PRR H10 Remotor

[nscaleSPF2]

I was able to obtain some temperature data, using a fairly inexpensive infrared thermometer.



This device proved easy to use, and gave pretty consistent data.  I held it 3 to 4 inches away from the motor, pulled the trigger, and scanned over the surface to get the highest temperature, which proved to be near the rear bearing.  The temperatures recordered were on the outside, of course.  We don't really know what the internal temperatures were.  Here is the data, with the engine pulling 15 cars on level track at 3/4 throttle.

Time.       Temp.
1min.       98degF
2.            109
3.            111
4.            114
6.            123
8.            122
10.          128
15.          133

At the end of 15 minutes, the motor was indeed very warm to the touch.  This is also consistent with some Internet research; I found that you are not supposed to be able to hold your finger on a metal object that is hotter than 140degF.

So what does the data tell us?  For one thing, I think that Victor said that a high temperature very soon after the engine starts to roll indicates that there is a binding in the drivetrain.  That does not seem to be the case here, so I think that we are ok for binding issues, at least for now.

Also, even though we do not know the internal temperature of the motor, I'm thinking that it can't be that high, given that the external temperature only got up to 133 degrees.  If I had run the engine longer, the temp would probably have gotten up to 140deg.

Anyone have any thoughts on this?

[mmagliaro]

My thought is that the rise in temperature really started to level off there at the end, rising only 1 deg per minute.
So I'm not sure that it would ever reach 140.  Maybe, but I sort of doubt it.  I think you were reaching the peak there.

I agree with Victor's opinion... if the heat rises quickly on startup, it's probably not because it's pulling too many cars up a hill.  The motor would have to be severely overloaded to cause such a quick rise and that would imply a bearing or other bind.
So I don't think you have that problem.

It's hard to know what the normal expected operating temperature of that motor is.  It could be running at
the peak of its capacity, or it could just be built to run hot.   But I've used Mashima 1015's in other engines, even a
Bachmann 2-6-6-2 remotor job, and I don't recall it getting uncomfortably warm like that,  even with it
pulling 30-40 cars.   The 2-6-6-2 is geared down pretty well, but then, so is the Spectrum 2-8-0.
So I am still wondering why all the heat.

[victor miranda]

Of course I am going to jump in!

COOL Gizmo!

the rear bearing being the warmest indicates the armature is the source of the heat.
the motor magnets are getting warm, just not as fast.
the other thing is you may want to try to hunt a speed/load where the temperature stabilizes.

lower the throttle or take off a few cars and run that same test.
my opinion is that 3/4 throttle and 15 cars requires too much power for the motor to supply.

it is close, in that 15 minutes and 140 degrees is not a dangerous combo.
if 14 minutes was 138 and minute 16 was still at 138 I say it has stabilized
and while hotter than I'd like, it is serviceable.

my other opinion is that the motor can survive at 180.... and your model if plastic will melt.

we have to find a way to get the current draw down a touch...
I have to think a bit.

victor






 

[nscaleSPF2]

Thanks for your responses, Max, Victor.

Max, was the 2-6-6-2 remotor powered by DC or DCC?  Do you think that this would make a difference in the amount of heat that the motor generates?

The other cause for the heat may be that I damaged the motor when I Loctited the motor shaft to the forward bearing.  I applied 12 volts to the motor while it was stalled, for probably less than 1 minute.  If I did damage the motor this way, then I am just going to run it until it stops, then replace it.

Meanwhile, the engine is finished, except for paint:







A small part of the motor still hangs out of the back of the cab.  Hopefully, once the tender is installed, this will be less noticeable.

[victor miranda]

you are done with the easy part.

blowing paint onto all that hard work is the toughest part.

I have grown familiar with sagging paint.
it adds character!

ooof

luck in your painting and decaling.

victor

[Cajonpassfan]

Jim, that is very very nice, even magnified.
As to the motor, may I suggest a closely coupled tender and canvas curtains in the cab?
Nice work; Jason will be proud
Otto K.

