RE: Disintegrating squirrel cages ?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "David Dean by way of Terry Fritz <twftesla-at-uswest-dot-net>" <deano-at-corridor-dot-net>

Hi Ritchie,

I would not worry about it at all. The rotors I have cut into show no
evidence of anything possibly coming loose. I believe the aluminum goes all
the way around the iron so as to be in one piece.

later

deano

> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Tuesday, February 20, 2001 5:51 PM
> To: tesla-at-pupman-dot-com
> Subject: Disintegrating squirrel cages ?
>
>
> Original poster: "R.E.Burnett by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <R.E.Burnett-at-newcastle.ac.uk>
>
>
> Hi Guys,
>
> Given that the procedure of modifying induction motors by grinding
> flats seems quite common on this list,   I wondered if anyone has
> experienced problems with the squirrel cage rotor breaking-up
> at speed ?
>
> I have modified a number of small induction motors for synchronous
> operation in the past,  and the depth of the flats has always meant
> that some of the aluminum shorting-bars of the rotor became exposed.
>
> I had not given much thought to this until it was brought to my
> attention today by a man who is milling flats on a 1.5 HP 3000RPM
> motor for me.  He was concerned that aluminum which is no longer
> covered by the iron laminations could foul the stator due to
> "centrifugal force" when the motor is run at speed ?
>
> This is a hazard that I had not thought about,  but will stop worrying
> if nobody has experienced any problems.  I guess the rotor is quite
> small,  and 3000RPM isn't really that fast,  but I would be interested
> to hear other peoples thoughts / experiences about this.
>
> 							Cheers,
>
> 							-Richie,
>
>
>