Chapman GP7 Project

Re: Chapman GP7 Project

Postby krokodil » Mon Oct 10, 2016 12:20 pm

0.023 in is about 0.5 mm what is still quite critical how exact is the motor position in the frame and how exact is the hood position on the frame. Maybe you can remove some material from the inside of the hood ( only in the area where the motor body is). In worst case you can glue a very thin aluminium or copper foil inside of the hood to distribute the heat from the motor body.
It also depends also from the motor how many heat is generated at normal operation.
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Re: Chapman GP7 Project

Postby ConnRiver » Mon Oct 10, 2016 12:23 pm

So, it is going to require testing, more testing, and even more testing. Maybe let the locomotive, once broken in (necessary to do this for the motor?), run for a couple of days?
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Re: Chapman GP7 Project

Postby krokodil » Mon Oct 10, 2016 1:36 pm

Unfortunately there is no general solution. There are motors using to run quite hot and there are motors they will be only warm after few hours of running. It depends on the load (gear and train) but also from the power source - simple analog throttle or sophisticated PWM or DCC power. The last ones usually generate more heat on the same motors.
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Re: Chapman GP7 Project

Postby ConducTTor » Mon Oct 10, 2016 1:55 pm

ConnRiver wrote:Alex, originally I assumed the Mashima 1224 motor and drew it first. You recommended against it. Somehow, I landed on the Mashima 1020 motor, but rather than the 1224, did you recommend the 1220 (and not the 1020)?


The main difference between the 2 is the length of the motor. As for performance specs, they are virtually identical.
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Re: Chapman GP7 Project

Postby krokodil » Mon Oct 10, 2016 2:08 pm

The bigger (longer) motor is always better......y
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Re: Chapman GP7 Project

Postby sd80mac » Tue Oct 11, 2016 6:31 pm

Hi Brian, I also went on AliExpress and incidently ordered 30 "Kato clone" motors for several HO-scale projects while looking for the TT-scale motors. The black motor that I posted was $7.00 each from the AE supplier, but I went on eBay and saw the same motor at a cost of 2 for $5.10. So, I ordered 4 motors @ $10.20 and they will be here toward the end of October. Also note that these motors have 2mm shafts as opposed to the 1.5mm shafts on the Mitsumi.

Lastly, I saw that Krokodil mentioned that a longer motor is better. So, I did come across this one:
ImageImageImage
http://www.ebay.com/itm/DC12V-24V-Dual-Shaft-Strong-NdFeB-Magnetic-Mini-Motor-for-RC-HM-Toy-Car-Boat-DIY/122039567928

Do you think it could work? It's 10mm longer than the first black motor, and almost 15mm longer than the Mitsumi motor.

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Re: Chapman GP7 Project

Postby ConnRiver » Tue Oct 11, 2016 7:21 pm

Donnell, a TT scale hood is 0.6 in. wide, figure .040 in. per wall, that leaves an interior width of 0.520 in. to accommodate a motor. And, we want a bit of space between motor and walls, too. What's the width of that motor?

The longer the motor, the less metal that will can be used in the frame. Even tradeoff?
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Re: Chapman GP7 Project

Postby sd80mac » Tue Oct 11, 2016 7:39 pm

12.7mm, the same width as the shorter motor.

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Re: Chapman GP7 Project

Postby ConnRiver » Sat Oct 22, 2016 6:52 pm

Just a quick word. I've kind of trailed off here some, waiting for the Mitsumi M15N-3 motors to arrive. Playing a bit with creating a 12-inch flex track section to be CNC milled (gotta get some track built to test the power chassis) and re-familiarizing myself with the R-40-10 reefer project.

Thought I should provide a note since it's been quiet here for several days.
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Re: Chapman GP7 Project

Postby ConnRiver » Tue Nov 01, 2016 2:14 pm

STILL haven't received the Mitsumi M15N-3 motors I ordered. Geez.

Guess I better get to work getting the shop in order, getting the spin-caster and vulcanizer lugged down to the lower level. Hey, any of you guys who can get over here and lend a hand, come on! Caveat: I'm not responsible for any hernias incurred. . . . That stuff is very heavy.
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