dresser series 600 compressor

[ashman]

I bought a dresser air compressor and picked up a new 1 phase motor to run it. It seems to run great, but I am having no luck finding an inlet filter for it.




Also, how are the air lines below supposed to be connected?


It appears to me that the connection circled on the left is just for a gauge or something, but the connection on the right appears to open a valve when the pressure switch turns off, which would make me think it should attach to the copper line running to the compressor.

Anybody got a link to a manual?

Any help is appreciated.

 

[hawkerxj]

I don't have a manual, or any experience with the Dresser, but i'll tell ya what I think since no one else has replied. If it is set up to turn on and off, looks like the unloaded on the pressure switch should be connected over to the port in what I think should be the check valve. And then add a gauge to plug the hole in that tee like you mentioned. However with those small lines going up to each of the intake valves, it may be set up for constant run. In that case, and I'm guessing here, you would want to leave pressure in the line going to the bearing housing and up to the heads. My guess is that there is a diaphragm or something to hold the intake valves open after it is up to pressure and let the pump freewheel. Is there a check valve in or under that manifold to the right of the motor? I think either way, there should be a line going as per the image attached.
PS What size motor is that, and is there a ground wire?
Hawker

 

[ashman]

Thanks for the reply. I ended up hooking it just as your have in the pic. Everything seems to work correctly, so I guess that is correct, or at least correct enough.
It originally came with a 10hp 3 phase motor. The motor that is on it is a 7.5 hp 1 phase. It doesn't seem to labor, or get hot filling the tank so I think it's going to be fine. If it does have any trouble I'll buy a smaller pulley for it.

Oh, and I did add a ground. In the pic above I hadn't run it yet.

 

[hawkerxj]

Glad it worked, I did see one for sale today that show different plumbing.

 

[hawkerxj]

Also, a 7.5 hp is an awful big motor to run off that pressure switch. Did it come with a mag starter?

 

[ashman]

No mag starter.
Looked at the rating on the switch and for 1 phase it's only rated for 3 hp. Didn't notice that before. Its supposed to shut off at 175 and come on at 145, but it's actually 150/120 so I was thinking of replacing it anyway. Guess I have more reason to do it now.

 

[Citation]

Nothing wrong with not running to the higher pressure. Running too big a motor through the pressure switch however...
Really, if you keep the big motor you don't need a new pressure switch, that should be adjustable. You need the starter.

 

[hawkerxj]

As Citation said, the pressure switch is adjustable. Tightening the nut on the larger spring will increase the cutoff pressure. Adjusting the nut on the smaller spring will change how much the differential pressure, which seems to be fine at around 30psi. Since you have a smaller motor on there than what it came with, I would just leave it. You could measure the amp draw on the motor and see if you are currently getting up to full load amps(FLA). Then determine if it's a good idea to crank it up. If you are already into the service factor on the motor at 150psi i would definatly leave it, or even turn it down till it is just hitting FLA at cutout pressure.