How to add a sensible motor mount?

[julianf]

I have a compressor - small belt driven thing.

Prior to my ownership it was reterofitted with an electric motor (i think it was originally on a vehical)

Anyhow, the motor has been fitted to a flat plate on the top of the compressor that's not wide enough for the motors foot. So theyve just used two bolts on one side, and the other end of the foot hangs off the side of the compressor.


Ill have to take some photos, but its not pretty...


Anyhow, i took off the motor to fit a new belt today, and i cant get it to stay parallel to the rest of the job now. The belt pulls it around at an angle, and, besides, when its running, its all jumping about some, on account of only being half attached.


So, to the question -


I realise this is child's play for a lot of you, but what's the best way to mount this?

The compressor has a flat (plate) 'shelf' on the top of the tank, where the pump mounts, and where the motor needs to mount. But the motor needs to be offset (so about 1/3 of its foot is over the eged of the shelf) so its pulley aligns with the compressors pulley.


Is my simplest way to weld on a plate large enough to take the motor's foot, on top of the flat top (shelf) that's currently there, and then cut some slots in both it, and the original shelf below it?

Or is there a better way?

I dont have a mill thats good for ferrous here, so im wondering if a thickish alloy plate bolted to the original might do (i can CNC some slots in alloy, rather than butchering it by hand)

Again, this seems like it should be a simple job, and im sure some of you have done loads before - which is why im asking!

Thank you : )

 

[Bill Edwards]

A picture would be a good idea, much easier to come up with good suggestions when you can picture what is needed.

 

[brightspark]

weld a piece of steel plate on top chain drill some holes for the slots and open them up job done

 

[rtbcomp]

Drill 2 sets of elongated holes in a plate, one to take the motor, the other at right angles to match the plate on the compressor, that way you can adjust the motor in two directions to line the pulleys and set the belt tension. You may be able to move the pulley on its shaft to align it with the pump pulley.

 

[Wallace]

As above but add tensioning bolts by welding a short length of angle to the motor plate with long bolts/studs welded on and another angle to the base plate with holes in to pull the motor into tension & alignment.

 

[julianf]

Thank you for the suggestions. Ill take some photos of the unit later in the day and upload them.

Again, its not pretty, but it will be spot on what i want when its sorted (i have another 14cfm unit, but its loud, and has issues with extension leads)

 

[rtbcomp]

As above but add tensioning bolts by welding a short length of angle to the motor plate with long bolts/studs welded on and another angle to the base plate with holes in to pull the motor into tension & alignment.

I did that on mine, but avoid the temptation to overtighten the belt.

 

[julianf]

Here are some photos.

The unit *after* ive spent hours cleaning layers of crud off it -

another shot -

Points to note in this shot - you can just about see an unused slot in the frame between the left hand motor foot, and where the belt runs across. These are unused (part of its former life) and also... The overhang on the right hand side of the 'shelf' is fractured along where you might expect it to bend. Someones had a go at welding it previously, but, basically, its unusable.

Now a shot from the end of the unit. You can see the bolt running through at a grim angle (no proper washer fitted) and also the amount by which the other foot overhangs the 'shelf' -

And another shot of the same, showing the overhanging foot a little better (and another of the redundant slots) -

One final shot, as i had it on the camera -

I suspect the pulley on the motor should be reversed, but i cant get it off the shaft at present (i need to buy or make a puller).
The pulley on the compressor is dual, and the one on the motor is also dual, but the whole lot has been aligned so as the offset means only one belt can be used (inner on motor to outer on compressor)
Turning round the pulley should resolve this, but i think there must be a complication, or why would noone have done that in the past.

 

[Anguz]

flat plate under the motor, with new slots, move the motor back, and you wouldnt have to pull the pulley

 

[rtbcomp]

If you do decide to remove the pulley check there is only one grub screw in the hole, heat it up evenly and pull gently.

You also need a cowl on the other end of the motor to force cooling air along the case.

 

[Bill Edwards]

I'd also just weld a bit of flat plate under it, and slot the holes.
You could move the motor back at the same time, though it does look as though this'll make the whole unit bigger/wider.

 

[rtbcomp]

I guess a single belt will be fine, both my SIP and Clarke 3HP have single belts.

 

[Wedg1e]

If it were mine, and as it looks as though the motor already has slotted feet... I'd weld M8 studs to a piece of 3mm steel plate, so that the studs point up and pass through the motor slots with the motor in about the correct position to align the pulleys, then bolt the plate to the compressor using the compressor's slotted top plate. Then the motor slides along its axis on the plate to get the pulleys true, and the plate slides along the compresor to set belt tension.
Saves welding anything to the compressor on the offchance that a better fitting motor comes along

 

[roofman]

Iff you turn the pully around the grub screw is going to be on the outer side of the key..this is bad

 

[Rig Pig]

Here are some photos.

The unit *after* ive spent hours cleaning layers of crud off it -

another shot -

Points to note in this shot - you can just about see an unused slot in the frame between the left hand motor foot, and where the belt runs across. These are unused (part of its former life) and also... The overhang on the right hand side of the 'shelf' is fractured along where you might expect it to bend. Someones had a go at welding it previously, but, basically, its unusable.

Now a shot from the end of the unit. You can see the bolt running through at a grim angle (no proper washer fitted) and also the amount by which the other foot overhangs the 'shelf' -

And another shot of the same, showing the overhanging foot a little better (and another of the redundant slots) -

One final shot, as i had it on the camera -

I suspect the pulley on the motor should be reversed, but i cant get it off the shaft at present (i need to buy or make a puller).
The pulley on the compressor is dual, and the one on the motor is also dual, but the whole lot has been aligned so as the offset means only one belt can be used (inner on motor to outer on compressor)
Turning round the pulley should resolve this, but i think there must be a complication, or why would noone have done that in the past.

What make is the compressor? Just wondering as it's the same colour as mine.

 

[julianf]

Ill check for you - the compressor itself does, IIRC, have a small plate on it.

 

[Wedg1e]

What make is the compressor? Just wondering as it's the same colour as mine.

You sound like our lass:
"I get my new company car tomorrow."
Me: Oh yes, what is it?
Her: I dunno, a grey one...

 

[julianf]

Compressor itself has "Sherry and Son London" in the casting.

Tank has another plate on it, but i cant see that at the moment.

Motor (not that it matters) is a Brooke Crompton


I found this image from an old ebay listing, via google -

Unfortunately, the listing itself was not cached, and i dont think i can get to it from the image alone (i have no item number).

It looks the same sort of thing that i have though.


edit:

found the ebay listing now -

http://www.ebay.co.uk/itm/Belt-driv...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557



Also found this one -

http://www.ebay.co.uk/itm/Sherry-am...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

Looks to be the same compressor as mine, but on a larger tank.

...its not the same colour though! ; )

 

[Rig Pig]

I was wondering if it was the same make as mine as mine is gold as well, not a colour that I have seen on compressors before, but mine is a Bristol so it must have been a popular colour in the 70s!

 

[tomsutton529]

Certainly needs a new plate under the motor. Slot the holes to give you enough room to get the pulleys in line and use big washers or a bit of plate to keep the bolts square and prevent them pulling through.