Electrical Engineering - The rotor shaft is loose as a goose.

Author

The rotor shaft is loose as a goose.

spokes

2007-02-12, 5:25 pm

I have this induction motor, the rotor shaft is attached to the rotor
core with an interference fit, the shaft is cooled and the core is
heated and then they are pressed together. My problem is that this fit
sucks and the shaft is rotating freely inside the core.

Does anybody know of any nationally recognized companies that
specialize in making/fixing rotors.

Thanks in advance.

BFoelsch

2007-02-12, 5:25 pm

"spokes" <blairlakehead_@hotmail.com> wrote in message
news:1171315572.508038.149920@m58g2000cwm.googlegroups.com...
> I have this induction motor, the rotor shaft is attached to the rotor
> core with an interference fit, the shaft is cooled and the core is
> heated and then they are pressed together. My problem is that this fit
> sucks and the shaft is rotating freely inside the core.
>
> Does anybody know of any nationally recognized companies that
> specialize in making/fixing rotors.
>
> Thanks in advance.

Strange - usually there is a key/keyway involved.

Any GOOD motor shop should be able to repair it, but having a new rotor
made, except by the OEM, is probably out of the question.

Where are you located? What are the details of the motor? Size, RPM, etc.
>

**THE-RFI-EMI-GUY**

2007-02-12, 8:25 pm

Try some Loctite or epoxy the thing together.

spokes wrote:

>I have this induction motor, the rotor shaft is attached to the rotor
>core with an interference fit, the shaft is cooled and the core is
>heated and then they are pressed together. My problem is that this fit
>sucks and the shaft is rotating freely inside the core.
>
>Does anybody know of any nationally recognized companies that
>specialize in making/fixing rotors.
>
>Thanks in advance.
>
>
>

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

2007-02-13, 9:25 am

In article <1171315572.508038.149920@m58g2000cwm.googlegroups.com>,
"spokes" <blairlakehead_@hotmail.com> wrote:

> I have this induction motor, the rotor shaft is attached to the rotor
> core with an interference fit, the shaft is cooled and the core is
> heated and then they are pressed together. My problem is that this fit
> sucks and the shaft is rotating freely inside the core.
>
> Does anybody know of any nationally recognized companies that
> specialize in making/fixing rotors.
>
> Thanks in advance.
>

Easy. I've done this with similar problems. Remove the shaft. Place the
part of it that fits into the rotor into a vise. Squeeze it just a bit
to make it slightly oval. Then press it back into the rotor. Be careful
you don't bend the shaft or unbalance it.

Al

spokes

2007-02-13, 5:25 pm

On Feb 12, 6:15 pm, "BFoelsch" <BFoel...@comcast.ditch.this.net>
wrote:
> "spokes" <blairlakehe...@hotmail.com> wrote in message
>
> news:1171315572.508038.149920@m58g2000cwm.googlegroups.com...
>
>
>
>
> Strange - usually there is a key/keyway involved.
>
> Any GOOD motor shop should be able to repair it, but having a new rotor
> made, except by the OEM, is probably out of the question.
>
> Where are you located? What are the details of the motor? Size, RPM, etc.
>
>
I'm in Ontario Canada, the motor is kind of unusual I think. It's a
two-phase squirrel cage induction motor. One phase is a ref. phase and
the other is control. The rotor is only 3 =BD" long by 2 =BD" round. I'm
going to go back to the manufacture and get them build some new ones
that don't come loose. Thanks for the help everybody - the loctite
idea was used and may have worked. However I need something that meets
the original design. That's why I can put it in a vice and squeeze the
crap out of it.

Thanks again.

