Thunderbolt 1003A, Madelia, Minnesota

[falconhawk]

I was thinking the exact same thing.

[Tyler]

That's a pretty nifty little box they got the AF timer in.

Yeah and a huge screw lock they've got there.

[Andys Live WX]

Does anyone know why this Thunderbolt sounds like it is connected to T1 on the transformer when it is actually connected to T5? It has sounded like this since I was born, so has there been something wrong with this transformer for such a long period of time?

[holler]

Check the output of the transformer and see what you get. Could be the transformer, chopper motor problem, or a parts mismatch.

Always start with the voltage though. If you get 120 on tap 5 something is definitely wrong.

[Andys Live WX]

I forgot to look at how the incoming lines from the chopper motor starter are connected to see if it is connected wrong to the transformer. Voltage drop from the blower running shouldn't be an issue either, since those look like adequately sized conductors. As long as it works, and because it has worked this way for years, I'm going to leave it until the city approves to go ahead with the project, unless problems occur.

[Andys Live WX]

I was up there with another local electrician today and found out this Thunderbolt was made in January of 1970 according to the date on the solenoid flasher. I tested the flasher in the fast position and it does not spin. The solenoids engage alternately when spun manually, but it will not spin on its own. I took a reading across taps C and 5 on the transformer with the chopper motor starter closed. I measured 200 volts. So I'm guessing the chopper motor is half toasted. I listened to the chopper coast down when I manually tested it and concluded it will definitely need bearings if and when it comes down. They are not tight, but they sound like a salt shaker.

[Mark N]

Do you think it's coming down anytime soon? And if Madelia needs bearings for it, the part number is either 87502 or 6202, depending on size (https://airraidsirens.com/forums/viewto ... f=2&t=8247).

[Andys Live WX]

This city has to approve the bids for all the work before we can take it down. Bearings will hold up for a while since it only runs a couple minutes each month.

[Andys Live WX]

Just thought I'd update the forum on this topic since it has sat dormant for a while. Madelia tabled the Thunderbolt project until this coming fall because the council was worried about it not being in service if there were a weather warning. I did make sure they were aware that there is a problem with the chopper motor and that it should be looked at soon. But I did think of something while this topic sat. If you look at the picture of the RCM1, notice the size of the blue conductors for the chopper motor. They appear to be only #14, but for the length of wire all the way up to the chopper, wouldn't you think you would want to bump up a size because of voltage drop? That could be why the chopper motor is running slow on tap 5 because if you took a volt meter and measured it at the chopper motor it could be only 120v. I measured 200v at the transformer on tap 5. Now I would of thought the electricians who installed it back then would of known better than this. What do you guys think?

[CDV777-1]

It doesn't look to me like it's more than 20 feet to the chopper motor from the RCM in that pic so I don't see how it would be a long enough run to matter.
It's been a while since I measured current to a chopper on a thunderbolt but if I remember correctly it's not more than 6 amps. Rating for 14ga wire is 15.