Best Of The TP56/TP70 Kitbash thread N scale

[Chris333]

Ron, wondering why you didn't just put the worm on the motor shaft and slide the motor in about 1/2"?

[u18b]

Ron, wondering why you didn't just put the worm on the motor shaft and slide the motor in about 1/2"?

Chris,
Great question.

I don't think the shaft is long enough.
At the very least, the truck worm cover must be cut for that to even happen.
And I in essence did not want to ruin the truck if this did not have a chance to work.

I have another truck from the donor SD40-2 and another 11-105 chassis, so I might go for it.

I was thinking of buying some more motors to try.
But they come from China, so another month of waiting.
But these are cheap and the shafts are longer.

http://www.ebay.com/itm/2PCS-Mitsumi-FF-M20-DC-1-5V-4-5V-3V-4000RPM-Micro-Mini-Metal-Brush-10mm-DC-Motor-/262740164075

http://www.ebay.com/itm/262550362464?ssPageName=STRK:MEWAX:IT

[Philip H]

Chris,
Great question.

I don't think the shaft is long enough.
At the very least, the truck worm cover must be cut for that to even happen.
And I in essence did not want to ruin the truck if this did not have a chance to work.

I have another truck from the donor SD40-2 and another 11-105 chassis, so I might go for it.

I was thinking of buying some more motors to try.
But they come from China, so another month of waiting.
But these are cheap and the shafts are longer.

http://www.ebay.com/itm/2PCS-Mitsumi-FF-M20-DC-1-5V-4-5V-3V-4000RPM-Micro-Mini-Metal-Brush-10mm-DC-Motor-/262740164075

http://www.ebay.com/itm/262550362464?ssPageName=STRK:MEWAX:IT

How do you limit current on these motors?

[Chris333]

Also was wondering when the Kato chassis came with something other than a 12 volt motor 

[u18b]

Also was wondering when the Kato chassis came with something other than a 12 volt motor 

When they first came out, they had a 3 volt motor.
And a big old 100 ohm resistor mounted under the motor.

[u18b]

How do you limit current on these motors?

Kato has nothing, so I figured I would use nothing.

By the way, because these are rather fast, the decoder is only sending out about 50% of the juice.  (Vmax)

So do you think it needs something extra?

[Chris333]

About the motor shaft. You could push the worm shaft half way out and glue the motor shaft in. The motor shaft doesn't have to go all the wat through. I assume the clip holds the worm in place.

Always just ideas. Don't even know if you need the extra room that pushing the motor in would get you. I guess in a way putting weight around the drive shaft might be better and closer to center.

[mmagliaro]

Kato has nothing, so I figured I would use nothing.

By the way, because these are rather fast, the decoder is only sending out about 50% of the juice.  (Vmax)

So do you think it needs something extra?

Should be fine if you let the decoder limit the top voltage.
That Mitsumi, I think, will work well.  I'd be interested to see how that goes if you get one.  Only 4000 RPM top speed.  That's about 1/3 of the top speed of a typical model loco motor.  So it may have really good torque at lower speeds than
other low voltage (i.e. 3v) motors.

[Chris333]

check out this square motor:
http://www.narrow-japan.com/productsNG.html#SE15HORTYP
http://narrow.d.dooo.jp/SE15HORTYP.html
http://narrow.d.dooo.jp/Part.html

[randgust]

It's been a long time since Kato did the 3V motor - maybe....2007.  The legacy of that motor is the little circuit board underneath - that's where they put the 100-ohm resistor.   That worked... but on a low-torque situation as the load decreased the voltage increased and the thing would take off underneath of a throttle.  You'd get to the top of a grade and as soon as it hit the flat it would just accelerate on its own.  Taught me to hate 3v motors with resistors UNLESS you had enough of a gearhead to negate the torque issue.

Ron and I are using the same motor here.    That motor shaft is too short to put much of anything on.

However, the Bachmann 44/70 tonner motor (double shaft) has a much longer shaft to play with and a worm already on it, very similar motors.   I think it would be possible to use that motor, maybe even with the original worm on it..maybe...

http://estore.bachmanntrains.com/images/n_parts/N818x-10185.JPG

I've got one but haven't tried getting that worm off either.

Now, one thing I have done on the Kato 11-105 motors is to cut a bit off the back of the plastic universal on the motor end - most of the taper - and if you do that on both ends of the universal you can move the motor in almost a scale foot or so.  That might make the difference here.   I have to do that on my Climax conversions of the Kato chassis to fit the gearhead motor in.

These are really amazing little motors and for a page-size finger-brush design, are amazingly durable.  I've never had one fail on me, and I've had multiple failures on other finger-brush designs.  But there's no miracle here, they are fast, and can produce only so much torque.   When I use them in a 'stock' Climax conversion on that Kato chassis, I can get the speed down to about 10mph, but the typical Climax topped out about 12.   You're struggling with the throttle to keep it moving at the lowest setting possible.   Depends if that bugs you or not, your call, but when you're taking a project like this on, you're fighting physics on several fronts!

My ultimate nuts-tiny gearhead I used for geared steam conversions on that chassis - 3v, but absurd torque:
https://solarbotics.com/product/gm15a/

[u18b]

Here's a video.

Shows how smooth this runs- except at very creeping speed.

[narrowminded]

That doesn't look bad at all.  Are you using a pwm controller? Something that is low frequency like a Veri-Pulse or Medvend unit does a pretty good job with low speed control.

[160pennsy]

That doesn't look bad at all.  Are you using a pwm controller? Something that is low frequency like a Veri-Pulse or Medvend unit does a pretty good job with low speed control.

Since it has a hardwired Digitrax decoder I imagine it's a DCC throttle

[u18b]

That doesn't look bad at all.  Are you using a pwm controller? Something that is low frequency like a Veri-Pulse or Medvend unit does a pretty good job with low speed control.

Got me. 

I'm running a Digitrax DZ126 with a MRC Prodigy DCC system.
The speed steps is set at 28.

Starting CV2 is set at 6 to give it a little jump from dead stop.
CV5 max is set at about 80
and CV6 mid is set at 40.

All of the rest of the settings are stock.

[u18b]

Remember, that it ran pretty well under mt MRC Railpower 1400 DC/analog throttle.

But it ran hot from the pulses.
The motor would have eventually burned up.

DCC is the way to go with this little motor.