looking for info on a 50 year old compressor

[Gazz292]

I'm in 2 minds about fitting castors, or putting it in it's doghouse using the wheeled board thing it's on now, and putting it on anti-vibration mounts (which i'm trying to figure out if they are anything more than large car engine mounting rubbers)


I'll definitely change the oil (reading past threads about these compressors, and oil seems to be a personal choice, some being happy with a non detergent diesel engine oil, some using the proper stuff, i used ISO32 hydraulic oil in my direct drive sip compressor.


Looking to buy a pressure tester now, i can get a horrible looking cheapo one for as little as £20, but likely to be worn out / knackered after one use,
But i am being drawn more towards the rothenberger clones at around £70, with the 2 valves and much better looking pump.
and of course looking for a real rothenberger twin valve tester second hand.

i'm thinking a half decent pressure tester would be a handy thing to have, i could test this compressors tank every year or so, test my 2 direct drive compressors tanks before i sell them, and test the copper pipe drip leg / cooling tower thing i plan to make, ... and even test the pressure relief valve on this compressor (i think i can do this?)

 

[GRW]

I'm in 2 minds about fitting castors, or putting it in it's doghouse using the wheeled board thing it's on now, and putting it on anti-vibration mounts (which i'm trying to figure out if they are anything more than large car engine mounting rubbers)


I'll definitely change the oil (reading past threads about these compressors, and oil seems to be a personal choice, some being happy with a non detergent diesel engine oil, some using the proper stuff, i used ISO32 hydraulic oil in my direct drive sip compressor.


Looking to buy a pressure tester now, i can get a horrible looking cheapo one for as little as £20, but likely to be worn out / knackered after one use,
But i am being drawn more towards the rothenberger clones at around £70, with the 2 valves and much better looking pump.
and of course looking for a real rothenberger twin valve tester second hand.

i'm thinking a half decent pressure tester would be a handy thing to have, i could test this compressors tank every year or so, test my 2 direct drive compressors tanks before i sell them, and test the copper pipe drip leg / cooling tower thing i plan to make, ... and even test the pressure relief valve on this compressor (i think i can do this?)

Doubt you'll need AVM's. Mine doesn't move. If on castors with rubberised tyres & a couple with brake you should be grand (I fitted 2 non-swivel on one set of feet, & braked/swivel on the other end).
If plonking onto floor, then I guess you could, but a couple of timber bearers would suffice I'd have thought.

I'm afraid my pressure valve test was "yup, it works" (you can fiddle with the cut out pressure in the contactors box to raise the pressure & see if it activates - mine does).

I'd never played with a compressor before - but these aren't complicated beasties so a bit of looking & poking soon gives you an idea of what does what... just keep clear of the live contacts

 

[Gazz292]

Had a little play with the compressor today,

The motor is the noisy bit, sounds like it'll need new bearings, not something i've done before, but hopefully this motor is designed to be serviced, and it's just a case of taking the end caps off and pressing the bearings out and new ones in.

I popped the cover off the motor's 'terminal box' and found 3 capacitors in there.
i guess the oval silver one at the top is either the start or run cap, and the 2 blue ones are connected together to be the 'other cap' as i note their 150 volt ratings.

i didn't poke about too much in there incase the caps bit me (could have wanged a screwdriver across their terminals, but i've seen the ends of screwdrivers blown off doing that, so i will make up a cap discharge tool and do it properly) not that i'm going to do much in there, just change the main wires using crimped on ring terminals.

 

[Jack_K]

I'm in 2 minds about fitting castors, or putting it in it's doghouse using the wheeled board thing it's on now, and putting it on anti-vibration mounts (which i'm trying to figure out if they are anything more than large car engine mounting rubbers)


I'll definitely change the oil (reading past threads about these compressors, and oil seems to be a personal choice, some being happy with a non detergent diesel engine oil, some using the proper stuff, i used ISO32 hydraulic oil in my direct drive sip compressor.


