shaft movement on Induction motor

[indychuck]

Is the slight forward and aft movement of the shaft a normal movement of this Delco, single phase, 1.5 HP repulsion induction motor?

I just picked it up locally that was on a working air compressor, according to the seller.

I'm going to tear it down for a general cleanup and possible bearing replacement, just curious if I should try to eliminate the movement of the shaft or regard it as normal??

Thank you

Delco 1.5 HP induction on Vimeo

 

[JST]

It's more than usually seen. May be no problem.

The biggest issue is on units with a centrifugal switch, where too much movement in the wrong direction might interfere with the action of the switch.

Your motor is probably a repulsion start induction run motor, which has only a shorting ring, not dependent on shaft position.

You can add washers if it's an issue. But check where the shaft is when running. The magnetic forces will center the shaft somewhere, and that is probably where you should let it run. If you add washers, don't try to force it out of position.

 

[rons]

Is the slight forward and aft movement of the shaft a normal movement of this Delco, single phase, 1.5 HP repulsion induction motor?

I have duplicated internal washers before. Adding a few thou to get some quieter operation. Have to keep opening up the case and trying a new dimension until
the quiet spot is reached. Always good to heat the ends with a torch so that the internal bearing cups don't get scoured from forcing things apart.

 

[Technical Ted]

Some play is required since the armature must find magnetic center in the field windings when running.

Ted

 

[metalmagpie]

That play is normal and should not be monkeyed with. Do not add shims. The rotor must be allowed to seek and find the magnetic center. This is not problematic behavior - all repulsion induction motors are like this.

metalmagpie

 

[Just a Sparky]

This is typical of old repulsion start motors. Lots of play in the thrust bearings so they can find magnetic center.

Bearing replacement is unlikely unless you intend to turn your own - these motors rarely utilized cartridge ball bearings. Usually only seen in vertical motors or as an up-charge for some special application with substantial thrust loads. Shaft play indicates yours has the usual bronze bearings.

AFAIK Wagner mostly made brush lifting RSIR motors rather than R-I. Type RS generally denotes a brush lifting RSIR, type RA usually a brush-riding RSIR... I forget the type code for straight R-I motors.

 

[Strostkovy]

I've dealt with a motor nearing end of life by putting a spacer between the pulley and the bearing to stop the rotor from wandering and switching the start caps on while running.

 

[Just a Sparky]

As long as the motor was oiled on a regular basis and taken apart for cleaning & brush/commutator inspection once in a while, it should run pretty much forever. These old repulsion start motors were often built like tanks, usually with either yarn- or ring-fed circulating-type bearings. Simple, messy systems of lubrication - but also very thorough and effective ones. Much more skookum than the plain "oiless" impregnated-bronze sleeve bearings seen today as long as they get an oil change once in a while. Wagner, Delco, LeLand, Century, Master, etc. all made very solid, chunky repulsion start motors.