Motor clicks under load

Forum for Maintenance and Repair topics. Feel free to ask questions or contribute.

Moderators: HopefulSSer, admin

User avatar
JPG
Platinum Member
Posts: 34610
Joined: Wed Dec 10, 2008 7:42 pm
Location: Lexington, Ky (TAMECAT territory)

Re: Motor clicks under load

Post by JPG »

At this point I am inclined to think it is an A.O./Smith motor. I have a 230v version but cannot check the model # at this time.
╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
Mrehder
Silver Member
Posts: 8
Joined: Sun Sep 13, 2020 8:17 am

Re: Motor clicks under load

Post by Mrehder »

Motor label
Motor label
A2F1F03A-356D-42CF-801B-5A88E6FB6293.jpeg (102.98 KiB) Viewed 2208 times
Motor label
Motor label
A2F1F03A-356D-42CF-801B-5A88E6FB6293.jpeg (102.98 KiB) Viewed 2208 times
It is a shop smith. And I didn’t read the label carefully... 50hz
Does that explain things?
Do I need to convert the power to 50hz to use this?

Also included a photo of the inner sheave, which sort of shows the bend.
I’ll try to figure out if I can attach video or audio.
Attachments
7151897D-FF82-401E-9934-8AB4AB03A951.jpeg
7151897D-FF82-401E-9934-8AB4AB03A951.jpeg (88.35 KiB) Viewed 2208 times
User avatar
JPG
Platinum Member
Posts: 34610
Joined: Wed Dec 10, 2008 7:42 pm
Location: Lexington, Ky (TAMECAT territory)

Re: Motor clicks under load

Post by JPG »

I do not see a 'bump'.

I do see a fan sheave too close to the motor.

I suspect the spacer has embedded in the back of the sheave hub(they tend to do that).

I would be more concerned if you were running a 60 Hz motor on 50 Hz.

Dennis????
╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
User avatar
BuckeyeDennis
Platinum Member
Posts: 3683
Joined: Tue Jul 24, 2012 10:03 pm
Location: Central Ohio

Re: Motor clicks under load

Post by BuckeyeDennis »

JPG wrote:I do not see a 'bump'.

I do see a fan sheave too close to the motor.

I suspect the spacer has embedded in the back of the sheave hub(they tend to do that).

I would be more concerned if you were running a 60 Hz motor on 50 Hz.

Dennis????
I’m no induction-motor expert, but your thoughts on mismatched line frequency and motor rated frequency sound consistent with an article that I read a while back. Not sure if it’s the same article, but the one below has a good discussion on this without getting overly technical.

https://www.engineering.com/Electronics ... -60Hz.aspx

The only significant relationship I can think of between the Reeve’s drive ratio and the motor electrical operation is that increasing the spindle speed will generally increase the required motor power output, and thus the electrical current draw. So I suppose it’s possible that a bad winding connection could overheat at higher spindle speeds, but not at lower speeds, thus increasing the connection resistance even more and preventing proper motor operation. Seems unlikely, but I don’t have any better theories. The fact that the problem also occurs when driving a bandsaw at low speed is consistent with the theory, as is good no-load motor operation on the bench.

Come to think of it, the bad connection wouldn’t necessarily have to be in the motor. A bad power switch or cord could also cause problems. But I’d think it much more likely that a bad connection would just burn up, rather than repeatably exhibit identical symptoms over the course of many tests.
RFGuy
Platinum Member
Posts: 2740
Joined: Mon Dec 31, 2018 8:05 am
Location: a suburb of PHX, AZ

Re: Motor clicks under load

Post by RFGuy »

I certainly don't consider myself an induction motor expert so I defer to those who have already responded on this thread with excellent advice. Just my opinion, but I thought to a first order induction motors are somewhat interchangeable between 50 and 60Hz (depending on the application). I say this because we are talking about a light duty motor that isn't running continuous (24 hours a day). Of course operating a 50Hz motor on 60Hz will result in the motor running at a faster speed, but for this particular motor I think that is okay because the motor is rated at 2850RPM for 50Hz. At 60Hz with the same line voltage, this motor should now run at 3420RPM which is close to our target RPM (3450) for the the original 60Hz motor, so running this 50Hz motor at 60Hz should result in the speed control working near as expected - meaning that the speed dial should be in the right ballpark assuming new belt, good sheaves, etc.

At the link below is another write-up on running a 50Hz motor on 60Hz line frequency and what the implications are. One factor to keep in mind is these guys sell frequency converters so you do have to keep that in mind, i.e. they have a bias here and want to sell frequency converters for this application. Still, what they list is correct, but in my opinion this is more critical for continuous duty, high load motors (think large motors running in commercial applications 24/7). For a light duty motor like you have, I would assume it should work fine assuming you don't have your Mark V running for hours on end with no breaks.

Given how close the sheave is to the motor housing (and the fact that the motor runs fine outside of the headstock), I would assume that the clicking and slowing down is possibly something mechanical outside the motor (not a motor problem). Have you tried taking the headstock cover off and observing the movement and operation of the belt and sheaves? Do so with caution, wear eye protection and keep hands clear of inside of the headstock while doing this. When I first read this thread, my assumption was that the high speed adjustment is too low possibly causing the problems you are seeing. Not saying this is the case, but just to be sure what do you mean by the motor slows down when you hit "L" on the speed dial? I mean does the motor drop significantly in speed when you hit "L" or does it slow just a little? Does the motor click right when this happens or does the motor click all the time? Another option I would consider for isolating if the motor is to blame or not is you could mount the motor outside the headstock and put an external load on it. If the motor runs fine outside of the headstock with an external load (and doesn't click) then you know it is a mechanical problem and the first place to look is the sheaves.