Looking to buy a pressure tester now, i can get a horrible looking cheapo one for as little as £20, but likely to be worn out / knackered after one use,
But i am being drawn more towards the rothenberger clones at around £70, with the 2 valves and much better looking pump.
and of course looking for a real rothenberger twin valve tester second hand.

i'm thinking a half decent pressure tester would be a handy thing to have, i could test this compressors tank every year or so, test my 2 direct drive compressors tanks before i sell them, and test the copper pipe drip leg / cooling tower thing i plan to make, ... and even test the pressure relief valve on this compressor (i think i can do this?)

I would avoid one of the Rothenberger clones, I have read of people buying them without issues but that wasn't my experience. I bought one with a 1/4 bsp fitting to make a hydrolastic suspension pump, the one I received had the 1/2 bsp fitting. I managed to get a $20 discount from the Chinese seller. I could've returned it but then I would likely have the same issue with a new order. It was also questionable if the seller would refund the postage (and the total) as they weren't using eBay's official return address which says to send it to China. Once I sorted the fitting I have now discovered what I think is a bad pump seal. Once I get to almost 300psi it is difficult to get it to 300psi, the gauge momentarily peaks to 100s of psi higher, the pressure also leaks down quickly unless I close the valve which takes many turns.

 

[Morrisman]

Rated at 9 cfm, so, probably 5 or maybe 6 real world cfm. If it fires up and runs perfectly then you're doing well, but sinking a bunch of time, energy and money into getting it sorted is probably not worth the hassle.

 

[Gazz292]

I would avoid one of the Rothenberger clones, I have read of people buying them without issues but that wasn't my experience. I bought one with a 1/4 bsp fitting to make a hydrolastic suspension pump, the one I received had the 1/2 bsp fitting. I managed to get a $20 discount from the Chinese seller. I could've returned it but then I would likely have the same issue with a new order. It was also questionable if the seller would refund the postage (and the total) as they weren't using eBay's official return address which says to send it to China. Once I sorted the fitting I have now discovered what I think is a bad pump seal. Once I get to almost 300psi it is difficult to get it to 300psi, the gauge momentarily peaks to 100s of psi higher, the pressure also leaks down quickly unless I close the valve which takes many turns.

ahhh, thanks for that info.

I've discounted the real cheap pressure testers which seem to rely on the pump seals to keep the pressure in the system... i also read that the tin they are made of fatigues quickly and you end up with the pump body in your hand after 2 uses.

I had been looking at the 'vevor' ones

Pardon our interruption...

I actually tried the 'best offer' thing on that one last night, but after 3 counter offers the most the seller would reduce it by was 45p!!!

I'm going to see if i can get a second hand genuine rothenberger RP50, i want the one with the 2 valves an the pump that sits below the main plate, as it looks more substantial that the single valve version with the pump bolted above the plate.

 

[Jack_K]

ahhh, thanks for that info.

I've discounted the real cheap pressure testers which seem to rely on the pump seals to keep the pressure in the system... i also read that the tin they are made of fatigues quickly and you end up with the pump body in your hand after 2 uses.

I had been looking at the 'vevor' ones

Pardon our interruption...

I actually tried the 'best offer' thing on that one last night, but after 3 counter offers the most the seller would reduce it by was 45p!!!

I'm going to see if i can get a second hand genuine rothenberger RP50, i want the one with the 2 valves an the pump that sits below the main plate, as it looks more substantial that the single valve version with the pump bolted above the plate.

The one that I bought was one of the RP50 clones like the "Vevor" one. Maybe you will be lucky, I always seem to get defective stuff. A Genuine one used is probably a far better option. I am yet to pull my one apart to inspect as even though it seems to be faulty it will work for the testing I need before I risk damaging it.

 

[Gazz292]

I worked at Newman electric motors for a while. Good motors but very heavy. They did cast iron or aluminium bodies.

Is there a way to find out the motor's bearings sizes from the serial number or any numbers on the plate?

Is there anything i need to watch out for when i take the end caps off the motor to change the bearings ? flying spring loaded bits, things i may damage using brute force etc?

 

[Seadog]

It all comes apart pretty easily. 3 years since I did mine.

 

[Jack_K]

Is there a way to find out the motor's bearings sizes from the serial number or any numbers on the plate?

View attachment 411043

Is there anything i need to watch out for when i take the end caps off the motor to change the bearings ? flying spring loaded bits, things i may damage using brute force etc?

