I just bought this shopvac. It claims 5.75hp. Hmmm... Let's do some math. 5.75*746= 4300W. 4300W/120V= 36A. So this thing should only be able to work on a 40A breaker. But what 120V load is on a 40A breaker? And what does a 120V 40A outlet look like? The shopvac's cord plug has a regular 15A pinout. I'm thinking this thing is over rated by a factor of 4 at minimum. I couldn't get it to trip a 10A breaker no matter what I tried. Grossly false advertising.
Of course I'm ignoring the elephant in the room; There is the work "peak" there. So I get it, that's not constant running HP. But still, it obviously never "peaks" in any mode of operation or else the breaker would trip. So are they taking inrush current, multiply by (120V/746W), and calling that "peak HP?" That's a completely meaningless number!
Now, further damning this claim, are they talking input power or output power? I figured they were talking electrical HP (input power) but if they're talking mechanical output power, that's even worse. I'm going to plug this thing into my killawatt and see how much power it actually draws. When I search for "universal motor efficiency" I am seeing estimates between 55% and 70%. I'll call it 55%. We'll see how much output power this thing ACTUALLY has.
Of course I'm ignoring the elephant in the room; There is the work "peak" there. So I get it, that's not constant running HP. But still, it obviously never "peaks" in any mode of operation or else the breaker would trip. So are they taking inrush current, multiply by (120V/746W), and calling that "peak HP?" That's a completely meaningless number!
Now, further damning this claim, are they talking input power or output power? I figured they were talking electrical HP (input power) but if they're talking mechanical output power, that's even worse. I'm going to plug this thing into my killawatt and see how much power it actually draws. When I search for "universal motor efficiency" I am seeing estimates between 55% and 70%. I'll call it 55%. We'll see how much output power this thing ACTUALLY has.