Of course, if you intend to run your Mark V in a production shop (or even a home shop with a high duty cycle), then I would recommend getting a properly sized 60Hz motor replacement. There is some design margin built into every motor, so the additional power draw of this 50Hz motor on 60Hz will prematurely wear it and eventually lead to failure. However light duty use in a hobby shop (IMHO) should be fine I would think.

Excerpt from weblink listed below:
It will run with following problems for a 50Hz motor running on 60Hz:
-The core loss will increase and cause over heating of core.
-As the core loss will increase, the Power Factor of motor will reduce.
-The motor speed will be higher, so shaft load will increase. Motor will be overloaded at rated load.
-Motor will produce magnetic humming sound.
-Motor Bearing life will be reduced (marginal) for more speed and more load.
-Dielectric Stress on insulation will increase due to higher frequency, causes marginal reduction of life of motor insulation.

But, it is practically seen, there is not much difference in service of a 50Hz, 2HP/3HP, motors when operated at 60Hz.
http://www.50hz60hz.com/what-happens-if ... 0increase.


http://www.gohz.com/impact-of-60hz-50hz ... wer-supply
📶RF Guy

Mark V 520 (Bought New '98) | 4" jointer | 6" beltsander | 12" planer | bandsaw | router table | speed reducer | univ. tool rest
Porter Cable 12" Compound Miter Saw | Rikon 8" Low Speed Bench Grinder w/CBN wheels | Jessem Clear-Cut TS™ Stock Guides
Festool (Emerald): DF 500 Q | RO 150 FEQ | OF 1400 EQ | TS 55 REQ | CT 26 E
DC3300 | Shopvac w/ClearVue CV06 Mini Cyclone | JDS AirTech 2000 | Sundstrom PAPR | Dylos DC1100 Pro particulate monitor
Mrehder
Silver Member
Posts: 8
Joined: Sun Sep 13, 2020 8:17 am

Re: Motor clicks under load

Post by Mrehder »

Thanks for info on the hz. It’s for hobby use.

I pull the spring and sheeve off to dig deeper.

There was some friction on the key. I filed it and achieved smoother movement.
However the bigger story is that the outer sheeve sticks to the inner sheeve and doesn’t close completely (in comparison to the existing motor).
Now I suspect this is the core issue, that the motor struggles to get the sheeves apart but runs ok once they are separated.

I suspect the sheeve alignment was throw off when the inner sheeve was bent.
I tried filing the sheeve tine edges but it’s a deeper misalignment. I don’t think I can fix this by filing (could throw off radial balance) and the sheeves need replacing.
I’ll see if I can swap sheeves from the old motor to test this out.

I paid usd$120 for the motor so I think I have a parts budget.
User avatar
JPG
Platinum Member
Posts: 34610
Joined: Wed Dec 10, 2008 7:42 pm
Location: Lexington, Ky (TAMECAT territory)

Re: Motor clicks under load

Post by JPG »

At this point I have to ask 'where are you located?'. Are you running on 50 Hz or 60 Hz?
╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
DLB
Platinum Member
Posts: 1985
Joined: Fri Nov 08, 2019 11:24 am
Location: Joshua Texas

Re: Motor clicks under load

Post by DLB »

Mrehder wrote:I’ll see if I can swap sheeves from the old motor to test this out.
Will you also measure sheave outer diameter while you're swapping this out and report dimensions? I'm wondering if SS might have made other headstock changes when they did a pure 50 Hz headstock in order to get the same speeds. I'd think that if they did it would include different motor sheaves and a different belt, at a minimum. I know they don't do this on the 50/60Hz headstocks, just publish how the 50 Hz speeds deviate from normal.

Usually problems relating to movement of the floating sheave show up as difficulty changing speed rather than as motor power problems. Or, if it sticks fully closed it can be hard or impossible to get the belt on. (Been there.)

When you're changing the sheaves, be mindful of the spacer that goes between the fan sheave and the motor bearing. As noted in an earlier post, your fan sheave looks too close to the motor housing.

- David
User avatar
JPG
Platinum Member
Posts: 34610
Joined: Wed Dec 10, 2008 7:42 pm
Location: Lexington, Ky (TAMECAT territory)

Re: Motor clicks under load

Post by JPG »

As asked previously, is the motor slowing or is the quill slowing?

A sticking floating sheave WILL cause the quill to stall. It will also cause undue stress on the quadrant(porkchop).

BTW I assume Canada is 60 Hz(I looked up your location).

As for the 50Hz SS version speeds AIUI those folks use a speed conversion chart(yes they run slow).

I have in the past attempted to determine if pulleys etc. are different and did not get a definative 'yes' answer.
╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
DLB
Platinum Member
Posts: 1985
Joined: Fri Nov 08, 2019 11:24 am
Location: Joshua Texas

Re: Motor clicks under load

Post by DLB »

JPG wrote:As for the 50Hz SS version speeds AIUI those folks use a speed conversion chart(yes they run slow).
Agree that's true, just wondering if it has always been so. At least some of the 50/60 motors are labeled as such, which I think is what one would expect. Example: https://www.ebay.com/itm/Shopsmith-Mark ... SwWOJfUFDt I was wondering if the 50 Hz as designated on this motor might indicate that at one time SS made 50 Hz only headstocks. (I also noted the OP's motor is not rated for continuous duty, which also stands out among other SS motors I have seen, excepting PowerPro.)

BTW - I ran my Greenie on 50 Hz through a transformer for several years when I lived in what was then called West Germany. It ran slow and I had my own version of a speed table. Early in that experience I would frequently touch the headstock and feel the outlet air temp to see if I thought it was too hot, which I never did. No detrimental impacts, it still runs. It was a pretty benign environment though, relatively cool basement 'shop.' And, of course, 3/4 HP.

- David
Post Reply