RailPro > RailPro Specific Help & Discussion

Lights causing LM-3S to overheat?

<< < (3/3)

gregeusa:
Thanks... based on that, the OP could set the brightness way down on all the lights and convince himself that it's the lamps drawing too much.

Also perhaps the lower brightness would stop the system from overheating.

Lastly, perhaps the lowered brightness might be acceptable.

Greg

CPRail:
Sorry guys, between needing to clear a couple of recent snowfalls, a second emergency vet visit (dog is doing better now) and a very convoluted trip to get my mom to the airport, this past week/weekend has been exhausting. As such I've done ZERO railroading  :(

To top it off, now I've got some kind of bug.

Once I'm back in action, I'll crack the unit open again and check those connections and the other things mentioned.

Stay tuned.

CPRail:
Howdy! Finally had time to crack open the SD45T-2 on the weekend. Attached is a picture of the board -  no cross over between the blue and white wire as asked by Tim.

I checked the output on the gyralite connections - it wavers up and down, peaking at 1.13 volts and down to about 0.15 volts as it cycles. The headlights sit at 1.27 volts.

I put it on a rolling road and ran it at about 30% throttle with sound and lights on for about 30-45 minutes, with the shell off. It rose in temp, but sat in the operating zone. For comparison purposes, I also ran a Genesis GP9 with the lights turned on on both ends, beacon on and sound on at the same time - but shell on. The bulbs are not at full intensity as Greg was wondering.

Is this just a LM that doesn't like being in the confines of a hood unit and should be relegated to a carbody unit so it can breathe? It's location is right above the motor, but it is under the open dynamic brake fans, so there is venting but not all around.

Or do I just bite the bullet, pull the bulbs and put in LEDs?

gregeusa:
Sure seems like LEDs the most straightforward option.

small lights can draw a lot of current, and using Ohms law V=IR, for a given wattage of bulb, and the voltage goes down, the current goes up.

So, unless the "common" voltage is pretty low, you could have some current in the lamps, almost equaling the motor!

No one offered what the "common" for lights is, but I would guess it is rectified track/input voltage, about the worst case situation for 1.5 v bulbs.

Greg

Update: I cannot find a "manual", but the 2 page "instruction sheet" shows and implies that the common for lights is rectified track power, so 1.5 volt incandescent lamps should really not be connected without a resistor, even though that is a poor way to limit current in this case.

The Dimming feature uses PWM to reduce the AVERAGE current, but full voltage "spikes" would be applied to the 1.5 volt bulbs, and that could indeed cause overheating. Just reducing the "brightness" may still overload the system.

In absence of any specs on max current per output, and max total lighting current, one can only guess, or see if you get overheating, as you are experiencing.

put in the LEDs with appropriate dropping resistors my best recommendation..

Navigation

[0] Message Index

[*] Previous page