My Model 5 again

[pyramid head]

This time in attack for a short 3 cycles, my Model 5 roars in the back of my pickup. I want some opinions on this, towards the end of the video a sound can be heard coming from the motor. I really have concern for this, and I am willing to bet it is not siren friendly. If the verdict is bad, I will have to re-tap the rotor holes to pull the rotor.
http://www.youtube.com/watch?v=r1vbM5K9nNY

[Corey Hudson]

I cannot really tell what is wrong, the youtube video is too compressed. If you put the audio on putfile or something i can give it a check.

[Archon]

Is it single phase? if it is could be the brushes you are hearing.

[murrfarms]

Is it single phase? if it is could be the brushes you are hearing.

Yes, his is single-phase. None the less, it sounds great!

[ver tum]

I do hear some motor noise towards the end of the wind-down, but I've heard other sirens that were noisier than this one. I can hear a very similar noise sometimes on one of my electric fans, but the fan runs fine. Some motor oil couldn't hurt though.

[Mr. Machine]

If you slide the Play cursor back and forth between 0:10 and 0:40, you can see the siren rotate in place.

[ver tum]

If you slide the Play cursor back and forth between 0:10 and 0:40, you can see the siren rotate in place.

That could explain the noise. The siren may not be sitting completely level in the back of that truck. I've noticed that if some electric motors are even slightly unlevel, they can make that sound.

[pyramid head]

I am afraid it is not as simple as the unit sliding in the bed of my truck. I can hear a very distinct clicking sound from it. A brush is what I was thinking, but why would it click like that? I have spun a few brushed motors before and they do not really click like that.

[JasonC]

All of my model 2's have made that noise. I think mine was in the bearings, although it could be the brushes in yours. You have a 40+ year old giant piece of metal spinning a close tolerances, its going to make some noise of some sort (and of course you still haven't refurbished the inside yet)

[holler]

I am afraid it is not as simple as the unit sliding in the bed of my truck. I can hear a very distinct clicking sound from it. A brush is what I was thinking, but why would it click like that? I have spun a few brushed motors before and they do not really click like that.

Both of the motors in my Model A's click if you turn them by hand.

I think you are worrying too much, the siren sounds fine. Anything that old is not going to be smooth as silk.