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Are you saying over or underreving the compressor isn't a concern?
Compressor conversion question
- Thread starter dogfix
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pescador775
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The compressor was originally driven by a 3600 rpm engine. What possible harm would be done by using a 3450 rpm motor? It is normal practice to run an electric powered pump a bit slower anyway.
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Gotchya
I didn't have a clue about the gas engine RPM. I agree a slightly lower speed on this relatively high rpm unit would probably be a good thing.
I didn't have a clue about the gas engine RPM. I agree a slightly lower speed on this relatively high rpm unit would probably be a good thing.
pescador775
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The Alkin will work with 4-5.5 hp. The Airetex motor is the Honda GX, 5.5hp. Virtually all the small engines have a common bolt pattern for mounting purposes so that is rarely an issue. Some of you guys don't get it. The manufacturers aren't about to supply pumps with different sized pulleys, and the vendors sure don't want that. The motors and engines have to match whatever the stock pump is fitted with. That means motors and engines will have similar rev rates.
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An unloader takes the "load" off the compressor at startup by opening all the vavles so that no air is acutally compressed untill the compressor has roatated for a little while.
pescador775
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The Davey MC-1, etc has an unloader. My homemade 4 cfm portables are equipped with a clutch for the belt drive. The clutch consists of a steel boss which has been drilled, tapped and fitted with large knob. A bearing is pressed onto the boss and when the clutch is installed into its track in the compressor frame the belt presses against the bearing. When starting the engine, the clutch is in the lowered position. When the engine is firing good, the knob is loosened and the clutch is raised to tension the belt and is fixed in that position while operating the compressor.
pescador775
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Compressors require a substantial torque to get things rotating, and some smaller engines can get bogged down trying to start up a compressor even with all drains open. The 4 cfm Kidde needs about a 6 hp engine to make for a reliable start "in gear". However, with the clutch, the Kidde portable can use the low profile, light weight Briggs 5 hp. Those engines are not EPA friendly and no longer made. Lately, guys have been using the 5.5 Honda for most of the small machines and this is understandable. Right now, I'm working on a direct drive application which will use the 6 hp Kohler. With a six quart tank, this engine should run all day without topping up. Technical issues are several but one interesting problem is reversing the rotation of the Kidde block and this requires modifications to the oil pump, piping and fitting a CCW rotation fan.
Hey I just got a sw 4 cfm, and took it apart. My question is I want to use an electric motor-- can I do a direct drive? The shaft that the gas continetal engine has is strange--tapered and female thread. Do I have to be concerned about introducing axial loads if I use a pully system. Thanks
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