Not being a motor person, is it alright to remove a motors rotor and reinstall it turned end for end. We had a motor come in today, where the connections were opposite the old motor. So we pulled rotor turned it 180 deg and reinstalled. Just curious it ran well when started.

If there is a problem with rotor rotation, the normal easy solution would of course be to swap any two leads.

Apparently that was not an acceptable solution for you guys?

The other solution that it sounds like you guys did was as follows: Remove endbells and rotor, reverse the rotor, reinstall outboard endbell on what used to be the inboard end and vice versa. If stator is in the plant you also would need to turn the stator around at this point to keep the shaft extension on the proper end.

I don't see any reason why it wouldn't work as long as:
- the end-bells are interchangeable
- the new location of the terminal box is acceptable (it will be opposite it's previous location which could create a problem if there is not enough slack in power cables to reach the new location).
- there is not a reversal of direction of a rotor with unidirectional fan. Shouldn't be a problem as long as rotor is same direction as original manufacture.
- I assume we're talking about horizontal motor. The vertical motor stator frame may not be symmetric top for bottom.

But again swapping leads would be a helluva lot easier.

This message has been edited. Last edited by: electricpete,

thanks for the responce pete. It was actually not a rotation problem. I know with rotation you just swap two leads. This was a case where the "peckerhead" was opposite the old motor and we didn't have enough flex in the existing wiring to hook it up like it was. That's why they turned the rotor 180 deg. Motor seemed to run fine when started up. I was just curious as to whether the rotor and stator are installed in a paticular arraingment to each other and if it is good or common practice to mess with this arraingment. I've never seen or heard of it being done before.

This is a common action referred to as changing F2-F1 (connection box side in relation to opposite shaft end) and is performed by motor vendors and repair shops quite a bit.

The key to success is that the rotor sits centered in the stator core. The way to verify that it is correct is to place one endshield on the motor and replace the rotor. Check to make sure that the edge of the rotor laminations are close to the edge of the stator core laminations before installing the other endshield.

Howard

Thanks Dr. Penrose. I don't think anyone did the checks you refer to (I wasn't involved with that part just the reinstallation in the field) but will definitely keep that in mind should this come up again.
Kind regards,