Jackshaft on a compressor?

[Logan W]

So what do you guys think about running a jackshaft on a compressor to change the gearing and make it easier for the motor? I'm on the market for a new compressor and there is a slew of big hp 3 phase compressors priced dirt cheap in my area. The particular compressor I'm looking at is a 20hp Kellogg 462TV mounted on a 120 gallon tank. I do not have 3 phase and nor will I due to cost. A vfd is completely out of the picture for a compressor. A rotary phase converter would need to be considerably bigger than 20 hp. And 20hp single phase motors are non existant. So what if I bought a new 7.5 or 10hp single phase baldor and used a belt driven jackshaft to comprnsate? This idea literally just popped in my head so i haven't had a long time to think all the details through. But I'd like to hear your comments on this. Thanks guys!

 

[Firebrick43]

It would work if the compressor is not to slow. Many compressors need 400-450 rpms(some more) to splash lube the bearings and cylinder walls or maintain correct oil pressure if it is pressure lubed. The compressor will be queiter. Also make so you don't make the drive sheave to small. Belts need a certain amount of wrap to transmit power. Many closely spaced sheaves(which yours will be) start slipping as you approach a 3:1 ratio.

 

[MacMcMacmac]

Bad idea. You.re going to have to slow down that 462 so much to run it off of such a small motor, that you might have trouble with lubrication, especially the small ends. Smallest motor I ever saw on a 462 was 15hp. Thats also a lot of iron to get moving with such a small motor. I don't see how you get any benefits from this, except a big tank. I've seen DeVilbiss 445 compressors running off of 7.5hp for HVAC purposes and they barely make 100psi. That's a 15hp compressor pump.

 

[Firebrick43]

http://kellogg-american.com/wp-content/uploads/2015/07/K462-Manual.pdf

Page 12, needs 12-13 hp to maintain 400 rpm so Macx3 is correct, 15hp min.

 

[MacMcMacmac]

Hah! Reading that manual tells me Kellogg is as much American these days as chop suey.

 

[EOC_Jason]

Yeah after looking at the manual I don't think even a 10HP will cut it... Like other's have said you need a certain RPM for both proper lubrication and decent pulley size on the motor.

 

[Packard V8]

You want to go weird? Consider driving it with two 7.5hp motors on opposite sides of the pump. I've seen it done, usually for redundancy, where the motors alternate starts. However, there's no reason both couldn't run simultaneously; voila, 15 hp single phase.

jack vines

 

[A_Pmech]

You want to go weird? Consider driving it with two 7.5hp motors on opposite sides of the pump. I've seen it done, usually for redundancy, where the motors alternate starts. However, there's no reason both couldn't run simultaneously; voila, 15 hp single phase.

jack vines

Poor man's soft starter.

 

[dr_clyde]

If you really need that much air, perhaps you should look into a screw compressor. No matter how you slice it, that much air is a power hog.

What are you doing that you need a 20HP compressor in a home shop? I know industrial machine shops that get by with less.

 

[MacMcMacmac]

Chop Suey is American.

https://en.wikipedia.org/wiki/Chop_suey

Stop confusing the issue with facts

Ok, as American as chopsticks, ha!

 

[bastage]

2nd compressor maybe.. different start and stop psi so they don't kick on at the same time. Given the cost of that pump you could probably do it way cheaper with more everything.

 

[motofool33]

starting with a 15hp or 10hp might be alot easier.

i converted my 10hp quincy to single phase love it.