AO Smith 1 & 1/8 HP Motor Guide - Forward / Reverse, Bearings, Wiring, etc.

[joshh]

I'm looking forward to seeing a picture of the reverse switch location.

The photo album has a few pictures not yet posted here yet, this will give you a sneak peek at the mounting location

[freedomlives]

I have this same A. O. Smith motor. I have just gotten it over to Slovakia where I live, having shipped it two months ago from my mother's garage where its sat several years since I moved over here.

I read that the motor can be converted to run on 220V, and had hoped that it would be just a jumper I needed to change inside the motor. Obviously its not!

To round out this excellent thread on wiring of the motor, could someone clarify what connections need to be made to get 220V?

I am guessing that I would connect one of the run wires connected to the white wire and the blue wire together, and the other two run wires would go one each to hot and neutral of the supply. Is this correct?

And what then to do about the starting coil with its 120V capacitor? I can get other capacitors without too much problem here, and I suppose changing the value of the capacitor could be calculated to change the reactance in such a way as to limit current and prevent over heating in the start coil? Or I have read that MOVs could be used to limit current and even take the place of the mechanical switch. How long is the starting coil energized, and how much current flows through it?

Also, if the specific bearings needeI have this same A. O. Smith motor. I have just gotten it over to Slovakia where I live, having shipped it two months ago from my mother's garage where its sat several years since I moved over here.

I read that the motor can be converted to run on 220V, and had hoped that it would be just a jumper I needed to change inside the motor. Obviously its not!

Were either of the bearings for this motor having inch ID instead of metric?

Thanks,

Andrew Ray

[JPG]

There are two 'run' windings. For a 230v connection, the two run windings would need to be connected in series. Polarity is critical. They must not 'oppose each other'.

Thus ignoring the start circuit wires for a moment, there are two run winding wires connected to each 'input wire'. two to the white, and two to the blue. The two run windings must be identified(which run winding wire that was connected to the white wire is connected to the blue wire on the other end).

For 230v connection a run winding wire initially connected to the white wire must be connected to the other run winding wire that was originally connected to the blue wire. The remaining run winding wires are then reconnected to the blue and white wires which externally are connected to a 230v source.

Hopefully this will help!

Label the two run winding wires originally connected to the white wire A and B.

Then determine which of the two wires originally connected to the blue wire provides continuity to the A wire. Label that wire A'. A and A' are opposite ends of one run winding.

The remaining run winding wire originally connected to the blue wire should provide continuity to B. Label that wire B'. B and B' are opposite ends of the second run winding.

Internally(or externally if desired) connect A' to B. Reconnect A to the white wire, and B' to the blue wire.

Now the start circuit, it is connected as original, but across one of the run windings. The series run winding connection acts as a voltage divider providing half voltage to the start circuit.

A word of caution. I assume you have a 50 Hz power source. A motor designed for 60 Hz operation will run hotter when running on 50 Hz. Also it will run slower by a 5/6 factor.

[freedomlives]

I got it rewired, and replaced the bearings. Unfortunately, I took it to a motor shop to have new bearings put on, and when I got home realized that one of the bearings needs to come off for that screw on retainer. So the motor shop put on 6203-2RS bearings, and since I damaged the seal taking off the bearing, it now has one 6203-2ZR C3 bearing, both ZVL brand (Made in Slovakia).

However, the thing is quite noisy-- 79dB according to the phone app I used, compared to 20dB without the motor running. I certainly hear a lot more noise than just the fan, and this is with the motor on its mounting tray but sitting off of the rest of the shopsmith (propped up with bags of new diapers which we have around for our son) and with the fan sheave on.

I can't compare really well how the noise is now vs. before-- while in the U.S. this winter I used it just briefly, and before three years ago when I was doing a lot of turning, but I can't remember how it sounded.

Should I replace the other 6203-2RS bearing with a 6203-2ZR C3? Is using a C3 bearing adding to the amount of vibration? Could it be that running the motor on 50Hz just leads to more vibrations?

