Siren motor fire?

[kx250rider]

I own a siren and its a sd10! got it in wisconsin for free but it was hard to ship and this was the siren that cought on fire.

I'm curious as to what happened? My Model 5 threatened to catch fire due to very dirty brushes the first time I tried to give it power. I cleaned the brushes, and no problem.

There's a LOT of current with these motors, so a potential for fire is there.

Charles

(thread split from http://airraidsirens.com/forums/viewtopic.php?t=3678 )

[Robert Gift]

I was wondering the same.

What is there to burn?

The motor wire insulation (shellac) doesn't represent that much fire load, does it?

Unless bees got inside and made wax hives, or birds or squirrels building nests, I don't see what there is to burn.

[Rheems1]

Ohh my, the wire itself will burn very well..... the brushes do burn up as they are made of graphite (on a single phase model) as well. It is very possible to have a siren burn up.... ask the Moosic Fire Department in Pa whose 3T22 caught fire and dumped burning insulation onto the roof of the firehouse and burnt it down.

Dave Fritz

[Robert Gift]

Wow!
How embarrassing.
Bad 3t22, bad 3t22.
But still surprised there is enough.
How does the stuff get out of the motor casing?
Thanks

[Franz?]

The answer is Mouse Wizz.
Mice love sirens almost as much as they love generators. They nest there and the urine accumulates in the nest material.
Mouse urine is as corrosive to insulation as battery acid is to car bodies.

Secondly, motors are insulated with VARNISH, not shelac. The windings are dipped in a tank of varnish after they are inserted into the slots of the stator or rotor and held in by fishpaper. After the windings are connected and tied down with marlin twyne the assembly is dipped for a few hours to get rid of air bubbles, and then baked dry. The varnish provides mechanicle stability for the coil.

[Robert Gift]

Interesting.
Thanks for the information, Franz.
I don't know the difference between varnish and shellac.
The 2t22 motor appears to be well sealed so no animals or insects can nest inside, unless the wire inlet cover is loose or missing.

[JasonC]

A bit off topic, but does anyone have that pic of the fire station on fire with the new model 2 on top about to be consumed? It was posted a few years back on the old board.

[SirenMadness]

Don't I remember seeing that video on The Siren Archive a while after it was posted on the board?

[kx250rider]

VARNISH

All varnish is made from is stale gasoline... No wonder

Also, wayward electricity can become a plasma blast, resembling blue flames. Basically what an arc welder is.

Charles

[3t22]

The answer is Mouse Wizz.
Mice love sirens almost as much as they love generators. They nest there and the urine accumulates in the nest material.

That's what caused the 5 I recorded last April to bite the dust (the sick 5). They brushed off my reports in April that it was in bad health, and sure enough durring August's test all this white smoke came pooring out of it (the planks where it sat is slightly charred directly where the siren was mounted). When they took it down in September, and removed the housing it was crawling with mice. It didn't help that it sat silent for at least 14 years before a very brief period of testing 5 years ago with our old EM director (he was an idiot), than falling silent again until last year when our current EM director wanted to put them back into servnce. He told me all he did was growl it after he repaired the controls. Probably thought "ok it's making a sound, it works fine" . And yes he's sense admitted to me after observing it himself, including the day it burnt up, that he should of listened to me. a WS 2008 now sits in it's spot.