12 VOLT BAYONET BASE LAMP QUESTIONS

Started by JayOcks, May 03, 2010, 11:46:27 AM

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DominicMazoch

The 24 V might have more resistance, but the difference would be so small I don't think it is going to a big difference.

I used a 28 V bulb on an O22 switch, and it seemed to work.  A 14 V bulb runs so hot I was worried it would melt the lantern.

Joe Satnik

Dom,

How did you power your O22 switches?  If constant power, not track power, what was the voltage that you used?

Lee,

Perhaps I should rephrase my previous question on lamp resistance. 

Start with an original lamp. 

If you wanted to design a new lamp that would use the same amount of electrical power, yet be supplied with twice the voltage, how would the resistances of the original ( = Ro ) and new ( = Rn ) lamp filaments compare?

Hint:  Use equation P = V x V/R, 

Hope this helps.

Sincerely,

Joe Satnik
If your loco is too heavy to lift, you'd better be able to ride in, on or behind it.

DominicMazoch

I use about 14 V on the side plug on the switch.

Joe Satnik

Using algebra,

Po = Pn   Original power same as new power.

Po = Vo x Vo/Ro   power is V squared over R

Vn = 2 x Vo  New voltage is twice original

Pn = 2Vo x 2Vo/Rn = Po = Vo x Vo/Ro  substitute

4 x Vo x Vo/Rn = Vo x Vo/Ro  combine twos

4/Rn = 1/Ro   divide out (cancel) Vo squared from both sides

1 x Rn = 4 x Ro  Cross multiply

Rn = 4 x Ro  Drop 1 x (redundant)

So, same electrical power, @ twice the voltage and half the current, the resistance is quadrupled.  (X 4)

Hope this helps. 

Sincerely,

Joe Satnik
If your loco is too heavy to lift, you'd better be able to ride in, on or behind it.

Joe Satnik

Dom,

What are the O22 lamp part numbers, 28 and 14 volt?

Joe Satnik
If your loco is too heavy to lift, you'd better be able to ride in, on or behind it.

DominicMazoch

Right now i am using a Shack bulb.  Only problem is the bulb is taller than the usual O22 bulb.

But Lionel did sell a line of replacement bulbs for 18 volts because of TMCC/L.  That might be a source.

phillyreading

Quote from: Joe Satnik on May 14, 2010, 12:00:39 PM
Using algebra,

Po = Pn   Original power same as new power.

Po = Vo x Vo/Ro   power is V squared over R

Vn = 2 x Vo  New voltage is twice original

Pn = 2Vo x 2Vo/Rn = Po = Vo x Vo/Ro  substitute

4 x Vo x Vo/Rn = Vo x Vo/Ro  combine twos

4/Rn = 1/Ro   divide out (cancel) Vo squared from both sides

1 x Rn = 4 x Ro  Cross multiply

Rn = 4 x Ro  Drop 1 x (redundant)

So, same electrical power, @ twice the voltage and half the current, the resistance is quadrupled.  (X 4)

Hope this helps. 

Sincerely,

Joe Satnik

Joe,

I am totally lost when it comes to algebra! I may know some geometry but that is about it, mainly basic math. Also I think that you are trying to describe an electronic circuit and how it works rather than a basic electric circuit.

Basically when you increase resistance in a circuit you increase the power consumed. So the point that I was trying to get across is that a lower volt light bulb should let you have more power to the motor, this will be noticed with a lower watt transformer.

Lee F.

Joe Satnik

Lee,

You said:

"Basically when you increase resistance in a circuit you increase the power consumed."

No, just the opposite. 

Power = V x V / R

If the Voltage on a load stays the same, and its resistance increases, the power decreases.

/R means "divide by R".

Hope this helps.

Joe Satnik

If your loco is too heavy to lift, you'd better be able to ride in, on or behind it.