I recently acquired a Mantua General and four W&ARR cars a few days ago. The locomotive is DC with the motor in the tender, which turns the drivers via a drivesaft, universal, and worm gear. The loco had been sitting for a while before I got it, but I cleaned and oiled it, and made sure everything was working properly before putting it back together. The loco is in really good shape both cosmetically and mechanically, except that after about 8 to 10 minutes of running it starts to slow down and the motor gets really warm, or outright hot. The motor is original. The driveshaft and drive wheels roll smooth with no stiffness or binds when turned by hand, and there aren’t any shorts either, as I have an MRC 2400 series power pack that has a circuit breaker that trips when there is a short. So my question is, is the motor going bad, or is there something I might be missing? Or, should I just look into putting in a can motor? Thank you in advance for any and all input.
I have a 1890 Rogers 4-6-0 that was doing the same thing. I replaced the magnets, cleaned, and lubed the motor, but in the end I replaced the motor.
It may be easier to find a small can motor that fits with a tender drive, rather than the narrow frame of these old locos.
I may just do that, because I put in a little Pittman motor that fits and that I had on hand, and while it runs smoother now, it still seems to be getting warm a little too fast. Maybe there just isn’t enough airspace inside of it for open frame motors. Thank you for your advice.
That engine’s motor (tender shell) always did get hot because there was so little in the way of “air” around it. It especially got too warm if you used “pulse power” which tends to make any motor warmer. It sounds like you have already checked out the other common cause of overheating in The General and other Mantua locos, that being side rods that bind a little bit. The original kit construction involved futzing and futzing with the side rods until the loco by itself rolled smoothly before installation of the drive train/tender motor.
I have some recollection that guys used to try to make the area above the motor (the “wood” load) opened up for a bit of venting.
It may be that the magnet is weakened as well but even with a fresh magnet the natural heat involved with the motor does not have anywhere to go in an as-built General.
Dave Nelson
I was kind of thinking that might be the case, because I put in a Pittman motor, and it gets warm too. Just not as warm and not warm as fast, so I’m going to leave it in as it does run more smoothly.
I was thinking about doing that as well, and reading that other’s have tried it says to me that it’s probably the right course of action. Thank you for suggesting that.
I’ve been trying to respond to this post multiple times, but there have been ‘gremlins’…
As I recall there was some discussion of this on the Civil War Railroads Yahoo group (now on groups.io). The idea is to make a wood load from stock wood, with an open ‘weave’; you can use dark mesh or fabric underneath if anything ‘shows’. Best to put some holes/slots in the chassis for through-ventilation.
Overheating the motor has probably had a progressive demagnetizing effect on the motor, and I wouldn’t hesitate to change it out for a high-strength replacement (which will reduce the current passes through the armature to make torque at low speed, and so contribute to reduced heating). Periodically check to be sure the new magnet is retaining its strength…
That seems to be happening a lot lately. I have that issue about once a month or so.
Thank you for the good advice. I’ve replaced the fake wood with real wood on most of my other wood burners, so I’ll definitely be putting in some vent holes before I add the wood load. It will look a lot better too.
Do you have an ammeter to check on current draw? When one of these is running smoothly with no binds or tight bearings, it shouldn’t use more than about 0.35A with the old motor.
When I built my General kit, I ended up replacing the motor with a coreless one that fit nicely into the tender. The current draw is so low that it can run all day without even getting warm!
Some years ago before Mantua was bought out, they had motor upgrades for the General and I bought one. I think it was a flat can, abut 27mm x 15mm x 12mm… 1.5mm shaft as I recall. You should find near equivalent on ebay.
I found near the same for my Bachmann in old CD drives a few years ago.
I keep a dial caliper handy.
Rich
I don’t have an ammeter, unfortunately, but I should probably look into getting one.
Thank you. I’ll have to keep an eye out for that.
There are a huge number of inexpensive motors available on eBay, Aliexpress, etc. You could look around for those aproximate dimensons.
Mel (@RR_Mel) is very knowledgeable about motors; he tends to model big stuff (cab forwards), but he may have a suggestion for you.
If $50 is a reasonable budget, you might google ‘MRRHQ General CanDrive’ and see what develops…
That’s something I’ll have to bear in mind down the road.
Update: As per Dave Nelson’s and Overmod’s suggestion, I removed the tender shell and drilled eight or nine vent holes in the top, and then disguised them with a new wood load and it seems to help quite a bit. It still gets a little warm, but not as warm and not as fast. I should also mention that the weather has been on the hot side lately, and I live in a 112 year old house that doesn’t have airconditioning, so that may be a contributing factor. Thank you, everyone, for your helpful tips and suggestions.
I have used meters since 1955.
The past ten years I have used the below and put the expensive ones away.
I have four of these.
http://www.trainelectronics.com/Meter_Workshop/index.htm
I keep one in the garage for the car. I have different clip lead sets. One is for a DCC amp meter.
Rich
Sorry to hijack this subject, but with the number of people contributing I thought I’d ask, where do you get replacement traction tires for the Mantua General? Mine have perished to the point where they are unuseable. Also I’m in Australia.
You can order them from these guy’s.
https://www.theoringstore.com/index.php?main_page=page_2&zenid=ce9c72479636045d32bc2557449eae0c
T.C.
Thanks TC
If may revive my thread one last time, I just remembered that I have an old CD drive from a retired computer in my garage. Is there anything I need to be cautious with when taking the CD drive apart, or can I just have at it and get the motor out?