I suppose also that the bearings themselves just might not be the quietest in the world. I suppose that as I paid just 1€/bearing ($1.30) I might just be getting what I paid for...

[JPG]

I got it rewired, and replaced the bearings. Unfortunately, I took it to a motor shop to have new bearings put on, and when I got home realized that one of the bearings needs to come off for that screw on retainer. So the motor shop put on 6203-2RS bearings, and since I damaged the seal taking off the bearing, it now has one 6203-2ZR C3 bearing, both ZVL brand (Made in Slovakia).

However, the thing is quite noisy-- 79dB according to the phone app I used, compared to 20dB without the motor running. I certainly hear a lot more noise than just the fan, and this is with the motor on its mounting tray but sitting off of the rest of the shopsmith (propped up with bags of new diapers which we have around for our son) and with the fan sheave on.

I can't compare really well how the noise is now vs. before-- while in the U.S. this winter I used it just briefly, and before three years ago when I was doing a lot of turning, but I can't remember how it sounded.

Should I replace the other 6203-2RS bearing with a 6203-2ZR C3? Is using a C3 bearing adding to the amount of vibration? Could it be that running the motor on 50Hz just leads to more vibrations?

I suppose also that the bearings themselves just might not be the quietest in the world. I suppose that as I paid just 1€/bearing ($1.30) I might just be getting what I paid for...

A motor needs a C3 bearing due to the heat range.

Noise aside, how 'smooth' does manually rotating it feel?

[freedomlives]

It feels smooth to me, no sort of "play" that I can feel.

I wonder why the motor shop didn't use C3 bearings?

Should I change out the the non-C3 bearing then?

I took photos of the rewiring I did for 240 volts, they are here:
Rewiring Photo Album

They aren't, however, annotated. I'll get to that.

[joshh]

If you feel like trying to get the motor quiet, you might try taking off the motor spring and the floating sheave. Run the motor with just the fan sheave and take your sound reading. I was getting up to 20 decibels or so of added noise from the spring and the alignment of the sheaves. The decibel reading I took was with the motor facing up and sitting on top of my workbench.


Edit: I read your post more thoroughly and didn't notice you did this already. I think it may just be that the bearings are noisier but not necessarily bad. The NTN bearings I used were about $20 each from grainger.

[joshh]

I did some digging at the NTN and NSK websites and other bearing websites. They all agree with JPG and said when in doubt always use a c3 bearing in electric motors BUT also said many motors are being made with "normal" bearing internal clearance (which is between c2 and c3). They also said some are made with CM clearances which are tighter than c3 and cn. The bearings I pulled out were not c3 bearings and I know they were original.

On a side note, a c3 bearing will have more noise and vibration that a cn bearing.

[charlese]

Not motors, but your pix with the curtains reminded me of the days we repaired snowmobile engines on a kitchen counter. Takes an understanding wife! No?

[freedomlives]

The bearings I pulled out were not c3 bearings and I know they were original.

On a side note, a c3 bearing will have more noise and vibration that a cn bearing.

joshh--

What brand and clearance of bearings did you use on the motor to get the noise levels that you showed? Because it definitely isn't just the sound of air being pushed across the fan that I'm hearing! How much vibration do you feel on yours?

But seeing other posts on this forum that say that a headstock noise level of 80dB is considered normal, I think I'll mount the motor into the headstock as is today* and see how everything sounds/shakes when put back together.

Speaking of tolerant wives, I'm also quite lucky. My "workshop" right now is the "veranda" which really should be some sort of summer dining room, and sitting out there is a pot with denatured alcohol for cleaning off parts which is borrowed from the kitchen. Of course there is a price-- amongst other things, she expects a new bathroom to be added to the house this summer!

*This also depends on the wife and the weather. If it stays sunny, then we'll be outside picking cherries, working in the garden, etc. and it will get put off till tomorrow.