[nscaleSPF2]

Thank you, Otto, for your kind words.

you are done with the easy part.

blowing paint onto all that hard work is the toughest part.

I have grown familiar with sagging paint.
it adds character!

ooof

luck in your painting and decaling.

victor

victor,

painting, like everything else in life, is very simple.

it takes a few basic principles and lots of practice.

make sure the surface is clean.
thin the paint.
apply a few very, very light passes (with an airbrush).
let dry and apply a few more passes.
repeat.

you can find any number of forum threads to describe the process.

bottom line is you have to find what works for you.
and practice.

could this be a use for the roundhouse queens that you have lying around?

respectfully,

Jim

[mmagliaro]

+1 on the curtain to hide the back of the motor.
I've used that trick a few times.  It's like making lemonade out of lemons.  It doesn't just hide
the motor.  It makes the engine look better!

Loctite in the forward bearing...  It's really hard to say if applying current and having a stalling motor
for a while could permanently damage it.  Magnets can lose their magnetism if they are overheated.
And it could be that some Loctite is making the shaft turn in that bearing less freely than it should.
I do know from getting Loctite into places where it doesn't belong, like a bearing/axle surface, that it
is surprisingly hard to really get it all out of there. 

I think your approach of just running it and being prepared to replace it if it ever fails is sound as long as you are prepared for that possibility.

The 2-6-6-2 I did was straight DC.

Oh, and by the way, this is long overdue, but your engine really does look very nice.  I look forward to
seeing it painted and lettered.  I really like the air reservoir.  And that brass pipe with the knobby thing
on the end of it, on the left side, coming down from the dome, bent in an "L" shape -- is that a
"repurposed" Precision Scale brass detail part?   

[nscaleSPF2]

Oh, and by the way, this is long overdue, but your engine really does look very nice.  I look forward to
seeing it painted and lettered.  I really like the air reservoir.

Thanks, Max, that means a lot, coming from you.

And that brass pipe with the knobby thing
on the end of it, on the left side, coming down from the dome, bent in an "L" shape -- is that a
"repurposed" Precision Scale brass detail part?   

The brass pipe is a wire that was bent to replace a cast resin part that broke off during handling.  This seems to be one of the few disadvantages of these castings.  The knobby thing is part of a brass grommet that simulates a coupling to the remaining part of the casting.

[superturbine]

The engine is looking very nice Jim.  And yes Otto, I am proud to have made a small contribution!

[Cajonpassfan]

The engine is looking very nice Jim.  And yes Otto, I am proud to have made a small contribution!

Lol Jason, "small" in scale only!
Glad to see you back, if only lurking right now 
Call me when you have time to chat.
Best, Otto K.

[nscaleSPF2]

Project update.  Tender is complete, except for paint.



Lots of very nice detail, that does not show up in the photos.



Dimensionally, the tender is very close to the prototype.  The trucks are also spaced to get the proper wheelbase.

Verne is back in the shop, working on the drawbar.  Who knows what he'll come up with.

[superturbine]

Looking really nice Jim!  Keep up the good work!

[nscaleSPF2]

This is how the draw bar turned out.  It is about 0.20 inches shorter than the stock one, shown above in the photo.



The draw bar is made from .032in ABS, glued together with Plastruct cement.  I dribbled some cement into the 2 holes, to make a stronger bond.  This should be more than strong enough.

Jumper wires were soldered to the ends of the phosphor bronze wires, like so.



I added a bit more lead to the tender; it's weight is now up to about 1.5oz.  The extra weight plus the jumper wires has just about eliminated any issues with electrical continuity.

The boiler and tender shells should be out of the paint shop soon.

[nscaleSPF2]

As promised, here are some photos of the finished locomotive.  Sorry it took so long.







Where did the motor go?  There it is, behind the curtains.







If anyone is interested, I may try to figure out how to shoot and post a video.