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  1. #1
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    Default removing elec motor fan

    Gday All.
    Ive got a 1.5Kw 3 phase motor that I intend to fit to my lathe with a VFD. I bought the motor and VFD pretty cheap a few months ago from a bloke who had fitted a single phase. The motor is basically new but being Chinese in origin the bearings are a bit sus. They are just 6205Z so easy & cheap enough to replace with better quality.
    However there is a plastic cooling fan on one end of the armature. It appears to be just a push fit then retained with a steel flanged retaining ring that looks like its swagged into place.
    I've had a little bit of a lever at it with a couple of screwdrivers (as you do) but as expected no sign of movement.
    No wanting to bust the fan I thought I'd ask here for any tips or tricks for non destructive removal.
    I suspect I will have to cut the retaining ring to remove the fan blade which then means I have to come up with something else to hold the fan in place.
    A 12 volt computer type fan attached to the rear of the existing fan cover might be the go.


    motor fan 001.jpgmotor fan 002.jpgmotor fan 003.jpg

    Thoughts please?
    Thanks
    Peter

  2. #2
    BobL is offline Member: Blue and white apron brigade
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    Default

    Use a Dremel with a thin kerf cutting wheel to cut through the small steel flange.
    Apply lube and lightly Heat the plastic with a hot air gun and that should be enough to get it off.
    When replacing the fan the steel flange can be replaced with wire or a lightweight hose clamp.
    If the weight of the adjustment screw of a single hose clamp upsets the motor balance - use two shortened hose clamps and adjust the lengths so the screws are approximately opposite each other.

  3. #3
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    Default

    Hi Peter,
    Based on the photos I suspect the retaining ring is a compression type that needs to be split to remove the fan, for replacing, a hose clamp would probably suffice, if out of balance then add some lead strip under the clamp opposite the worm screw. Another alternative would be an ear clamp as you see on some hoses these days, but somewhat expensive if you don't have the crimping tool. I doubt a computer type fan as a replacement would move the volume of air needed for cooling, but also bear in mind that reducing the speed somewhat of the motor via a VFD reduces the volume of cooling air. I had this problem and ended up mounting a 12 volt computer fan on mid axis to blow air across the frame, works well. Alan.

  4. #4
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    Default

    Thanks
    Pretty much what I suspected. I have a small Band-it tool and some small, preformed clamps. I might be able to get one of those on it when it goes back together. If I can it would weigh less than a screw type clamp.
    Desperate men and all that.

    Alan
    There are some pretty powerful computer fans available these days. It wouldn't be any problem to get one that would cover the entire end of the current fan guard. Something like this can be had for around $30.

    I'll see how I go. Its not a high priority project

    thanks for the suggestions

    peter

  5. #5
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    Default

    Cut the retaining band to get the fan off, probably in 2 places.
    Make a replacement 2 piece retaining ring/band and screw the 2 halves together, I'm thinking 6mm cross section with M4 screws, its going to be bulkier than the present ring but not enough to impede air flow. Removing the fan a second and third time will be a doddle.
    IME electric motor cooling fans are made from the crappiest most fragile plastic known to man, handle the fan with great care.

  6. #6
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    Quote Originally Posted by bob ward View Post
    Cut the retaining band to get the fan off, probably in 2 places.
    Make a replacement 2 piece retaining ring/band and screw the 2 halves together, I'm thinking 6mm cross section with M4 screws, its going to be bulkier than the present ring but not enough to impede air flow. Removing the fan a second and third time will be a doddle.
    IME electric motor cooling fans are made from the crappiest most fragile plastic known to man, handle the fan with great care.
    Great idea Bob. Hearing you about the crappy plastic. Hopefully there will not be a 2nd or 3rd removal in my lifetime.

    Peter

  7. #7
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    Hi Peter,

    Will it not pull off with a pulley removal tool ?
    Best Regards:
    Baron J.

  8. #8
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    Quote Originally Posted by BaronJ View Post
    Hi Peter,

    Will it not pull off with a pulley removal tool ?
    I don't think Id get the legs of a puller behind the retaining ring and the fan itself is way to flimsy. I think (although I didn't really look that closely) that there is a groove in the shaft that the plastic hub of the fan sits in as well.
    Typical of things these days. It only has to last just past the warranty period

    Peter

  9. #9
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    Hi Peter,

    I don't think that ring is swaged on to the fan ! I think that you should be able to pull it off with a puller if you are careful. If the end of the shaft was not rusty, the whole lot might just slide off. There is a centre there so the puller screw won't slip. The hard bit would be getting the puller toe's behind the lip on that ring.
    Best Regards:
    Baron J.

  10. #10
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    There seems to be a problem with this thread on the forum.
    I'm getting email notifications of reply's, which I can read in the email but they are not showing on the forum itself. I have been refreshing the page too.
    So far there's been replies from
    eskimo

    Here is the message that has just been posted:
    ***************
    Knock the rear endshield back and pull both off together.


    and BaronJ

    You might find that the brown piece unscrews to release the fan. Grab the other end of the rotor and use vise grips if you can't move it by hand. Its usually just a wedge.

