Williams Semi-Scale Hudson Motor Hot

I've run across several semi-scale Williams steamers with motors that draw excessive current.  When I measured the current draw with the motor under no load, it was several amps at around 12 VDC, way more than it should be for a normal DC motor of this size.

I don't have any explanation for why their motors draw a lot of current, but you aren't alone.

Thanks for the quick reply & insight, nice to know I'm not alone!

If anyone has any suggestion for a replacement motor with that long motor shaft, would love to know...

Thanks again, S/F Mike

It depends on what's in that one.  The ones that I encountered had a specific worm gear firmly pressed onto the shaft and no easy way to remove it.  If this locomotive just has a shaft to a coupling, you can find tons of similar motors on eBay, the trick is to match the voltage and RPM to what you need once you find the mechanical match.

My brother bought one of these and wanted me to add TMCC I measured the static resistance of the stock motor and it was a hair over one ohm. WAY too low for use with TMCC motor driver boards.  The stall current on 12V was nearly 12A. This is more of a blow dryer motor.  You might get that worm off with a good gear puller and a torch.  Could ruin the motor in the process though I would not consider it any great loss.  Most single motor TMCC and DCS locos have motors around 2ohms static resistance. Dual motors are usually 3~3.5 ohms.   I counted the turns on the Hudson gearbox but cannot remember the ratio. You can try and match the stock motor RPM  but if I recall it is tooo fast.  Do you know how to compute scale speed from driver diameter gear ratio and motor RPM required ?  An O scale mile is 110' about 5.75 laps on a circle of O-72. The real Hudson's top speed was not much more than 80mph 45sec/mi.   I like to run slower as scale mph laps a layout too fast.   I went through the process (mph/gear ratio/driver dia./rpm)   in an earlier post a few months ago if you want to look through my post history.   You want a little more max rpm on your motor than what is needed for your desired max speed 10~15% that will insure that you can get to the max scale speed of your locos prototype.           j

My Williams O-27 Hudson's motor got hot easily, but the motor on my Williams copy of the Lionel postwar Berkshire does not get hot.

The Hudson is gone so I cannot compare motors and gear ratios.

I'm pretty sure I counted the gear ratio as 13:1.  It's easy to check for yourself turning the flywheel by hand, and note the position of the driving rods.

These are geared much taller (faster) than RailKing (17:1 and now some 26:1); LionChief (18:1 up to 25:1); and K-Line semi-scale (probably 18:1).  My experiments show that these RS-385 motors can easily reach 9000 RPM in a model train application.  With 13:1 gearing and 1.375" drivers, top speed for the Williams is almost 150 scale mph!   That leaves a lot of slow-speed performance on the table.  For example, I doubt one of these would maintain a steady 10 mph, running light from straight track into O31 curves. 

As others have said, removing the gear and replacing the motor isn't an easy repair.  My $.02, but I would be saving for THIS or THIS.

Well, not all Williams Hudsons have the same motor. My pre Bachmann Hudson draws 1/2 amp w/o lights or smoke unit running light. 

Pete

I know I've seen at least three of these with a motor that sucked power like it was going out of style, the clue was when my test bench breaker popped immediately when I gave them throttle!

gunrunnerjohn posted:

I know I've seen at least three of these with a motor that sucked power like it was going out of style, the clue was when my test bench breaker popped immediately when I gave them throttle!

Just some insight from my experience.

When I worked on a driver for Atlas O, testing showed the twin motored unit stall current was only 4.1 amps. Obviously motors from Mabuchi.

Know that there is a Chinese company that does Mabuchi knock-offs.  Their name is Hing Lung Motor Manufacturing.  https://hinglmm.en.china.cn/

Tried using their mini 5V motor on the TAS smoke units.  Not so good.

Regards,

Lou N

Interesting Lou, the motors I recall are not labeled as Mabuchi, and they're typically black.  They may be a "brand-X", likely why they didn't work well.

Thanks John & all for the ideas and info.  I'll check this out!  I think the challenge may be in finding a suitable motor that comes with a long motor shaft.  The engine cab will allow for a slightly larger motor can.

Other option it remains a nice looking engine for short running times...

Thanks again & S/F Mike