Re: Generac pressure washer runs high rpm
I had to use a pulley & belt to couple the GM alternator to the engine,that also allowed it to be sped up so the engine does not have to be screaming at 3600 rpms to get more power from the alternator..a 4" pulley was all I had with a 7/8" keyed bore (not the most common size,some electric motors use 7/8" though,I found it on a junked electric motor at a salvage yard)...I used an old 37 amp alternator I had off one of my many old GM vehicles hanging around..
The alternator needs a 12V "feed" to excite it,and get it to charge--but as long as the battery your jumping with it has some voltage in it,it will kick in and start charging without needing an additional battery..
My original idea was to make a "weldernator",after seeing YouTube videos of alternators modified to be used as a welder..but the 37 amps wasn't enough to be of much use,so I decided to use it as a battery booster instead--you could also put a 110V inverter on it and use it as a generator,it is possible to get 110V DC from an alternator too quite easily,but only lights and some AC/DC motors can be run on DC..
I made a crude mount for the alternator using a stock bracket off a GM straight six and a hunk of 2x8 wood bolted to the pressure washer cart's legs,so far it has worked very well,I have had to put a new belt on it twice though,because a 1/2" "A" V-belt rides a bit high in the alternator pulley and it'll shred it in a few hours..
A 3/8" belt might work,if it doesn't sit in the bottom of the 4" engine pulley,I just used what belts I had hanging around,1/2" x 28"..I'm keeping my eyes peeled for a alternator with a 1/2" pulley sheave,they used those on medium duty trucks like C-60's..