Smoke unit Ohms?

If it has resistance it is not a short. Heat generated would depend on voltage input and how it is regulated (if it is at all). The 8 ohm one would allow a little over a 2 amp draw at track voltage of 18 or about 35 watts. A 4 ohm one twice that. If running off directly off AC track voltage install a 3 amp diode in series to the unit,that would cut draw in half.  If run off a regulated supply replacing the 8 ohm one with a 4 ohm one would not be a good idea  unless voltage is cut further some how.

In general wire wound resistors fail open,so if they have resistance and continuity they are good.. I have not messed with smoke units much so perhaps others have insight.

Dale H

 Dale, I tried to respond earlier just as we went off line!

 The smoke unit is going through the PS2 board for control. I'm not sure of how it's handled by the board.

 Ray emailed me and now I'm going to give it a try.

I need to figure out the resistor value to hook up LED's as headlights. I think the board's output runs at 6 volts for the lights.

I'm off to look at your threads once more:

http://www.jcstudiosinc.com/BlogShowThread?id=407&categoryId=

Please keep these posts. I always use them as ref. In G we draw more amps per engine. I would then need Higher amp value chokes than the ones used in O??

Sheesh. I went a couple hours without the forum it's like having withdrawls!!!

Joe

I would only use the  same value smoke coil if driven off the board.  Putting one in with a lower resistance could damage the board.

For the headlamp replacement with an LED 150 ohm or more,1/4 watt should work.The LED needs to be in proper polarity. To calculate use Ohms law. 6 volts in minus a 3 volt drop divided by .02 amps (the draw of most LEDs) equals 150 ohms

Here is a headlamp circuit,you only need the resistor and LED if powered of the PS2 board.

www.jcstudiosinc.com/BlogShowT...=619&categoryId=

The choke values shown are half amp in the LED thread you linked and are for passenger cars. In O gauge engines you can usually get away with a 4 amp choke.

Dale H

The USA Trains smoke unit was designed to be used with their little regulator board that actually controls the voltage to the smoke elements and provided DC for the fan.  It's simple to swap those resistors out for higher value ones for use in your environment.  The USA Trains smoke units I've purchased have a single resistor and the fan, no other components of any kind on the board.

Joe, Hook up the 4 ohm smoke unit as it'll do no harm to the PS2 smoke circuit. MTH One Gauge smoke units come with 3 elements @ 4.5 ohms and I add a fourth to bring it down to 4 ohms or less.

When upgrading a Turbine the directions state to tie 2 smoke units together or 4 heating elements.

The Hexfet that powers the smoke unit heaters is rated 55v 3.8 amps so you ain't gonna hurt it.

 Some interesting stuff. Thanks all!

Joe,  Chuck was right, forgot about the upgraded FET for 2 smoke unit operations.  The 3 16 ohm 3W resistors in the MTH smoke do give about 5.3 ohms.  You just need to make sure the USA smoke unit has higher watt rating elements.  The board will handle it. G