Thread: generator query

don't forget you'll also likely be running lights, radio (or other soothing noise maker), probably an air cleaner and/or a dust collector (or shop vac) as well as the power tool

From what little I know, because your load will be intermitant, a petrol genny is better than a diesel one (the cylinders in a diesel motor apparently glaze if the motor doesn't run long term at about 70–80% full load)

also allow for some expansion in yupur power tool collection!

First point, your Bosch router is 1100 Watts, not 1100 KW. Doesn't affect the reasoning that you have made, but it will avoid some of the stunned looks when you start shopping. The substation in my street serves about 200 homes and is rated a lot lower than 1100 KW, so seeking an 1100 KW alternator would really get a salesmans heart moving.

Typically, a motor starting from stationary without a load (drill, router etc) will draw 4 to 6 times its running current for maybe a second until it gets up to speed. A partly loaded motor as per a belt drive saw, jointer, drill press etc will draw more, and a loaded motor working a compressor, fridge etc will draw even more, maybe 10 times its rated operationg power.

However to counter this, and as something that many overlook, the power rating of a motor is a thermal thing, rather than an absolute. You would probably find that your routers' operating power (the power required to spin the motor and a bit at the rated speed without inserting the bit into a workpiece) is probably in the order of about 400W or 1/3rd of the rated power of the unit. Start the tool into a light cut and the power consumption will increase accordingly, and continue to increase in proportion to the amount of work you extract from the unit.

Once you load the unit up to the 1100 W level, you reach a point where the heat generated within the tool motor is at the limit of the unit's cooling system. You can load the unit further and increase it's power consumption beyond that point, but run the risk of having the tool overheat and cause permanent damage if the load is maintained for more than a few seconds during a minute or so of running time.

For this reason, I would argue that for the router, an alternator with a true continuous rating of of 2500 W and a peak rating of 2800 to 3000 W (for 1 to 2 seconds) should safely start the router unloaded, and provide sufficient power for the router to be loaded to its rating in use, plus run a couple of lights. However, if you might wish to include a similar rated shop vac for later clean up, then the 3500 W continuous range would be more suitable for starting that unit as it cannot be unloaded for starting. To start and run the router and a vac as a dust extractor simultaneously would require a substantially higher alternator rating.

Hope this makes sense for you.

thanks for the replies. I obviously don't know much about power....

Now I just have to find a genny that won't make my wallet explode - preferably costing dollars rather than kilodollars...

Thanks again for the information