Scalefour Forum

For my current kit I've got a Mashima 1020 motor - I've not had one of these before. Testing the chassis (no, it didn't run as smoothly as I'd hoped and is requiring further attention) I noticed that the motor was getting very hot. I've now removed it and run it solo, unconnected to anything, and I notice that within two minutes it is really quite hot, but not too hot to hold. Apply a little pressure to the shaft, ie running the gear through my fingers (light pressure only), and the motor gets hotter, indeed uncomfortable to hold. It's not only the motor that gets hot, its the shaft and gear as well. I should add that I've run it on both DCC and DC, both with the same results.

I've been given to believe that the 1020 is one of Mashima's most reliable, so have I just got a duff one? Or is it acceptable to run this hot?

DT

I use those motors extensively, and I've not noticed this problem.

Does the shaft turn freely with no power applied? The bearings could be out of alignment, if so try tapping the shaft end on on a table surface, both ends, to see if that realigns the bearings.

Are you expecting the motor to be used continuously for a long period?

I've use the 1024 several times, and I've never had one run more than mildly warm under load unless there was something adrift with the chassis. Not sure if there is any fundamental difference between the two but I'd agree with Tim that its worth checking the motor itself spins nice and free.

Will

Thanks for your replies. The shaft seems to turn reasonably easily with no power applied, although I couldn't say it's completely resistance-free - but there's little difference in that respect between it and a brand new 1224 I have. However, there is about 1mm horizontal play in the shaft which I suspect may not be a Good Thing. Other than overheating, the motor seems to run fairly normally And no, I don't expect it to be used continously over a long period - I'm only going to have a modest 15' out-and-back layout although the loco is destined to do quite a lot of shunting.

DT

Just a point to add to Tim V's point about tapping, I have found best results are obtained when the motor is running fairly fast, and then to tap the casing. I had a very seriously maladjusted can a long time ago, and after resettling the bearings it purred nicely.
John f

However, there is about 1mm horizontal play in the shaft which I suspect may not be a Good Thing.

That does seem rather a lot, and assuming you have a worm drive its going to be pushed hard up against one end or the other.
Keith

Having played with it some more, and tapped it (casing and shaft) while running and while not running, it's still getting considerably hotter than I would like. Also, while I thought it was running fairly normally other than the heating problem, I think I can now detect a very slight lumpiness in its running. All in all, I think I'll replace it although having googled the problem, it seems that quite a few people seem to have had problems with the 10** series running hot. Thanks everyone for your help.

DT

grovenor-2685 wrote:

However, there is about 1mm horizontal play in the shaft which I suspect may not be a Good Thing.

That does seem rather a lot, and assuming you have a worm drive its going to be pushed hard up against one end or the other.
Keith

I've had this problem with several motors and it is a major pain in the bunker to sort out as it always causes a binding whereby he loco doesn't want to move, so you increase the power then it jerks into action. Once moving it is smooth.

So far I have never been able to fix this issue and always end up replacing them.

I also have a Hornby Railroad 'Scotsman that was new given to me and it has such play in the shaft it is useless. I tried adding a collar on one end which sorted the movement out but it still is useless and destined for the repair man.

As I have started building another P4 chassis have you any ideas on how to cure this should it arise again?

I suggest washers to take up the play between motor front bearing and worm gear. Allow about 0.25 x 0.5 mm which should stop the worm chattering back and forth.

Philip

David,

could end thrust on the motor shaft cause this problem?. Most of the "gearboxes" we use rely on the motor design to take up the shaft end float and I have never experienced motor over heating, Although my locos only run for short periods now I did, for a time, own the four line test now in the hands of the NLG and never had problems when running locos for long periods.

Have you checked the current draw? Mashima motors draw very little current, especially when unloaded. High current draw with an otherwise free running motor could indicate a winding fault or possible weak magnets as the current increases to overcome friction (something I learned about with old Hornby Dublo locos).

Jol

Philip Hall wrote:I suggest washers to take up the play between motor front bearing and worm gear. Allow about 0.25 x 0.5 mm which should stop the worm chattering back and forth.

Philip

Ok thanks. Sounds an easy fix.