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#759 - 03/10/01 12:03 PM 4 HP Compressors
sparky66wv Offline
Member

Registered: 11/17/00
Posts: 2339
Loc: West Virginia
My friend has purchased one of these new compressors that claim to have 4 HP. The compressor runs on 115V at 15A. All this data has been taken from the nameplate (The plug is 15A).

Imagine my surprise when I practically called him a liar and I said that you can't get much over two horsepower from 15 amps, and you're only allowed to load it to 80% which makes it even less...

What gives?
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Residential/Commercial Inspector
5 Star Inspections
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#760 - 03/10/01 12:15 PM Re: 4 HP Compressors
silverbk Offline
Member

Registered: 02/24/01
Posts: 61
Marketing.

You cannot get more energy out than you put in.

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#761 - 03/10/01 12:28 PM Re: 4 HP Compressors
Scott35 Offline

Broom Pusher and
Member

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
I would like to know where and how these manufacturers come up with these HP ratings!!

As far as I know, it's physically impossible to have anymore or anyless than 1 HP developed by electrical transduction, using 746 watts of power - AC or DC.

These motors however, defy the laws of physics, because they somehow create energy from thin air and use more energy than is possibly available

They could be Alien Technology!

It must be a HP figure using true power only, or rudimentry methods of calculating output power.

Maybe they're just trying [with some success] to yank the uninformed public's chain

Or maybe, they should leave the crack pipe at home and lay off the Peyote, prior to going to work
Oh, I can feel the flames rising now!!!!!!!

On the serious side, when [and if] someone gets to the bottom of this, PLEASE!! pass it my way!!

Scott SET
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Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

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#762 - 03/10/01 03:12 PM Re: 4 HP Compressors
Tom Offline
Member

Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA
It is all marketing hype. That is why the NEC recently made a change to allow using the nameplate amps instead of HP when dealing with these overblown claims.

By the way, the HP claims are likely to be true, the motor in question will develop 4hp, just before it lets all of it's smoke out, for sure it is not useable HP.

Tom
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#763 - 03/10/01 03:30 PM Re: 4 HP Compressors
Scott35 Offline

Broom Pusher and
Member

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
I can see it producing 4 HP at a seriously sharp peak in the power wave, and for such an instantainious amount of time, it just barely lasts long enough to be considered HP.
Actual, usable HP would most likely max out at a continuous load of like 1/3 or possibly 1/2 HP, if it's being pushed enough and someone sprays the overload with a fire extinguisher. Any more than that would for sure lock the rotor or trip the overload [W/O fire extinguisher's CO2 applied ].

I would like to see someone try to run a 4 horse pump from one of those motors! Boy, they would be mad! From the physical size, it looks like a 1/4 HP squirrel cage motor.
At around 40 PSI, the motor trips it's OL!

Scott SET
_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

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#764 - 03/10/01 03:40 PM Re: 4 HP Compressors
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
'66

Good Question!
I've been wondering that myself.
My Wet/Dry Vac says 5.0 HP (Peak) in Big Lettering. Could they be talking about the Inrush Current? Otherwise I've got no Idea how they could say that.

I've noticed similar odd ratings on regular Household vacuums.

Bill

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#765 - 03/10/01 03:52 PM Re: 4 HP Compressors
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
Hey, I just thought of something!

Maybe all the Electricity that gets "Lost" from other appliances gets sucked up by the Vacuums?? That must be it!!

Bill

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#766 - 03/10/01 05:25 PM Re: 4 HP Compressors
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
dunno if it applies, but have you ever gone shopping for stereo speakers? they advertise in watts, but the small print might say rms, peak, or peak to peak...


[This message has been edited by sparky (edited 03-10-2001).]

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#767 - 03/10/01 06:23 PM Re: 4 HP Compressors
sparky66wv Offline
Member

Registered: 11/17/00
Posts: 2339
Loc: West Virginia
My band has a 1000W PA, a 300W Monitor Amp, a 300W Bass amp, a 100W Guitar Amp, and several other peripherals like delays and reverb units that pull about 100W each.

But yet with ALL our devices plugged in and my trusty fluke meter measuring current, I see about 8 amps peak... This is with the signal on the board peaking...and loud enough to split atoms through resonance.

Another question (unrelated)... would speaker cable that is too small (16 gauge)cause an amp (300W per channel)and two woofers (300W each)to blow? This was in a 100' snake, so voltage drop and resistance may come into play here. (8 ohm speakers).
_________________________
-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

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#768 - 03/11/01 11:20 AM Re: 4 HP Compressors
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
well you might try the tv & stereo section of do-it-yourself-dot-com

http://forum.doityourself.com/forumdisplay.php?forumid=68

how does that circuit work anyway, board-effects loop-snake-crossovers-speaker??





[This message has been edited by sparky (edited 03-11-2001).]

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