Subject:
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Re: Smooth power or PWM for Lego train motors?
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Newsgroups:
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lugnet.trains
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Date:
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Thu, 4 Sep 2003 21:49:13 GMT
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Reply-To:
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javanree@vanree.+nospam+net
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Viewed:
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1830 times
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Mark Bellis wrote:
> Yes, I've had a 9V conroller apart and drawn the diagram. I was thinking
> of using an outboard pass transistor (2N3055 or similar) in accordance
> with the
> LM317 data sheet. Horowitz and Hill show how it's done, but I haven't had
> time
> or enough motivation to build it yet. The transistor would need its own
> heatsink outside the box, so it might get untidy, needing more effort on
> the
> enclosure. I think the max output of the transformer is 300mA. The limit
> on the British wall transformer is 7VA - 0.78A resistive at 9V, minus the
> losses in the controller.
You could also simply swap the LM317 for a heavier type (LM317K for
instance), which could give you around 1000mA uncooled without much issues.
Together with Klaas Meijaard we cut up an old home computer power supply,
giving 2*11VAC at 22 VA, we hooked up a LEGO controller and managed to have
a train with 8 engines running, without modifying the controller (did stop
working after around 15min, thermal protection) So the controller doesn't
seem to be the limit, but the wall transformer.
--
Jan-Albert van Ree | http://www.vanree.net/brickpiles/
Brick Piles | Santa Fe B-unit
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Message is in Reply To:
 | | Re: Smooth power or PWM for Lego train motors?
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| (...) Being British I'm not too familiar with American trains (yet), Though I know about the multiple engines in real life. I would intend to triple head trains in a similar way when I have made enough American engines! The motor duty limitation is (...) (21 years ago, 4-Sep-03, to lugnet.trains)
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