Questions about 3 Phase Motors

[Im a Siren Addict3]

Hi

I have some questions about 3 Phase Motors that I hope can be answered. So as some of you know Drumright has 3 2t22A sirens. Last year the motor had to be rebuilt in one of them. Well this year the other 2 just died and at the same time. What I would like to know is what a healthy 2t22A motor looks like and a not so healthy 2t22A motor looks like and One of the 2t22A's was smoking when it was turned on and the other one did nothing why? The one that was smoking was just rebuilt a couple of years ago why would it already be "dead"? The motor that was rebuilt last year cost $2,900 is the city getting ripped off or are we burning up the motor royally?

Thanks!

[FSThunderboltfan1000]

The only reason I can think of why a newly winded 3-phase motor would be smoking is, I'm not a motor expert but, it single phased like the Macon Ga ACA Howler did.

[Jim Z]

The only reason I can think of why a newly winded 3-phase motor would be smoking is, I'm not a motor expert but, it single phased like the Macon Ga ACA Howler did.

The motor can't do anything to destroy itself, but I'm guessing what your talking about is a three phase motor trying to start with one phase missing. Which yeah, can ruin a motor since the armature can't even start spinning.

[Brendan Ahern]

Yes, single phasing will absolutely burn a motor up. This is not the fault of the people rebuilding the sirens. If one of the 3 fuses blows for any reason, you can single phase the motor. Could be a blown fuse, loose wire, dropped a leg of power utility service, a number of reasons. $2900 does seem a little high, but is the company also removing and reinstalling the sirens? The other siren sounds like a break in the windings somewhere, which wouldn't burn it up, just render it useless. It's like cutting a wire between 2 points and wondering why the power went out. Also something I have seen a few times in my line of work is grease getting out of the bearings and smoking the windings that way, either by overheating or contact. I have also seen bearings catch fire, but not on a motor.

[Im a Siren Addict3]

Yes, single phasing will absolutely burn a motor up. This is not the fault of the people rebuilding the sirens. If one of the 3 fuses blows for any reason, you can single phase the motor. Could be a blown fuse, loose wire, dropped a leg of power utility service, a number of reasons. $2900 does seem a little high, but is the company also removing and reinstalling the sirens? The other siren sounds like a break in the windings somewhere, which wouldn't burn it up, just render it useless. It's like cutting a wire between 2 points and wondering why the power went out. Also something I have seen a few times in my line of work is grease getting out of the bearings and smoking the windings that way, either by overheating or contact. I have also seen bearings catch fire, but not on a motor.

Thanks for the info! No we just take it to them and pick it up $2900 is just for repairs.

[Brendan Ahern]

I've never seen a 2T22 taken apart so I could be wrong, but I would imagine it would be labor intensive. I would imagine the whole siren has to be taken apart, the motor disconnected from the rotors and all that. Then when the work is complete, put it all back together and make sure it's all balanced. A lot more work than just rewinding a motor. I've had companies charge of 900-1400 to rewind motors ranging from 25-200 HP, but that was us sending them just the motors off equipment. So for all that is required, that price still doesn't seem bad. And it is still a lot cheaper than new sirens. Are they putting new controls/starters on them?

[Im a Siren Addict3]

I've never seen a 2T22 taken apart so I could be wrong, but I would imagine it would be labor intensive. I would imagine the whole siren has to be taken apart, the motor disconnected from the rotors and all that. Then when the work is complete, put it all back together and make sure it's all balanced. A lot more work than just rewinding a motor. I've had companies charge of 900-1400 to rewind motors ranging from 25-200 HP, but that was us sending them just the motors off equipment. So for all that is required, that price still doesn't seem bad. And it is still a lot cheaper than new sirens. Are they putting new controls/starters on them?

Yep! New pole, new disconnect, new starter, same CD&F radio!