this pulled together the work of various 2mm scale pioneers who had little choice but to make their own motors.

 

 

- Nigel

[Horsetan]

..... I edited a short paper on making small motors, which is available via the 2mm Scale Association.....

 

I can confirm it's a fascinating read, particularly the part describing coreless motors.

[JeffP]

I remember an interesting article in a VERY early edition of MRJ in which the author described how he modified a simple motopr to skew wound. It was 50% more powerful.

[kevinlms]

I remember an interesting article in a VERY early edition of MRJ in which the author described how he modified a simple motopr to skew wound. It was 50% more powerful.

 

Was that 'Upgrading small motors' in MRJ No. 22? Using Mabuchi motors, this one I think

 

http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=sh_030sa

 

Making it skew wound would make it less susceptible to cogging, other changes would need to be made to increase its power, if the little that remains of motor theory is still right.

 

Kevin Martin

[micknich2003]

There have been many articles in the model press on building motors. Possibly the best by the late Sid Stubs in the "Model Railway News" c1964, I don't have the exact dates to hand. Sid was a electric or mechanical engineer by proffesion, so should be the business. Whatever, his models certainly worked. Mick.

[bundeena2230]

Back in the 70's when I did my apprentiship in electronics, my (soon to be) wife's father was a real Aussie bushman, wound his own transformers and all.

He was constantly asking me to help him make such things, especially as his boys were mad into model cars - 12v

The biggest problem we encountered here was making the thing balance at speed, worked almost well when slow, but wanted to destroy itself as you wound the wick up.

My advise to you would be in ensuring you got the mechanics working before you wind the armature, connect your black and decker drill to the end and run it up to see if it holds together before you add the brushes or wiring.

 

But I agree with Xerces above, the time it takes versus the return is not worth it in my book, but if you have never done it before, why not.

K

[34theletterbetweenB&D]

The few motor rewinds I have done now lie many decades ago, to a time when motors were relatively more expensive. What really helped was prior experience of making windings used in high fidelity audio equipment (which was also expensive) which was and remains my Dad's main hobby. You can actually hear the difference as your winding technique gets better...