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Author Previous Topic: Changing siderod location on LL 2-8-8-2 Topic Next Topic: NP Intermountain FP7s
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mmagliaro

Posted - 2008 January 28 :  1:23:44 PM  Show Profile  Visit mmagliaro's Homepage
quote:
Originally posted by Chris333

The Mashima 10x12x15 has a 1.5mm shaft. You may be able to drill out the back of the gearhead to make it a press fit over the shaft.


I could do that, but I'd be very fearful of being able to drill that little plastic half-round-cavity hole out and keep it centered. I will probably (yikes!) grind the Mashima shaft down to 1mm. It's not as hard as it sounds. Just run it and hold a Dremel cutoff disk flat against it. It takes a while, but it will turn down nice and true.

Victor:
Thanks for offering.
I think I'll send you the Nigel Lawton coreless. It looks like it would come apart pretty easily from the rear. It was the best running motor, for sure (when it worked).

All 3 failed motors exhibit the same behavior:
1. Won't run. Depending on the position of the armature, they are an open or a dead short.
2. Apply voltage, turn them a little with your finger and you can get them to start.

It might be a burned out winding, not the brushes, in which case, there is little to be done to save them. But I'll get it in the mail.



-- Max

N Scale steam for the masses

Country: USA | Posts: 3890 Go to Top of Page

victor miranda

Posted - 2008 January 28 :  2:27:28 PM  Show Profile
max,
?
coreless motors have commutators...

I guess they would have to have.
I had a servo motor I pulled apart.
the shaft was attached to a basket of wire as I recall...
for some reason I can't picture the brush setup.
strange what one remembers

I'll give it a try...

the construction of finger brushes
are why you get the open or short.
if the commutator gets a grip on the finger
it will be pressed into the opposite finger...
thus a short....

v



Edited by - victor miranda on 2008 January 28 2:30:29 PM

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daniel_leavitt2000

Posted - 2008 January 28 :  6:35:12 PM  Show Profile  Visit daniel_leavitt2000's Homepage
Has anyone done a torture test of the Kato critter motor? How long do those last on testing? The implications here are larger then just refitting kitbashed engines. Bachmann is activly looking for an outside suplier for a miniture motor that could be used in their steam and switcher projects.

Goodbye and good luck.

Country: USA | Posts: 2228 Go to Top of Page

Rodneys UP 9000

Posted - 2008 January 28 :  7:21:56 PM  Show Profile
Max,
Thank for the update on the motor. I think it is great Gizomozone is interested in geting into the Model Railroad market.

I ordered 4 of the gearmotors from solarbotic. The gearbox look interesting.

Rodney


Modeling The Feather River Canyon in N-scale

Country: USA | Posts: 158 Go to Top of Page

alhoop

Posted - 2008 January 28 :  10:31:10 PM  Show Profile
Max:
Probably not related but did you ever find out what caused this:
http://forum.atlasrr.com/forum/topic.asp?TOPIC_ID=43550


Al

Country: USA | Posts: 849 Go to Top of Page

mmagliaro

Posted - 2008 January 28 :  10:37:33 PM  Show Profile  Visit mmagliaro's Homepage
Al,
I wondered if somehow the 2-10-2 motor failure was related to all of this, but I don't think
so. I think it was just bad luck. I put one of those 5-pole what-we-believe-to-be LifeLike
motors in there (like the one I used in the 5-poled 0-8-0). Visually, it was a dead-on match so it
dropped right in. It passed an overnight torture run after that, as have the 3-pole 0-8-0,
and the 5-pole 0-8-0. So I don't think I have some kooky thing in my throttle. I was wondering the same
thing, but there's just too much evidence of other engines running for hours and hours
on the same throttle to believe it.

Rodney, with out a doubt, the metal gearbox is the gem in that Solarbotics motor. It is superbly made.
When I had it off the motor, those gears would just roll with my fingers like oil on oil.



-- Max

N Scale steam for the masses

Country: USA | Posts: 3890 Go to Top of Page

alhoop

Posted - 2008 January 28 :  11:42:06 PM  Show Profile
Max:
NWSL sez never run a DC motor at more than the maximum continous rating or more than 1/3 the stall current rating.

While you wait for the Mashima why not glue the gearhead to one of the old Atlas 'can' motors(from 0-8-0,4-6-2,2-8-2 etc) and see how it works and for how long.. Size is 14.5mm dia x 15mm long.



