Motor Maintenance

[Mike W]

Hi all - first post and all that.

Am getting into racing for the first time having played with Tamiya R/C and the like for years, but never anything competitive.
So have now got myself an RC10 B4 and got a new motor for it this week - a Fantom racing P series 12 double.

Only thing is this plunges me into the area of motor maintenance, which was something that never really came up with my previous R/C experience.

Does anyone know of a good guide to motor maintenance, and have any suggestions on reasonably priced tools to do it?

[Mike W]

Erm, anyone? :confused:

[scott_davis]

Have a look at the FAQ's Mike - If you are still stuck then post up specific questions.


Scott

[Mike W]

Erm, dunno if I'm being thick here, but what FAQs?
The FAQ link at the top seems to be just vbulletin software FAQs.

[scott_davis]

It doesnt look as if there is a FAQ section for motors! :eek: :confused:

What is it you need to know? - I do all my own maintenance so can probably help.

Scott

[axpayne]

Hi Mike,

the main things to check on motors are, brush / comm wear and that the bearings in the endbell and can are running smoothly. Having you taken the motor apart yet and do you understand the terms brush and comm?.

It can all be explained online, but is easier to discuss it directly with someone where you race.

other than a screw driver and soldering iron the other main piece of equipment is a comm lathe. These cost around £200. I would expect one of the experienced / top racers at your club to have one of these who would skim your motor for free or a small charge. Unless you are planning on doing alot of racing, don't worry about getting one at this time.

Andrew

[Mike W]

Haven't taken it apart yet, but I know where the brushes are, and am pretty sure the commutator is the surface they contact against?

Just want general tips like how to know when the brushes need changing, realistically how often the comm needs skimming, even how often it needs cleaning etc.

Have heard different things varying from every time you run it to whenever it sounds like it needs it!

[scott_davis]

This is what I do and is not necessarily what everyone does – some people do more, some people do less but I hope it will help you with regards to motor maintenance.

You WILL need the following:

A Lathe (or access to one)
Brushes for the motor

I inspect the comm. And brushes for pits / wear, etc every 3 runs approx. If any wear to the comm. / brushes that does not look normal I remove the motor and re skim it on a motor lathe. If brushes are ok I re use them otherwise I replace. Always solder brushes direct to the endbell.

When skimming comm. On your lathe always ensure you know which way round the endbell goes back on and mark the timing before dismantling the motor – I always use the sticker as a guide and scratch the end of the can on both sides where the screws are to give me alignment marks. There are timing marks on most motors but its easy to forget which ones were used after dismantling it! 

Stripping down a motor is very simple:

- remove the springs and brushes from the brush holders
- remove the screws holding down the endbell to the can (mark your timing first)
- Gently pull off the endbell watching any stray washers that may come off
- Remove the armature from the can again watching any washers that may come off

You then need to clean out the can – I just use some soft kitchen towel – I am not a fan of using sprays to clean out the can as you can dry the bearings out but I do use some motor cleaner with a cotton bud to clean out the endbell brush slots, etc

Then its time to mount your armature on your lathe – ensure there is only a little side play when the armature is mounted on to the lathe. You don’t want it moving around! – use some of the motor washers if necessary…. The idea is that you cut the minimum amount off the comm. To get a nice shiny un blemished finish! – I tend to first make sure the comm. Is un blemished then I do a final run by just nudging the dial about 0.1mm and going from left to right. That usually gives it a nice shiny finishing coat.

Note if the lathe is ‘spitting’ off the comm. Then you could be taking too much copper off or it could be that the comm. is not ‘true’ – not un-usual for brand new motors having their first skim.

Once the armature has been skimmed I remove anything from the comm. slots and ‘score’ the slots using a biro pen – this will help the brushes last longer and prevent them from chipping the brushes / burning the slots.

Then its just a case of putting it back together and making sure there is not too much (or too little) end float in the can – you can adjust this by removing / adding washers…. Just ensure you put a plastic washer above the comm. to prevent shorting!

Ensure endbell is on right way round to prevent embarrassment on the start line! And make sure you line up the endbell with the timing marks you have….

You can adjust the timing if you wish but its not something I do – you would be better off asking some other guys who play with timing / springs / etc but for a beginner to motor maintenance I would stick with the stock settings for now and concentrate on keeping the motor in good condition.

Some motors will require less skimming / maintenance than others – but it is important you skim regularly (6 runs is the average) as this will make the comm. last longer and the performance will stay consistent. You could leave it longer if you wish but it is possible you would have to take a lot of copper off the comm. to bring it back to the required standard.

I hope this helps!

Scott

[Mike W]

Thanks, that should be useful.