need compressor advice

[motox101]

I purchased an 80 Gallon lay down tank from Craigslist with what appears to be a Kellog 331tv pump and peerless 5 hp 3ph motor. I intended to use this in my shop but have since found that the previous owner must have droped it and then tried to weld one of the legs back. I have read enough about compromised tanks and decided to purchase another tank.

I picked up an Ingersoll rand tank same size. it came with a 10/15 hp ph3 motor. I have read a little bit about phase conversion or using a vfd but not really sure the cost benefit is worth it. it might be easier just to purchase a 5hp ph1 motor.

Questions:

1. Would it better to use the motor I have (unknown condition even though the last owner said it worked) or just get a ph1 motor and match to pump?

2. do I need a magnetic starter for a ph1 5hp motor (1750 rpm, 184t frame), if so will either of the pictured work?

3. Outside of changing the oil/filter and pre maintenance advice before starting this pump?

 

[MacMcMacmac]

I don't know what you have for power supply where you are, but that is a 7.5 hp pump, so if you can power it properly, you can buy a 7.5hp single phase motor and the proper motor pulley and get some extra cfm out of it. You might get enough for the other motors to take some of the sting out of the price.

The Siemens starter is too small to run your compressor at 5hp 1ph.

The Furnas may be big enough, although they have to be de-rated for 1ph operation, so it may also be too small.

VFD seems like a pricey way to hold onto a 3ph motor of unknown conditon. Others can give you better guidance on that.

As far as the compressor is concerned, if you can turn it by hand and it makes a popping/moaning sound, you should be ok. Make sure the interstage safety valve is present and of the proper pressure range. it should be about 60-80psi. If it pops in operation, your HP valves are bad. Sometimes people put in 200psi valves when it pops, so they can keep using it as is, not knowing they have just converted their machine into a very inefficient single stage compressor that runs hot as a firecracker.

You can put a 1/4", 60psi gauge in there and see what it reads. It should read fairly constant with just a bit of oscillation due to pumping. If it is jumping wildly from 0psi to discharge pressure, the LP valves are bad. If it reads much below 30-40 psi, the LP valves need work, since they are not sealing well enough.

Good luck on the project. This will be a nice machine when finished.

 

[motox101]

Hey thanks for the reply!! Great info

the 60-80 psi interstage safety valve is separate from the tank pressure relief valve ,correct? Is this on the output of the pump? Is this like a compression test for the pump valves?
I didn't see where this is listed as a 7.5hp pump everywhere I have looked says 5hp. But
there is no exact model number on this unit

 

[motox101]

320 meter, 5 separate 220v outlets. Just finishing building my garage

 

[MacMcMacmac]

Ok, my bad, I confused yours with a Kellogg 352, which is a bigger unit but looks almost exactly the same. I would think the Furnas would be big enough for your 5hp, but find out for sure.

The interstage valve is somewhere on the head, or may be tucked up under the head near the intercooler up front.

The valve test is for valve condition. The valves may be worn, dirty, have broken springs, be rusty, not seated properly in the head, or any combination of these things which would make them act up.

I once had a Kellogg that would blow back through the filter very intermittently. Turned out the center hole in one of the valve discs was machined a hair too tight and would not seat properly every few strokes. It doesn't take much.

 

[motox101]

I looked the unit over and pulled up a parts diagram. I must be missing the valve your talking about

 

[MacMcMacmac]

I looked the unit over and pulled up a parts diagram. I must be missing the valve your talking about

Hmm. Yours might not have one. A Kellogg 340 was actually the only 2 stage compressor I saw that didn't use one, so maybe Kellogg did this on some of their units. Seems like a bad way to save a few bucks.