I don't know about that brand or model but watch out for the centrifugal switch, some need to be removed first.

 

[Seadog]

Ingersoll Rand compressor resurrection

@Seadog I'm liking this, at this rate you'll be vying with @spencer 427 for the title of 'Best Producer of Beautiful Restorations' :D

www.mig-welding.co.uk

Post number 39 is what you need to look at. I had to manufacturer a cranked spanner.

 

[Colin Barron]

Some rig up a pressure washer to pressurise the tank. I have simply filled with water, then used a grease gun to raise the pressure - slow but works.

I just removed the cut out, ran up to higher pressure and turned it off for a while, maintaining the higher than pressure normally used. obviously outside, not standing next to it.
I have an old Tecalemit which looks like the same pump. I changed the oil and valve plates which were manufactured from what looked like bits of shim. (this is 30 years ago). I still runs ok.

 

[Colin Barron]

Had a little play with the compressor today,

The motor is the noisy bit, sounds like it'll need new bearings, not something i've done before, but hopefully this motor is designed to be serviced, and it's just a case of taking the end caps off and pressing the bearings out and new ones in.

I popped the cover off the motor's 'terminal box' and found 3 capacitors in there.
i guess the oval silver one at the top is either the start or run cap, and the 2 blue ones are connected together to be the 'other cap' as i note their 150 volt ratings.

i didn't poke about too much in there incase the caps bit me (could have wanged a screwdriver across their terminals, but i've seen the ends of screwdrivers blown off doing that, so i will make up a cap discharge tool and do it properly) not that i'm going to do much in there, just change the main wires using crimped on ring terminals.

View attachment 410633

Before you remove the end shields put a centre punch dot on motor and endshield to ensure correct alignment on reassembly. Do on both ends of the motor, one mark on one end and two on the other.

 

[Gazz292]

Finally managed to buy a hydro tester for a decent price, got a Boss branded one, rated to do 60 BAR for £30 off ebay, then had evri send it back to the seller claiming it was over weight on friday, got it today with instructions on the label telling them it's within the price band and to deliver it!

Tested the safety valve first with the hydro pump, begins to blow at 160 psi, SWP of the tank is 150, but i'll run it at around 130 psi i think.

Got all the openings bunged up, sealed with 'Sterling brake and air line sealant' which is great stuff, my existing air system holds pressure for weeks.
Filled it with water via the 3/4" full bore ball valve (rated for 30 BAR apparently... so it will be my air outlet tap when i'm done)

Then started pumping, the tank was tested to 240 PSI in 1973, so i took it up to 250 psi and left it there,
Came back 1/2 an hour later and it was showing 275 PSI on the gauge.... sun had been out and warmed the tank.

So that's a successful hydro test, now to get on with changing the bearings on the motor and putting it all back together... then pouring a new concrete pad for it and a new dog house.


That's the pressure gauge that came with the compressor, i'm going to swap it out for the 150 psi one that came with the hydro tester, not that i'll see it much mounted on the tank hidden in the doghouse... i have a couple of brake pressure gauges from a German train in my workshop that i use to show the pressure of the main line and regulated pressure outlets.

 

[Gazz292]

I pulled the motor apart today,
The smaller bearing on the fan end is rougher than a badgers ****, the bigger one on the pulley end is smooth so i'm debating changing it.



I gather the 'SP' and 'CH' are not tolerances, and is more like ... CH is for Switzerland?

 

[Seadog]

Change both.

 

[Gazz292]

Ordered 2 supposedly German made FAG bearings from bearing boys.

 

[Colin Barron]

c3 radial clearance for electric motors is ok, unless it something special, did you specify open type?

 

[Colin Barron]

i used Buck and Hickman north shields, for bearings and belts, they can get 'gates belts' at a decent price.

 

[Gazz292]

i went for the 'standard' clearance bearings, of the open type the same as the originals (tho i guess at the least the small one has been replaced in this motor's 50 year life)

Ohhh. i knew there was something else i wanted... a pair of belts, as the ones i have.... one is slightly longer than the other.. could see it flapping about when running, tho i guess this little pump really doesn't need 2 belts.