Use a pump from a gas powered air compressor on an electric?

[piston farmer]

So the pump on my 60 gallon vertical air compressor went T.U.

I have a gas powered pump from a dewalt twin tank air compressor you use for remote sites. The honda motor on it has been not working right any how, so im wonder if i can cannablize the pump from it for my shop.

The gas engine was a 5.5 hp honda with the pump.

My electric shop motor is a 3 hp.

Ideas?

 

[metaleltr]

It can be done but you need to understand the differences between these types of compressors. Electrics cycle on and off based on air pressure by using a pressure switch. Gas compressors however are on all the time, they have an unloader valve that releases excess pressure. There is also a pressure controlled throttle on the engine, as pressure increases the engine slows down to reduce the amount of air passed through the unloader valve.

The pump functions the same for both types. So as long as the unloader valve and throttle control are not an integral part of the pump all you need to do is to mount the pump on your electric compressor.

 

[bsaint]

You also have to increase the pulley size for the motor. Is it a Emglo pump when DeWalt bought Emglo? if so you need a 4 - 5" pulley @ 1700 rpm motor.

 

[EOC_Jason]

Harbor Freight & Northern Tool both have replacement air compressor pumps for cheap. They aren't fancy but they work. That's just an option assuming you really don't want to cannibalize your gas compressor.

 

[piston farmer]

So the pump from the gas powered unit is a KU emglo/jenny/dewalt pump with a 10 and 3/8" flywheel.

The old pump was a B3800 with a 13 and 3/4" fly wheel

The electric motor is an A.O. Smith 3450 RPM 16 amp unit with a 5 and 1/2" pulley

The gas honda had a 4" pulley, from what i can find its max hp is acheived at 3450 rpm also.

So from what i can tell i need to get a smaller 4" pulley for my electric motor. otherwise i will be spinning the dewalt/ emglo pump faster than what it was originally setup to do. Or should i just run it with the 5.5" pulley, will spinning it faster affect either the pump or motor badly?

Does this sound right?

 

[EOC_Jason]

Well...

Old Gas Powered Pump Setup = 1,330 RPM (approx)
New Electric Pump Setup = 1,829 RPM (approx)

You will have to do some internet searching to see what the min/max RPM of that pump is. But 1,830 seems a pretty high to me.

Your problem is you are using a smaller flywheel (makes pump spin faster) and a larger motor pulley (also makes pump spin faster).

Can you interchange the flywheels and/or the pulleys? Just changing the flywheel will get you to 1,380 RPM.

 

[bsaint]

KU max rpm is 900(ish.) I can forward you the email from the company if you'd like. I dont know where the above guy did his math, but a 5.5" pulley on a 1725 motor will spin the pump at 914 rpm. I have a 4.5" pulley running at on a 4 pole motor driven at 65 hz which is about the same speed.

The Emglo is a really good pump, I think i'd only be concerned about motor current at max RPMS and keep the oil good in it. I've rebuilt many from people running them unlevel and dry.

 

[EOC_Jason]

He said both the gas & electric motors run at 3450 so that's what i used. The numbers seemed a little high as you don't often see an oil pump run past 1,000 RPM. Glad someone else had info to chime in with...

 

[piston farmer]

I bought a 4 inch pulley for the electric motor to match the one that was on the gas engine. it was $8 bucks at grainger in stock

 

[piston farmer]

I am happy to report that it is up and running great! and it is way more quiet now with the new pump. so total cost involved here:

$ 8 bucks for the pulley
$ 12 bucks for a new v-belt in the correct size
$ 2 bucks for a 1/8 inch brass flush plug