> Posted by: "Wallace Collins" [EMAIL PROTECTED] wcollins2_99
> Date: Sat Jan 13, 2007 8:12 pm ((PST))
>
><cut> I have a bunch of steam engines fitted with CL-011-01
>(forward0 or CL-012-01 (forward reverse) constant light units. I
>recently got from Dave Fontana a rebuilt brass caboose (another
>story) that he fitted with two beautiful scale size brass marker
>lights which were drilled out to hold Miniatronics Model 18-CO3-10
>Incandescent lamps (1.5 volt 30mA 1.2mm diameter). Dave hooked up
>two in the marker lights to the CL-011-01 unit, with a third
>lighting the interior. When I first put it on the track they all lit
>but I was afraid they were too bright. Sure enough, the next time I
>ran it they were all out. I have a supply of those lamps so I
>replaced them. This time they just went PUFF. I spoke to the lady in
>Customer Service and she informed me with disgust that these Units
>were designed to be hooked up in series with the engine's motor, not
>directly to track power and with a five volt output they would
>certainly burn out a 1.5 volt rated lamp.
>
>Here is where I asked for but didn't get help. I had been told
>before, I am sure by someone at Miniatronics, that they could be
>used in a caboose by putting a resister in series with the Unit.
>This seemed logical since all the motor did was put resistance in
>the circuit.
>
><snip> What resistance should I put in series with the Unit to
>replace the missing motor? <bobbit>
If the output of the unit is 5 volts and you need 1.5 to light your
.030 amp bulbs wired parallel, then you need a (5 - 1.5) / .030
resistor for each. This works out to about 117 ohms. The nearest
standard resistor value is 120-ohm.
The other thing you need is the wattage of the resistor. Power
dissipation in watts is equal to the square of the voltage dropped
across the resistor divided by the resistance or 3.5 * 3.5 / 120 or
0.1021. The nearest value, I believe, is 1/4-watt.
Therefore, based on what you've written, I'd say you need three
120-ohm, 1/4-watt resistors for the bulbs in your caboose. Perhaps
somebody else can confirm or correct my calculations.
I see that Radio Shack has 150-ohm resistors, which should be
suitable. They come in packs of 5 for 99 cents.
--
Bill Roberts
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/S-Scale/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/S-Scale/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:[EMAIL PROTECTED]
mailto:[EMAIL PROTECTED]
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
