How to mount this motor, so i can still tension the belt?

[pedrobedro]

Bolt the motor down and slot the holes the pump is mounted on.

 

[Screwdriver]

Here's what I'd do.

Probably also have captive studs on the compressor frame for easy adjustment. Plate is permanently bolted to the motor.

 

[julianf]

Yes. I appreciate how it is supposed to function. Here's what I am saying:

You need to raise the platform a considerable amount to achieve a negligible adjustment. The motor would have to be perfectly mounted to start off with and I am not sure that half an inch or so is going to allow a V belt on/off unless the motor plate begins to almost rotate to vertical to take up slack.

Which is also what I was saying...

Sorry - ive looked again at your initial post (i was on my phone before, and its not easy to use...)

I guess its just depends on the angle, and the radius. Your first description was, i think, the same, just at an (aprox) 90 degree angle. Above is, what, 25 degree or somthing. I guess, in my head, i was thinking more like 40 or 45. But, obviously, radius (of arc) has a huge play on things too.



The simplest solution has got to be that given by normspanners - im just not sure how easy it is to tension these on slotted holes, having never done one before.

 

[Screwdriver]

Well you probably don't need it to be "adjustable" per se, you just need to be able to fit it and forget. Slots are the easiest way and you just hold the tension with your hand while tightening down the bolts. Unless it's hidden away somewhere (and possibly even then) you will need a belt guard.

If you don't fit a guard, I'm gonna play doubleboosts video atcha.

 

[julianf]

Ive deliberately not watched that video. I can imagine what happens.

My friend runs his 6hp lister engine with a belt driven alternator, whilst his dog runs around the workshop... You might have gathered by now quite how precious we are about our hounds....


So, in conclusion, you reckon the slotted plate is easy enough to tension up / align? If i turn the pulley around to offset the motor further, and just weld another plate on the top (the original under the motor has a whole load of slot attempts by a previous owner), it will be good to go (not overlooking the belt shielding)?

 

[Pete.]

Take a mini grinder and cut the top off the old motor mount leaving in the uprights. Weld on a wider bit of plate.

 

[Paul.]

A hinged motor plate works perfectly well, I've done it many times on all sorts of industrial and packaging machinery builds, if you get the geometry correct you only need a small amount of adjustment to tension the belts, here is a very simple polisher I built using this method.
All sorts of ways to do it though varying from bodgery to an engineered solution, I don't do the former.

http://www.mig-welding.co.uk/forum/threads/bench-polisher.12184/

 

[Screwdriver]

I'm not sure how important it is to swap the pulley around on the shaft. It does look slightly backwards but in this case that's helping keep down the width. But yes, since the motor doesn't have slots, fit a motor mount that does. You could just drill and bolt some studs for the plate to slide along but frankly, what with this being a welding forum...

It will be very easy to align and tension. Alignment will be +/- 10mm even if you make everything to a decent dimension, there will be enough slop so long as the studs are in appx the right place. Tension is leterally just give it a shove while nipping up the bolts. No real need to get all clever cloggs with springs, hinges and whatnot. Looks like you'll have a dual belt and the weight of the belt will give it enough grip to drive!

 

[Screwdriver]

A hinged motor plate works perfectly well, I've done it many times on all sorts of industrial and packaging machinery builds, if you get the geometry correct you only need a small amount of adjustment to tension the belts, here is a very simple polisher I built using this method.
All sorts of ways to do it though varying from bodgery to an engineered solution, I don't do the former.

http://www.mig-welding.co.uk/forum/threads/bench-polisher.12184/
View attachment 109244

Well yes. In fact that is what I am suggesting in my post where I say mount the hinge at 90 degrees.

In the first diagram, the adjustment geometry is way off. In your above example it's totally different with the pivot point below the pulley centre meaning the adjustment is effectively linear between centres.

 

[Paul.]

Well yes. In fact that is what I am suggesting in my post where I say mount the hinge at 90 degrees.

In the first diagram, the adjustment geometry is way off. In your above example it's totally different with the pivot point below the pulley centre meaning the adjustment is effectively linear between centres.

It was never meant to be an engineering drawing, just an idea for julianf to consider as an option,

 

[Screwdriver]

It was never meant to be an engineering drawing, just an idea for julianf to consider as an option,

To be fair we have turned full circle. You posted an image of a mechanism:

Someone says whaddya think of that, I say it won't work because the pivoting geometry is all wrong you say yes it does work and post a picture of an entirely different geometry.

You go on to say the rough sketch was "just an idea" implying that you do not (now) vouch for the accuracy of the mechanism and therefore you are agreeing with my initial comment that it wouldn't work.

Q.E.D.

Time for tea.

 

[knighty]

aren't the diagram and the photo above pretty much the same thing ?


Julian, don;t worry so much about tensioning the motor, get it pretty much right, take up tension on bolts, and then shove it by hand or with a bit of bar while you tighten the bolts more

the belts don;t need to be that tight

if you struggle, you can do up the bolts tight enough to stop it sliding, and then whack the motor bottom plate with a hammer and block of wood to get it just right

 

[julianf]

Please dont start rowing, as it discourages anyone else from continuing to contribute.


Ive found a bit of plate, so im going to start chopping shortly....

 

[Screwdriver]

It's all just a bit of fun

 

[brightspark]

If the motor is mounted on a plate that pivots (is hinged) on one side, the motor can be moved on an arc, relative to that pivot point.

Points on that arc will be nearer or further from the fixed position of the compressor pulley.

but it would have to be adjusted well up to get any arc more than a few inches and be tigh ish before u even started

 

[julianf]

and

 

[julianf]

This is where im at:

Not my holes -

Ive turned the pulley, and cut a plate for the base - going with the slotted holes -

A bit of an overhang. The plate was 2nd hand, and was the corner of something, so ive left the lip for strength, not that it probably needs it -

I guess ill take off the paint and weld it up. I may plug weld it, but i think it might all vibrate?

Then work out what bolts im going to use, drill some holes, and grind them into slots.

 

[Mee]

Please dont start rowing, as it discourages anyone else from continuing to contribute.

That's hoping Julian, but at least I wont get the blame.

Its a pity you aren't nearer to me as I have a set of adjustable slides you could have had for nothing.

 

[mpats]

Its a pity you aren't nearer to me as I have a set of adjustable slides you could have had for nothing.

Isn't it just the way, no one ever seems to be close to you............

Good luck with it Julian, my wood lathe is similar, loosen a holding bolt and lift the motor to loosen the belt then move it up or down the pullies to change the speed, little bit of downwards pressure on the motor when you do up the holding bolt again and it's more than enough tension.
I think looking at your design I would have been tempted to have the hinge at the front (towards the other pulley) so you could push the motor down and tighten up a bolt to tension.

 

[slim_boy_fat]

That's hoping Julian, but at least I wont get the blame.

Its a pity you aren't nearer to me as I have a set of adjustable slides you could have had for nothing.

Courier?