    Is it just me or are others not seeing these?Peter

  11. #11
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    Quote Originally Posted by BaronJ View Post
    Hi Peter,

    I don't think that ring is swaged on to the fan ! I think that you should be able to pull it off with a puller if you are careful. If the end of the shaft was not rusty, the whole lot might just slide off. There is a centre there so the puller screw won't slip. The hard bit would be getting the puller toe's behind the lip on that ring.
    I'll have a closer look tomorrow. That would be ideal.
    I've been crook with the flu for 2 weeks so I couldn't face doing much in the shed today. Sat on my backside most of the day and then started feeling guilty that I hadn't done much. The worst part is I've been on holidays for those 2 weeks but will be well enough to go back to work on monday. We had a trip planned but had to cancel that as we were both crook.

  12. #12
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    Hi Peter,

    It's not nice to have the flu ! Its a couple of years since it floored me ! Ended up in hospital unable to breathe. Surprisingly I'd had a flu jab about a month earlier. It wasn't until the doctors told me that the flu jab doesn't cover all the flue variations. Up to that point I blamed the jab.

    Anyway back to your mysterious Emails. I was reading your original post and looking at the pictures whilst typing and hit the submit post key. So I went back and deleted it and typed a new reply. So what you got was my deleted notes.

    Continuing: Quite some time back I needed to get a bearing off a flexible shaft ! So I made a small puller from four dome head 2 BA screws and a bit of 1/8th " inch plate. I drilled five holes in a "X" pattern and threaded them 2 BA. I used the heads of the screws as toes and as it happened the shaft collar was also threaded 2BA. The plate was simply screwed onto the shaft and the screws threaded into the plate so the heads were behind the bearing, then rotated the whole lot to pull the bearing off.

    Actually it was a waste of effort ! Because I managed to bend the shaft putting the new bearing on
    Best Regards:
    Baron J.

  13. #13
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    Quote Originally Posted by BaronJ View Post
    Hi Peter,

    It's not nice to have the flu ! Its a couple of years since it floored me ! Ended up in hospital unable to breathe. Surprisingly I'd had a flu jab about a month earlier. It wasn't until the doctors told me that the flu jab doesn't cover all the flue variations. Up to that point I blamed the jab.
    Luckily we haven't been that bad that we required hospital time. Id had a jab but my wife hadn't and we both got it in similar intensity

    Quote Originally Posted by BaronJ View Post
    Anyway back to your mysterious Emails. I was reading your original post and looking at the pictures whilst typing and hit the submit post key. So I went back and deleted it and typed a new reply. So what you got was my deleted notes.
    That explains that then. [/QUOTE]

    Quote Originally Posted by BaronJ View Post
    Continuing: Quite some time back I needed to get a bearing off a flexible shaft ! So I made a small puller from four dome head 2 BA screws and a bit of 1/8th " inch plate. I drilled five holes in a "X" pattern and threaded them 2 BA. I used the heads of the screws as toes and as it happened the shaft collar was also threaded 2BA. The plate was simply screwed onto the shaft and the screws threaded into the plate so the heads were behind the bearing, then rotated the whole lot to pull the bearing off.

    Actually it was a waste of effort ! Because I managed to bend the shaft putting the new bearing on
    Don't you hate that sort of thing? I did something similar many years ago pressing a new cam gear onto a 6 cylinder engine crankshaft. My own fault, in a rush (using a press at work during my lunch break). Didn't set it up as good as I should have, ended up with about a .015" bend in the crank. I was able to straighten it though, by setting it up between centres on my old lathe, with a bit of plate across the ways and using a small screw jack. I ended up having to push it about .030" the other way just to get past the spring. I ended up with about .0005" run out which was easily taken out by the bearings. Ran that engine for years with no problems.
    Peter

  14. #14
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    Quote Originally Posted by bollie7 View Post
    There seems to be a problem with this thread on the forum.
    I'm getting email notifications of reply's, which I can read in the email but they are not showing on the forum itself. I have been refreshing the page too.
    So far there's been replies from
    eskimo

    Here is the message that has just been posted:
    ***************
    Knock the rear endshield back and pull both off together.


    and BaronJ

    You might find that the brown piece unscrews to release the fan. Grab the other end of the rotor and use vise grips if you can't move it by hand. Its usually just a wedge.

    Is it just me or are others not seeing these?Peter
    that was me..I deleted what I said after I had a closer look at the picture...

  15. #15
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    Bollie7 when you say that there is a groove on the shaft that the plastic fan sits in, I suspect then that there will be retaining fingers on the plastic fan that are sitting in the groove. In saying that once you remove the metal collar the fan should should come off fairly easily (you may have to jiggle the fingers out of the groove). Can you use something like a small crows foot lever (I would use 2 of them) to get behind the metal collar to remove it ?.https://www.ebay.com.au/itm/4-Piece-...-/322599265338
    All The Best steran50 Stewart

    The shortest way to do many things is to do only one thing at once.

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