Electric motor replacment for gas engine - compressor

Steevo · Feb 21, 2012

I am considering the purchase of an Ingersoll Rand T-30 2-stage compressor.
The compressor was originally factory-equipped with a Kohler single-cylinder 11HP gas engine.
Would a 5HP 230V single phase motor be sufficient to power this?
I can't find any online specs as to the pump HP requirements or even the CFM ratings for it.
The pump is a 2475.
I was thinking that I once heard that gas engines had to be about twice the HP as an electric to perform the same work.

Update: I found the pump specs online. 5HP will run it.

930dreamer · Feb 21, 2012

Did you pick up the IR compressor?

larry_g · Feb 21, 2012

Steve

Found this http://fileserver.ingersollrand.com/DocumentLibrary/Overall Recip Compressor Brochure.pdf

It looks like the 2475 is the pump F is the tank 11 is the engine hp G might be Kohler engine. Looking about I find that pump is also used on 5 & 7.5hp motors. What I couldn't find was the pump speed when used with a 5 hp motor. The pump may also have an unloader that vents the pressure and controls the engine speed that will have to be dealt with.

on edit; found some more info on pump speed vs hp required. http://buy.gissn.com/Pump-Air-Compressor-p/4r800.htm

lg
no neat sig line

Steevo · Feb 22, 2012

larry_g said:
Steve

Found this http://fileserver.ingersollrand.com/DocumentLibrary/Overall Recip Compressor Brochure.pdf

It looks like the 2475 is the pump F is the tank 11 is the engine hp G might be Kohler engine. Looking about I find that pump is also used on 5 & 7.5hp motors. What I couldn't find was the pump speed when used with a 5 hp motor. The pump may also have an unloader that vents the pressure and controls the engine speed that will have to be dealt with.

on edit; found some more info on pump speed vs hp required. http://buy.gissn.com/Pump-Air-Compressor-p/4r800.htm

lg
no neat sig line

Thanks for that Larry

metalmagpie · Feb 22, 2012

I know that a 7.5hp electric equals an 18hp gas engine.

Slick111 · Feb 22, 2012

Did this my self 5 HP motor works fine but make sure it is at least 20 to 22 amps and you have to disable the head unloaders that are from the gas motor set up I ended up getting two tanks stacking them on top of each other and hooking them to gather as the gas motor compressors are always only 30 gal tanks to be used portable on work trucks only reason I did all this was due to getting ever thing real cheep.

Steevo · Feb 22, 2012

Since I bought this pump & tank today, I could use any information, such as Slick111 mentioned regarding unloaders. I need to know what changes when swapping from gas engine to electric motor.
What do I need to do? I Plan to use a 5HP Baldor compressor duty motor.

Slick111 · Feb 23, 2012

The unloaders are connected to the gauge/pop off valve to the top or heads of the compressor the allow the gas motor to keep running when the set pressure in the tank is reached unlike a electric motor that simply shuts off. I cant tell exactly the set up with out seeing your compressor or even if it still there but you should see lines and such even if the gas motor is removed.Hope this helps you

Steevo · Feb 23, 2012

Thanks, Slick.
Once I get it home (probably Friday), I'll get some good pictures and start a new thread about "Converting a Gas Compressor to Electric" to ask for expert assistance on any needed modifications.
Now I need to order a 5HP motor. That's gonna cost more than the compressor did.

larry_g · Feb 23, 2012

http://www.industrialairpower.com/wp-content/uploads/2475.pdf

Reading the above I noted that the electric and engine driven have different beltwheels, see note on page four, So something to be aware of. That would lead me to wonder if changes need to be made to oiling system?

http://www.irtechpubs.com/ir_pdfs/C...ressors/Reciprocating Compressor/22400394.PDF

The above doc is similar to the first but the drawings show rotations and also show, what seems to be, that the pressure control/unloader is on the tank and not integral to the pump.

lg
no neat sig line

Steevo · Feb 23, 2012

Good finds, larry_g

Mine is exactly like the unit on page 21 of the second linked document. There is a small pipe that goes from the check valve/pressure valve on the tank, up to the head of the smaller cylinder. I would assume that this applies pressure when tank pressure is reached, unloading the compression on that cylinder and allowing freewheeling until the tank pressure drops back below minimum range and the unloader valve closes.
I am assuming that, for electric operation, I'd feed my pressure switch from that tube, cap off the port that goes into the head, and set the switch to power on/off the motor at the requisite high/low pressure settings.

I may call IR and ask about the difference between the electric and gas beltwheels. I'd think it is likely to be the fan blades or the belt groove(s) more than anything.
As for oiling, these are splash lubricated by con rod dippers anyway, so that shouldn't make any difference to the oiling system. They just have minimum RPM needs.

Electric motor replacment for gas engine - compressor

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