When I have nothing running on my postwar tubular track I have about 19V from my KW as measured at the track.
When I put a 736 locomotive and passenger cars on it I get a maximum of about 14.5 V. This is using just one of the track outputs, with nothing else using any power.
Is this normal or is the transformer not performing correctly?
Replies sorted oldest to newest
That is correct. The voltage will drop as you add to the load. The KW has a continuous rated output of about 140 watts, with a steamer(e-unit, motor, smoke element, headlamp, whistle relay) and passenger cars it adds up quickly. Figure 3-4 watts per bulb tor the passenger cars, each pair of switches has 3-4 bulbs as well depending on type.
Thanks Rob,
I had 6 2500 series cars ,so lots of bulbs.
I assume a ZW would have less voltage drop.
I have one sitting around, just need to test it and get it running
Hi that's why many people switch over to Led's in passenger's cars Led's only draw about 20 MA each as opposed. to much more current draw!
Alan
The variable outputs of the KW have quite a bit of sag, but the fixed "20V" output is much better. Still, I wouldn't replace any of my Powerhouse 180s with my KW.
@Alan Mancus posted:Hi that's why many people switch over to Led's in passenger's cars Led's only draw about 20 MA each as opposed. to much more current draw!
Alan
Actually, if you use the strips and a regulator, the total car with anywhere from 18 to 30 individual LED's will end up using maybe 30ma for the whole car for nice intensity. 
Yes, I confirm a lot of voltage sag.
Thanks for the info on LEDs. I assume if I'm replacing with LEDs I should add capacitors.
But first I going to try my ZW
I'm here to tell ya.....LED light strips and @gunrunnerjohn's regulator boards are the magic potion for this problem. The cars are evenly lit and do not flicker. And power draw is nil!
I mounted my regulator boards on little plastic "stand-ups" and align them so that the potentiometer is visible through the passenger car's door window. That way I can adjust the brightness using a jeweler's screwdriver through the window.
Good idea on the mounting, Thanks.
If you're running strictly conventional, I'm working on a new board that will work over all voltage ranges.
Very nice work John!
Unless you are using a humongous transformer, you will see a drop of voltage under load regardless of the type of toy transformer (KW, ZW, K-Line 400 Watt, etc.) It's the way physics works.
Access to this requires an OGR Forum Supporting Membership
