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

[julianf]

Im tidying, and re-visiting the compressor.

Here's a photo -

My issue is that, in order to get the pulleys to line up, like this -

The motor has to be offset on the mount, like this -

Which leaves the foot on the right hanging over the edge, so nothing to bolt into -

But there's plenty of room on the other side -

Regardless, i need some way to move the motor, to tension the belt.

Just welding a plate on the top would be awkward, as the motor foot mounting holes come just on the line of the mount support.

Its like i need to elevate the motor or something - im sure its so obvious, but i just cant think up an elegant solution!

Id also like to be able to wind the motor back to tension the belts. I guess i could lever something in there, and nip up the bolts though.

So, can you suggest to be how to do this?


(no, its not the original motor... it was engine driven originally, on a vehicle, i think)

 

[dobbslc]

What about some 10mm flat bars bolted to the original mount on the tank then tap them for the new motor fixings?

 

[brightspark]

weld a couple of angles on one each side of the motor mounting plate higher than original platform and weld a new plate wider on top with slots in then nut and bolt motor down

 

[WorkshopChris]

Can you mount motor on a plate with countersunk screws from the rear and studs down from the plate that use the existing slots on the tank.

 

[eLuSiVeMiTe]

Could you Mount the motor inline and tension with a freewheeling adjustable pulley?

 

[julianf]

If i were to do the plate (or bars) under the motor, the bolts mounting the plate to the original mount would also need countersinking, as there's no room under the motor. And then doing them up would be troublesome, i think. I guess i could weld the tops to stop them spinning - that would probably work.

If i raise the mount, with angle, then the uprights are still going to be just where i want the bolt to go through.

Adding another pulley seems like a sedgehammer to crack what im sure is a simple problem.

I reckon the best plan so far is a plate with countersunk and welded bolts going both ways.

 

[Paul.]

I would make a hinged motor plate, a couple of bits of 8 or 10mm plate would be ok, it would raise the motor a bit but there is plenty of room there for it, then to tension the belt just use the screw to jack up the top plate,

 

[brightspark]

weld the angles on to the top of the platform clear of where u want to bolt motor to then weld larger plate on top u can then nut and bolt motor down no problem

 

[hazzabo]

how about bolting some unistrut or hilti channel across the motor platform so it overhangs the side, then another couple of short channels on top of these at right angles? Bolt the motor to these using channel nuts and you can slide the motor along to tension the belt. Will lift motor by 40-60mm though.

 

[normspanners]

Put the motor pulley on the other way round that then will move the motor more to the right as in the third picture, enough to get bolts in, all you need to do is weld a flat bar to extend the motor / compressor mounting bed, but first slot the bar to suit your needs, use the slotted bar to mark the bed in the position that is needed slot the bed, then weld the bar onto the side of the bed but level with the bed , job done you also need to move the pulley to get the belt guard you are going to make to clear the pulley ??

 

[eil]

21mm unistrut under the motor then slot the compressor mounting plate for your adjustment.

 

[rikrobson]

I'd Fab up a mounting plate and put that on some unistrut with zebedees to hold it down. Then you san release tension on the zebedees and slide the motor along the comressor to tension the belt. If you wre being really fancy you could fab up a screw to push pull the motor along the unistrut.

 

[Screwdriver]

Turn the motor 90 degrees and mount it vertically to a plate hinged at the bottom. The electronics box will be uppermost, a simple screw/spring can set the tension.

 

[Mee]

Julian, had a similar unit, but much larger and same layout.

They used a U section with a slot cut out for most of its length, the motor bolted to this and used the inside of the U to captivate the nuts and the slots allowed it to slide one plane, each end had a plate welded underneath and these had slots at 90 degrees to the slides to allow some sliding in the other plane which is front to back of your tank.

You mount the top of the U section to give you lengthways movement in the motor to tension the belts, and if you weld a couple of bits of threaded bar to the captive nuts and fit an end plate with a hole to the end of your U channel you can drop a couple of nuts on and tension evenly to tighten your belts.

 

[julianf]

Thank you for the ideas. I realise I need to ask another question -

Whilst I've done cambelts etc. I've never even once tensioned a belt like this, so I don't know how much bother it is!

Say, if I just had slotted holes, or unistrut, etc. I'd need to somehow move the motor back with the belt fitted, and then do up the nuts whilst holding the motor. Seems like I won't have enough hands? It would be a bit random as to if I got it all square also?

...but motors are often mounted with slots, so I'm thinking it can't be as hard as all that?

 

[julianf]

I would make a hinged motor plate, a couple of bits of 8 or 10mm plate would be ok, it would raise the motor a bit but there is plenty of room there for it, then to tension the belt just use the screw to jack up the top plate,
View attachment 109231

I'm thinking that if I put the pivot on the near side, then the tension would be trying to pull the motor up, rather than push it down, right?

Seems it would be simpler to adjust the angle of the plate that way, as some screws could just work against the upward force of the plate?

But then the motor weighs a lot (needs consideration when I lift it) so maybe that is too much tension anyhow?

For the hinge - just any chunky door hinge type thing?

 

[Screwdriver]

I'm thinking that if I put the pivot on the near side, then the tension would be trying to pull the motor up, rather than push it down, right?

Seems it would be simpler to adjust the angle of the plate that way, as some screws could just work against the upward force of the plate?

But then the motor weighs a lot (needs consideration when I lift it) so maybe that is too much tension anyhow?

For the hinge - just any chunky door hinge type thing?

TBH, I don't see how lifting the motor up and down is going to have any effect whatsoever on belt tension.

 

[julianf]

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.

 

[pedrobedro]

TBH, I don't see how lifting the motor up and down is going to have any effect whatsoever on belt tension.

It would work by swinging the motor through an arc but you would need a lot of adjustment to get the belt tight. Car alternators use this principle but they have another pulley in the mix usually. Cut the mount off and put it where you want it then weld it back on.

 

[Screwdriver]

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.

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...