I have to ask, how do you power your polisher and vacuum? If you really need a generator for working at sites with no power availability I can offer a few suggestions in general.
1. Record on paper, the voltage, the amperage and/or the wattage of everything that you will be using that is powered by electricity and add them all up for a total of amps
or watts.
Wattage as a measurement of electric usage is voltage x amperage so if you have a tool that does not list the amperage but does list the wattage, simply divide the wattage by the voltage to get your amperage rating.
An example would be if you had a 1000 watt halogen light and needed to know the amperage, you would divide 1000 watts by 120 volts which equals 8.3 amps.
2. Figure out what tools you could possibly be running at the same time such as lights and polisher or 2 lights and a vacuum. Will you have a helper doing interiors while you are polishing paint? If so and you're working at night, you'll need your total amperage draw (how many amps you'll be using at any given time)
Let's say you have a helper and you are working at night with two 1000 watt halogen lights, a 12 amp rotary polisher and a 10 amp shop vac.
The two 1000 watt lights = 2000 watts/120 volts=16.6 amps. Plus your 12 amp rotary and your 10 amp vacuum. There you're possibly (at full load) drawing 38.6 amps continuous. Everything you're running is 120 volts so multiply 38.6 amps by 120 volts to get a total of 4640 watts of continuous electricity usage. You would want to purchase a generator that can power a 5000 watt load continuously.
Be mindful that a lot of generator/inverter manufacturers use the peak load handling numbers on their boxes and generator decals for marketing purposes so be sure to look at the continuous power handling numbers and not what is printed in large print on the box or the generator decals. Instead, look on the metal plate located on the actual generator part of the generator like in the picture below.
If I were going to be consuming 4640watts at any given time I would probably want a generator that would be able to handle 6000 watts continuously so that I wouldn't putting the max load on my generator all the time causing premature stator or rotor winding failure.
Regardless if it's just a polisher or an air compressor, your generator needs to be able to handle the current (amps) that the load will demand on a continuous basis, so if you will be using just an air compressor and nothing else and the compressor requires 20 amps to run under load you'd multiply 20 amps x 120 volts = 2400 watts + some room so you won't be over taxing the generator, I'd say a 5000 watt peak generator which would likely produce 3500 watts continuous.
There is also the the hertz to think about. hertz = electrical cycles per second. Most power tools run on 60 hertz. Most generators generate at 50-60 hertz depending on load cycles. (turning stuff on and off that slow down and speed up the gasoline engine during use)
Running a 60 hertz power tool at a constant fluctuation between 50 and 60 hertz is not necessarily good for the tool and could cause the tool to have a shortened service life. Exactly what happens here that is bad for the tool is beyond my level of knowledge so if there are any electrical engineers here maybe they could explain it.
That's the best I can give you on the subject, Hope it helps. TD
