Hello,
Let's say I have a 5-hp compressor package, 240-VAC 1-ph motor, typical setup.
If I install a second identical motor with its own separate breaker and power feed,
and hook the two motors together with a pulley-and-belt connection, what have I accomplished ?
I still have the same tank and compressor, so my max pressure is the same.
Do I have twice the duty cycle at any CFM draw ?
Do I have twice the CFM capacity, i.e., I can run 40 CFM @90psi instead of 20 CFM @ 90psi ?
What are some other ramifications of this mod ? Shorter compressor service life ?
Thanks much for your insight !

Just passing by this forum. And thought I would reply....
<<<what have I accomplished ?>>>
A learning experience on adding a second motor.

<<<I still have the same tank and compressor, so my max pressure is the same.>>>   Yes

<<<Do I have twice the duty cycle at any CFM draw ?>>>  Duty cycle of the motors are usually 100% so that would not change.

<<<Do I have twice the CFM capacity, i.e., I can run 40 CFM @90psi instead of 20 CFM @ 90psi >>>
The only way to get twice the CFM is to spin the pump twice as fast. 2 motors would not do that. But pumps are rated for a certain speed. Exceeding that will shorten its lifespan. Doubling the speed to get twice the cfm will dramatically shorten its life. Maybe down to minutes??? Especially if it is near maximum now.

<<<What are some other ramifications of this mod ? Shorter compressor service life ?>>> Nothing much different. Only thing that would change is the load on the 1st motor would be cut in half. Compressor running at same speed would not notice any difference.

Put it this way. Changing a 4 cylinder in a car to an 8 cylinder will not make it drive any different at 55 MPH. A larger motor or adding a second motor will increase the start up speed. But start up speed in a compressor is only a second or so. Just like a 4 cylinder to v8 swap would increase the start up speed. But once running there would not be any noticeable difference.