Subject:
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Motor cutouts (was Re: Vincent Veneman: AMAZING building)
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Newsgroups:
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lugnet.trains
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Date:
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Mon, 7 Feb 2005 17:18:21 GMT
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Viewed:
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1600 times
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In lugnet.trains, Samarth Moray wrote:
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...
I was thinking about the weight of your models too. It seems train motors can
handle only so much, and then they burn out.
...
Legoswami Samarth
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That’s why my big diesels have 2 motors without question. It also makes life
easier if both bogies are the same (not for class 28 CoBo!).
Big steam engines have 2 motors under the tender, plus any extra ones for
driving the wheels.
Small steam engines usually double-head, which is a good thing because there’s
no room for a second motor!
The Pendolino has 4 motors - 2 at the front and 2 at the back. I deliberately
chose slightly slower ones for the back to avoid compression of the train that
would lead to derailment on curves.
I reckon to design for an average 200mA current per motor at a reasonable speed,
one that I can run at for half an hour or more. The power supply I use has an
ammeter built in, so it’s easy to see.
The Pendolino takes about 800mA at 7 Volts on a layout where it’s on a curve 2/3
of the time. It drops to about 500mA on the straight. For short periods I
might run at 8 Volts and use 1 Amp.
The size of the layout is such that the train length is limited to about 19
straights, which is only a big diesel, 3 bogie wagons of 64 studs and a brake
van. Most of my wagons are not heavy, but the cement tankers are
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=90778 since they’re sculpted
from bricks and slopes. I have only 3 of these though! If I ran a heavier train
I’d double-head big diesels.
Up to now I haven’t strained a train motor enough to have its thermal cut-out
operate!
What are the circumstances under which people have had motor cutouts operate?
Is it through crawling with a heavy train US-style, or perhaps using PWM control
(generates more heat in coils)?
Mark
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Message has 1 Reply:
Message is in Reply To:
 | | Re: Vincent Veneman: AMAZING building
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| (...) I probably should stick to things I can understand better. But still, its a nice calculation! (...) This is one thing I pondered about too. With the way they are displayed on his table, it would seem that they were display models. Yet the (...) (20 years ago, 6-Feb-05, to lugnet.trains)
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