I recently bought a Shop Vac 6000. It works quite well but I have a question
about the specification "6.0 peak horsepower".
The vacuum indicates that it uses 11.0 amperes. At a nominal 120 volts this
would mean 11x120 = 1320 watts.
The "horsepower", a non-SI unit, is defined as being exactly 746 watts (an SI
unit). A watt is a watt is a watt, of course, so it would seem to me that
1320/746 or approximately 1.77 hp is more accurate. (I have no idea what a
"peak" horsepower is. The watt is the standard unit of power; the horsepower
is an outmoded unit used only in the USA.) This assumes no losses within the
motor itself, of course; actual "hp" of output would be lower due to this.
A 6.0 hp motor would be huge, and would likely require a dedicated 240 volt,
30 ampere circuit. Further, due to the inefficiencies of single-phase motors
in large sizes, it would probably be polyphase.
Any explanation would be welcome, and interesting.
Carleton MacDonald
Gaithersburg, Maryland
