Subject:
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Re: Electrical Things (was: Railroad Dilemma)
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Newsgroups:
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lugnet.trains
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Date:
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Mon, 8 Mar 1999 14:21:36 GMT
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Viewed:
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2379 times
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> I'm not sure I agree that the voltage is variable. People have reported
> (via oscilloscope analysis) that it's pulse width modulated 9V instead.
> This will read on an analog meter like a low voltage, because it's
> taking the average across time.
If you have any URL's where people have reported on this, I'd be interested.
> > The motor power unit has a resistance of 8.7 ohms, so at max. speed, it's
> > eating up about an amp. (or about 9 watts of power).
>
> How did you measure that resistance? Ohmmeter across an unpowered motor?
> I don't think an amp sounds right. You can battery power these motors
> for a good long while on 6 AA batteries. I bet the resistance is a bit
> higher with voltage applied.
Yep - it was ohmmeter across unpowered moter. I did think about directly
measuring the current with the motor running, but my multimeter has a
maximum current rating of 0.2A - so the voltage and resistance readings
I was getting were kinda suggesting I'd probably trash my multimeter if I
did that :) If the resistance does increase with an applied voltage, that
might explain why I couldn't get a consistent calculation for the
transformer's internal resistance.
Simon
http://www.SimonRobinson.com
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Message has 1 Reply:
 | | Re: Electrical Things (was: Railroad Dilemma)
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| (...) So would I, because it's not true! As I've said this many times, it's plain and simple variable DC voltage with 6 steps. Look at... (URL) (...) Also not true. The resistance of the motor is not enough to determine the current it will draw (...) (25 years ago, 8-Mar-99, to lugnet.trains)
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Message is in Reply To:
| | Re: Electrical Things (was: Railroad Dilemma)
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| (...) I'm not sure I agree that the voltage is variable. People have reported (via oscilloscope analysis) that it's pulse width modulated 9V instead. This will read on an analog meter like a low voltage, because it's taking the average across time. (...) (25 years ago, 8-Mar-99, to lugnet.trains)
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