generator question

[Phillip Lautier]

hi, ihave a generator problem that needs solved fast. i rented a 5500 watt and tried to run a1.5 hp compressor and a 12" mitre saw (both ridgid). it performed poorly and i had the rental company replace it. theydid so with a 6500 and now i can run the compressor but the chop saw lugs. im definately sure the compressor is running better but i cant tell if its running wide open due to the noise. 7 1/4 cirular bogs a little but not near as bad as the chop. also, all testing was done with the machines plugged directly/solely to the unit.
any effort is gratefully appreciated~

[Bruce Volden]

First off I would make sure that the extension cord/s you are using are of adequate size. I don't know the length you're using but the farther the "run" the larger the gauge you need. Hopefully you're not using a 50' length of 14 gauge extension cord for the compressor as it will burn it up rapidly. Also if you can get by not running both tools at the same time I would think this would help out. The generator seems like it will be enough to handle both though??!!


Bruce

[Al Willits]

Might want to compare wattage of both tools to watts output of the generator, also if they rate the tools a full load amps or watts use that number.


Al

[Jim DeLaney]

...all testing was done with the machines plugged directly/solely to the unit. any effort is gratefully appreciated~


Odd. Either generator should have had ample power. The 5500 watt unit should be capable of 45 amps output, and the 6500 watt unit should handle 54 amps at full load.

Your compressor should only draw about 18 amps - may 30 (briefly) on startup. The saw is probably more like 10 ~12 amps. Either generator should have handled both tools simultaneously, with power to spare...

Is it possible the rental agency gave you two bad - ie, worn out - generators? If they've seen a lot of use, they could have bad (worn) brushes, or burnt out diodes (from previous overloading).

[Ralph Barhorst]

I have had some experience designing and testing generators. You will find that most generators are not rated accurately. I have yet to see a generator that can put out more than 500 watts per horsepower. It will only put out that much if the generator is designed properly and the engine is rated accurately.

Also, an air compressor requires an extreme amount of starting power. For instance, a compressor that requires 2,200 watts to run will require 8,200 watts to start. Only fairly large generators can handle this amount of starting power.

My best guess is that these generators are just too small.