Just 'cuz I'm feeling electronical at the moment, one time on osme scientific teevee show, I saw an AC ammeter in series with a typical vacuum cleaner. I think this was the series-wound type, but it still vividly illustrates the point. They plugged the air inlet, and it whirred up, as vacuums do - oh, heck, come on - we've all done that! Put your hand over the vac hose, and its pitch rises, like it's really, really struggling. Well, the ammeter dropped to about 20% of what it was while just sucking air. There was no air to move, all the motor had to overcome was friction, the air just spun around, and the motor almost freewheeled!
This was, however, involved in the great Kirby vs Electrolux debate. In Kirby salesman school, they told me about the Kirby vs. Electrolux thing - the Electrolux lovers love their Electrolux because it's a cannister. All of the motor's power is applied to suction. The Kirby, however, was an upright, and although built like a f***in' tank, all of the air _AND_ dirt went through its impeller, and depended on the residual pressure from the impeller to put the dirt up into the bag.
But it had an ass-end impeller - there was one impeller for moving air and dirt and trying to suck it up from the carpet and blow it upwards into the dirt bag simultaneously - but motor cooling air didn't go through that air path. The ass-end air cooler impeller just blew air from the cooling holes through the motor's windings, and out wherever, I think maybe even another set of cooling vents.
So you could plug up a Kirby, and it'd whine like an animal in pain, as vacuums are wont to do when there's no air to move, and the Kirby's motor wouldn't care in the least, because it has its own ventilation thingie.
So, the sales trainer says, "Offer to do the test. Tape the two hoses together, let the Electrolux out-suck the Kirby, collapse its bag, and then just leave them like that until one of them burns out."
Lately, though, I've seen an upright with the same kind of air path as a canister - the motor evacuates the space in the bag place, and air rushes through the hose, or directly up the carpet thing, and gets pulled into the bag, and lately, they've got the dirt path go to the top of the dirt bag.
Holy crap, ame I fupped duck or wha?
Thanks! Rich
Any questions, just ping Rich, You Asshole! ;-D %-} ;-D