STH-10 Restoration

[OHIO Desperado]

Finally getting back to the restoration of my STH-10.
Single phase unit. Induction repulsion motor design.

Main body. Rather heavy unit.




Horns.. plenty of surface rust. But nothing too bad.
I think they will clean up.



They seem to be cleaning up rather well.



A number of them done. Cleaned up well.


Even the screens weren't too bad. They all turned out like this.




On to the motor and main body.
Brushes were hung in the carriers,, making the siren inoperable. And the reason it was replaced. Commutator was black but was in good shape and cleaned up well. Helps to have a lathe to chuck stuff like this up in to do the work on it. Broke several bolts off in the main motor frame. Will need to drill them out and tap them and make replacement bolts from 3/8" all thread. Bearings are good so not worried about those.

Siren is currently in pieces. Armature is out of the motor frame while I fix the brush carriers and deal with the broken bolts.
More to follow.

[Ohio_Man]

Nicely done! Did you sand/sandblast or use electrolysis for the rust removal on the horns?I'm going to attempt a restoration of a Sterling M10 when this whole pandemic runs out of steam and deer park finishes it's roadwork.

[OHIO Desperado]

Horns, and most all of the exterior were cleaned up with scotchbrite pads on a die grinder.

[OHIO Desperado]

Well, I am back to working on the siren

I got all the broken bolts out of the motor frame.
Forgot to take pictures, but short story is I put the frame in my mill and drilled out the bolts and rethreaded the holes.
There are other pictures of the one half the frame in the mill already.

I got some paint on the motor and the rotor.




The cover band is in poor shape, but I was able to clean it up. Here is a before shot of it.
It got painted red along with the center of the motor (field coil lamination stack).



More to come.
I am going to be looking for another project before long.
I have a little Federal wall mount siren that I am going to put a motor in but after that, I am gonna need another project.

[OHIO Desperado]

Getting to the end of it.

Got the motor back together and the chopper on it.
The brushes were less than fun to get in place, but that's all done too.





One thing to mention here. Spinning your siren with a drill is cool and all, but do remember that if your bottom bolt is safety wired, put the wire back in place before powering it up.
A loose chopper at speed would NOT be good.

20200706_204520[1] by kb8vul, on Flickr

[CanadianTbolt1003]

Nice looks good!

[OHIO Desperado]

Nice looks good!

Thanks... so whats with your STH-10 motor?

[CanadianTbolt1003]

Don't have one. The motor that was on mine was no good and tossed away it was 3 phase on 440V and another voltage I can't remember. this is the form discussion the siren when it was taken down.
The topic on the STH-10 and Sterling 2V8 - https://www.airraidsirens.net/forums/vi ... =2&t=10349
photo of the STH-10 with its motor - https://oi675.photobucket.com/albums/vv ... 0088-1.jpg