Thread: Second Hand electric motors

Try your local council recycling / tip shop. I recently purchased a clothes dryer for about $10. Perfect working condition, have set the motor aside for a future project.

The problems with motors from washing machines and dryers are as follows.
-newer motors will spin way too fast and will need gearing down - more work
- nearly all motors from washing machines and dryers will be open frame motors meaning stuff can get into them including dust and small fingers. This can be overcome by making a cover - then it might need a better fan and thus more work
- their mounting mechanisms or bases are often "unusual" and made out of baked bean can type material. This can be overcome by remaking the base - again more work

A simple, and safer way to do this would be to try an purchase a well used lathe or WW machine of some kind and adapt the motor.
How wide a drum are you looking at? Wider drums will require a lot more power than a dryer or washing machine motor can usually generate.

I get my motors mainly from gum tree and have paid between 0 and $100.

Of the 20 or so I have bought in the last 5 years, 2 of the motors have been duds.
A 2HP single phase motor was purchased for $70 and other than making sure it ran I did not submit it to any more testing.
This one started over heating a few days after purchase.
The other was a 4HP single phase motor and was tested (but not under load) before purchase but it died after ~2 weeks or so of use.

Most of the motors I buy are 3 phase, single phase motors seem to be more expensive and more unreliable than 3 Phase motors.
Bear in mind that small new single phase motors with a warranty can be obtained on eBay for about $100.

Cheers Bob.

Not looking to make a monster sander. maybe 40cm-50cm wide for the first edition, which would be more of a learning experience. Not opposed to more work, as long as I learn things from it.

I like the idea of a lathe motor, but they are rare over here in Perth.

Originally Posted by DonIncognito

Cheers Bob.

Not looking to make a monster sander. maybe 40cm-50cm wide for the first edition, which would be more of a learning experience. Not opposed to more work, as long as I learn things from it.

I like the idea of a lathe motor, but they are rare over here in Perth.

40 cm will need a 1HP motor, a 50 cm will need more like a 1.5HP.
I agree there's not much on gum tree in that range at the mo.

Over the last three or so years I've sourced some good secondhand single phase ones off ebay. They have been mostly power upgrades for lathes, table saws etc. The last one I bought was a 3HP 13A for $60. Before that a 2HP 11A motor was bought for $50. Both these I've hitched up and had them working under load for 15mins + just to test them and they work fine A mate now has them in his machines ( mostly home hobby work not commercial ). Another 3HP 12A motor was bought cheaper at $40 locally but it needs a new capacitor and some wiring work as the knucklehead I bought if from I think has tried to reverse the polarity by switching some of the wires and stuffed it up so this one remains in limbo at the moment. All these are Chinese made motors but I have no doubt they will last for quite a few years in non-commercial machines.
Here is a spittin' image of the two 3HP I bought in looks and specs.
ELECTRIC MOTOR 240V 2 POLE 3HP 2880RPM

Stewie

An Ice Cream maker would be ideal for this application. Monstrous torque, very low speed (~60rpm). Drive system and operation is weird: The "dasher" (inside contraption and removable) is held stationary by a shaft into the innards. The ice cream container, in the ice bucket, turns via an 8-point socket onto the lid, twist-locked onto the container. Typically less than $10 at thrift shops and garage sales. I have 3 on hand.

Construction could not be simpler. Trash all but the motor and the lid. Trim the lid to the size of your drum and attach to one end of the drum. Motor mount and other end of the drum TBD. To prevent fouling, attach a large duct to the back of the motor and provide suction if there's no internal fan.

Now that you've planted the seed, I expect to build one "soon" (as in "someday").

Cheers,
Joe

I built my drum sander from a tread mill. its variable speed, balanced, I have a read out of how fast its going. and it is soft start.

It had shafts, steel frame
cost my time, plus $50 for the tread mill, ply off cuts.

GaryCard Price less

Got any photos of your setup and the motor specs Gary ? I've heard of guys using treadmill motors for their variable speed on a US WW forum. Is it a DC motor ?

Stewie

I made a 600 wide drumsander and bought a new 2Hp 1440, 240V motor new. It was around the $200 mark but I figured that the purchase would be a "oncer" so I didn't mind the price. That motor drives the drum which is a 125mm steel pipe with the axle going right through and running in bearings. From my reading the optimum speed of the drum should be 1750RPM and I got mine fairly close to that with suitably sized pulleys. The conveyor was more of a challenge. I couldn't find any information as to how to make it so I just nutted it out myself. What I wanted was to have the conveyor to have variable speed to suit any sanding operation. I found on Ebay a motor and right angle gearbox harnessed to a VFD. This set up gave me a big selection of speeds through a potentiometer and lots of torque through the gearbox. I was very lucky with this find that I paid $70 for it. In practice I have found the best finish comes with VERY slow conveyor speed. I have also found that only a very small amount of material can be taken off per pass. Even with the 2Hp motor its very easy to stall the motor if the adjustment is set too heavy.
I found that it is a very handy piece of equipment to have in your workshop and a worthwhile exercise to build it.
Oh .....the conveyor belt I used is a 120# sand paper made to the length I needed. (From The Sand Paper Man for $90?)

That's interesting. It is something I've wanted for a long time.
I've looked at all the DIY jobs on the internet but almost universally they use a shaft through a bunch of 3/4" ply or mdf circles which I thought was a pretty amateurish if not cheap way of making the main sanding drum. Your steel pipe method sounds much more robust. How do you secure the sanding belt ? Photos of that would be good too.
I looked at the specs for a Carbatec 15" sander ( Model No. SD-15B ) a while back.
Their main sanding drum was powered by a 7.5HP/415v motor and the conveyor motor was only a 1/4HP single phase.
The feed rate was 4mpm and 5mpm.
The list price though was an eye watering $6,9995.
I'd imagine that even this motor would work hard if you didn't take off a minimal amount each time as you have found with yours.
One of my scores about ten years ago was a 960RPM 1HP 240volt motor with a 40:1 reduction drive attached that was used on a brick elevator. If I could use that for the conveyor and one of my 3HP motors for the drum I'd be set to go. Hmmm. I might get them out this weekend for a look see.
Do you know what feed rate your conveyor motor gives ?

Stewie

Stewey, if you sent me your personal Email address vie a PM, I can send you a write up I did of the Work In Progress of the making of my version. Its a little large to put on to the Forum

Rod

Your machine sounds both interesting and enterprising. Have you posted pix on the Forum or could you do so?

Regards
Paul

Give me a day, i will pull it out and take some photos. the workshop is still a mess from the move from Mackay. the drum is PVC stormwater pipe 450mm long @ 90dia, there are 4 drums with different grits sandpaper is glued directly to the drum, the drum is removable to be able to change the grit, or put in bin. the motor is a DC, has a circuit board with it, then there is a lead to the controller board.

Hey what i will do is pull it down "apart" so you can see all the parts as i need to build a new bench anyway.

well I looked in the workshop container and could find it, DOo its in the storage container. lucky I went and had a look, somebody has tried to get in through the roof hatch but found steel bars welded inside the opening, the nice person could have closed the hatch. everything in the middle of the container has been wet. sheets, beds, book case just to name a few items. NOT HAPPY JAN. anyway got the drum sander out and the bench is stuffed. looks like a rebuild. I have up loaded photos to "drum sander rebuild" album