As we have mentioned, our current priority is fixing the headlight resistor system in the 319. After some effort, I decided that trying to patch up defective resistors wasn't going to work, so the next step is to remove them and try using new resistors of an improved design. As a philosophical principle, we try to use original fabric whenever possible, but when it comes to high-voltage electrical systems, we have to be practical. If the headlight resistors fail, operating at night is futile. Or at least dangerous and illegal.
After removing the front plate and all of the old wire-wound resistors, the box looks like this:
You shall, of course, observe that the back plate has a large hole rusted out of it. That improves the air circulation, I suppose, but it can be eventually fixed by tack welding. (That's far outside my skill set, but we have plenty of people with the necessary expertise.) And I took measurements so that new resistors can be attached to a separate metal plate and then inserted into the circuit.
The front panel was in better shape, so I cleaned it up, and repainted it in the shop.
Meanwhile, I haven't seen most of the regulars for a week or two, but they're continuing on their tasks. Here we see a part of the progress on the 306.
I spent part of the day in a meeting, more about that later.
Finally, the 749 was providing revenue service.
The crew were Gregg Wolfersheim and Jeff Fryman.
I wish now I had thought of recreating this scene from 50 years ago a little better:
Same motorman, same railroad, different car. And as a matter of fact, Gregg has held up a lot better than the 154.
Randall, last year I spotted your 2018 discussion of Westinghouse HL resistors on RYPN. Now you need some headlight resistors. What I never got around to posting is that rated volts times rated volts divided by watts equals ohms. I took the catalogues for the suggested Tempco brand mica and channel style strip heaters, ran them through a spreadsheet to get the ohms and then sorted it by terminal type. There seemed to be several that would fit the HL case and preserve the look. There are also several that may fit the headlight circuit and fit the box even if they don't have the same look. These are rather pricey but may solve your needs. A few alternatives come from the fact that two 40 ohm 400 watt resistors wired in series (80 ohms) are the same as two 160 ohm 400 watt resistors wired in parallel (80 ohms). If you could describe the needed headlight circuit resistances a bit more maybe we can work something out.
ReplyDeleteBill West
Thanks, Bill. We know how to do the calculations. And I posted all of the electrical information you need back on July 28. Now the box has interior dimensions, allowing for some clearance, of approximately 16" horizontal, 12" vertical, and a depth of 3 to 3.5", although I think that could be increased by mounting the front plate out from the box. But it strikes me that two of the tubes, 80 ohms of resistance, are only used on dim and therefore are dissipating only 300W each. That might give us a little more room.
ReplyDeleteI believe that EMD generator field shunt resistors would fit and give you what you need. Time to raid the diesels!
ReplyDeleteRandy
So, a week later, can you tell us the outcome of that meeting? Curious minds want to know...
ReplyDeleteO. Anderson
I suppose they do. A series of meetings was held to discuss various aspects of the Museum's organization, but I don't want to be more specific until I get an official description for public release. There hasn't been any outcome yet.
ReplyDelete