Al

Edited by - alhoop on 2008 January 29 10:42:22 AM

Country: USA | Posts: 849 Go to Top of Page

mmagliaro

Posted - 2008 January 29 :  10:57:06 AM  Show Profile  Visit mmagliaro's Homepage
Thanks, Al. That's good data.
1/3 the stall current, eh?
The Solarbotics motor has a stall current rating of 633 ma. 1/3 of
that is 211, but I was only running it at 75. The "free running" current
(whatever they mean by that) is listed as 108ma.
So I don't think I overdid it, and still that motor crapped out.

I think these motors just aren't in the same league as a NWSL, Sagami,
or other type of "continuous duty" motor like we're used to having in a loco.

Nigel Lawton's motor is rated at 50 ma continuous, and I ran it
at 80. So, guilty as charged on that one. :-( I fried it. (But I didn't know
the rating until after I burned it out. Nigel says he'll start putting that on the instruction sheet that comes with the motor - GOOD IDEA!)





-- Max

N Scale steam for the masses

Country: USA | Posts: 3890 Go to Top of Page

victor miranda

Posted - 2008 January 29 :  1:07:52 PM  Show Profile
quote:
Originally posted by daniel_leavitt2000

Has anyone done a torture test of the Kato critter motor? How long do those last on testing? The implications here are larger then just refitting kitbashed engines. Bachmann is activly looking for an outside suplier for a miniture motor that could be used in their steam and switcher projects.



on the first version with the resistor....
I set one up pulling my christmas train.
the Kato little green engine and a two MDC passenger cars.
the Kritter was under a b-mann 36 foot boxcar.

I did not time it because I did not expect failures.
It ran for about a week. I doubt I got more than 4 hours a day but even if we double that,
it is 56 hours....
I had an mrc N500 pack on it.

I have no experience with the ones without the resistor.
v



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Rob de rebel

Posted - 2008 January 29 :  2:02:22 PM  Show Profile
Hey Max,
what they mean about free running is running without a load.

Rob


Rob de rebel
Prototrack,
rdressel@gci.net

Country: USA | Posts: 5025 Go to Top of Page

mmagliaro

Posted - 2008 January 29 :  4:18:15 PM  Show Profile  Visit mmagliaro's Homepage
quote:
Originally posted by Rob de rebel

Hey Max,
what they mean about free running is running without a load.

Rob


That's what I would guess. So in other words, I ran it, pulling a train, at a load well under their "no load" number (75 ma vs their 108),
and it burned out. So, there's more to it than just the current. Methinks the motor itself has cheap brushes, or is otherwise simply not made to run continuously.
The Mashima is on its way to me!


-- Max

N Scale steam for the masses

Country: USA | Posts: 3890 Go to Top of Page

up1950s

Posted - 2008 January 29 :  4:42:46 PM  Show Profile
Might need a heatsink , which would make it too big to use in some cases .

Richie Dost Photos http://picasaweb.google.com/up1950s


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Rob de rebel

Posted - 2008 January 29 :  5:28:40 PM  Show Profile
If its a true can with the armature running around the magnet the problem is that they don't disapate heat very well because the cover prevents heat from escaping. Not alot you can do other than get the correct rated motor.

Rob


Rob de rebel
Prototrack,
rdressel@gci.net

Country: USA | Posts: 5025 Go to Top of Page

mmagliaro

Posted - 2008 January 30 :  10:15:01 AM  Show Profile  Visit mmagliaro's Homepage
Just ran a random test to make sure I'm not nuts - since I'm taking an
engine to Timonium for show and tell, I threw it on the track last
night (a ConCor/Kato Hudson) and ran it all night. It ran just fine.

I disassembled two of the failed motors: the brushes were completely gone
and even the metal brush fingers were partially burned away, and the commutator
had deep scoring and wear. That's textbook indication of a motor that
is just hopelessly overloaded.


-- Max

N Scale steam for the masses

Country: USA | Posts: 3890 Go to Top of Page

Chris333

Posted - 2008 January 30 :  10:38:18 AM  Show Profile
Don't forget the Mashima motor from the Atlas MP15 that Victor took apart didn't have brushes, just finger wipers. (also it was 3 pole)

The same exact sized Mashima that I have (and you ordered) have brushes and 5 poles.

Maybe you couldn't burn what was never there in the first place.




http://www.trainboard.com/railimages/showgallery.php?cat=500&ppuser=3174
http://picasaweb.google.com/ErieChris333
http://www.youtube.com/user/Schmuck804
http://community.webshots.com/user/chris333333

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