BFoelsch

2007-02-13, 5:25 pm

"spokes" <blairlakehead_@hotmail.com> wrote in message
news:1171395813.525673.120570@j27g2000cwj.googlegroups.com...
On Feb 12, 6:15 pm, "BFoelsch" <BFoel...@comcast.ditch.this.net>
wrote:
> "spokes" <blairlakehe...@hotmail.com> wrote in message
>
> news:1171315572.508038.149920@m58g2000cwm.googlegroups.com...
>
>
>
>
> Strange - usually there is a key/keyway involved.
>
> Any GOOD motor shop should be able to repair it, but having a new rotor
> made, except by the OEM, is probably out of the question.
>
> Where are you located? What are the details of the motor? Size, RPM, etc.
>
>
I'm in Ontario Canada, the motor is kind of unusual I think. It's a
two-phase squirrel cage induction motor. One phase is a ref. phase and
the other is control. The rotor is only 3 ½" long by 2 ½" round. I'm
going to go back to the manufacture and get them build some new ones
that don't come loose. Thanks for the help everybody - the loctite
idea was used and may have worked. However I need something that meets
the original design. That's why I can put it in a vice and squeeze the
crap out of it.

Thanks again.

Ahhh, a tiny motor. I was thinking more along the lines of a standard
industrial motor.

What is it for, some type of instrumentation application? The two phase
thing was extremely popular with chart recorder manufacturers 40 years ago,
and I am curious to know what niche that design would fill today.

Thanks in advance.

spokes

2007-02-13, 5:25 pm

On Feb 13, 4:34 pm, "BFoelsch" <BFoel...@comcast.ditch.this.net>
wrote:
> "spokes" <blairlakehe...@hotmail.com> wrote in message
>
> news:1171395813.525673.120570@j27g2000cwj.googlegroups.com...
> On Feb 12, 6:15 pm, "BFoelsch" <BFoel...@comcast.ditch.this.net>
> wrote:
>
>
>
>
>
>
>
>
>
>
c=2E[color=darkred]
>
> I'm in Ontario Canada, the motor is kind of unusual I think. It's a
> two-phase squirrel cage induction motor. One phase is a ref. phase and
> the other is control. The rotor is only 3 =BD" long by 2 =BD" round. I'm
> going to go back to the manufacture and get them build some new ones
> that don't come loose. Thanks for the help everybody - the loctite
> idea was used and may have worked. However I need something that meets
> the original design. That's why I can put it in a vice and squeeze the
> crap out of it.
>
> Thanks again.
>
> Ahhh, a tiny motor. I was thinking more along the lines of a standard
> industrial motor.
>
> What is it for, some type of instrumentation application? The two phase
> thing was extremely popular with chart recorder manufacturers 40 years ag=
o,
> and I am curious to know what niche that design would fill today.
>
Lets just say it's really old (50 years) technology.

Don Kelly

2007-02-13, 8:25 pm

"BFoelsch" <BFoelsch@comcast.ditch.this.net> wrote in message
news:z6adndkyrqAVsk_YnZ2dnUVZ_oytnZ2d@giganews.com...
>
> "spokes" <blairlakehead_@hotmail.com> wrote in message
> news:1171395813.525673.120570@j27g2000cwj.googlegroups.com...
> On Feb 12, 6:15 pm, "BFoelsch" <BFoel...@comcast.ditch.this.net>
> wrote:
> I'm in Ontario Canada, the motor is kind of unusual I think. It's a
> two-phase squirrel cage induction motor. One phase is a ref. phase and
> the other is control. The rotor is only 3 ½" long by 2 ½" round. I'm
> going to go back to the manufacture and get them build some new ones
> that don't come loose. Thanks for the help everybody - the loctite
> idea was used and may have worked. However I need something that meets
> the original design. That's why I can put it in a vice and squeeze the
> crap out of it.
>
> Thanks again.
>
>
> Ahhh, a tiny motor. I was thinking more along the lines of a standard
> industrial motor.
>
> What is it for, some type of instrumentation application? The two phase
> thing was extremely popular with chart recorder manufacturers 40 years
> ago,
> and I am curious to know what niche that design would fill today.
>
> Thanks in advance.
>

-----------
It's a servo motor-- used in control systems for positioning. Steppers now
do the job. It is probably cheaper and better to simply go to a stepper
motor.
--

Don Kelly dhky@shawcross.ca
remove the X to answer
----------------------------

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