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#759 - 03/10/01 04:03 PM 4 HP Compressors  
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
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?


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

Work Gear for Electricians and the Trades

#760 - 03/10/01 04:15 PM Re: 4 HP Compressors  
silverbk  Offline
Member
Joined: Feb 2001
Posts: 60
Marketing.

You cannot get more energy out than you put in.


#761 - 03/10/01 04:28 PM Re: 4 HP Compressors  
Scott35  Offline

Broom Pusher and
Member
Joined: Oct 2000
Posts: 2,707
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 [Linked Image]

They could be Alien Technology! [Linked Image]

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 [Linked Image]

Or maybe, they should leave the crack pipe at home and lay off the Peyote, prior to going to work [Linked Image]
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


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

#762 - 03/10/01 07:12 PM Re: 4 HP Compressors  
Tom  Offline
Member
Joined: Jan 2001
Posts: 1,044
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


Few things are harder to put up with than the annoyance of a good example.

#763 - 03/10/01 07:30 PM Re: 4 HP Compressors  
Scott35  Offline

Broom Pusher and
Member
Joined: Oct 2000
Posts: 2,707
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 [Linked Image] ].

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!

#764 - 03/10/01 07:40 PM Re: 4 HP Compressors  
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,878
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? [Linked Image] Otherwise I've got no Idea how they could say that.

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

Bill


#765 - 03/10/01 07:52 PM Re: 4 HP Compressors  
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,878
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!! [Linked Image]

Bill


#766 - 03/10/01 09:25 PM Re: 4 HP Compressors  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,308
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...
[Linked Image]

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


#767 - 03/10/01 10:23 PM Re: 4 HP Compressors  
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
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

#768 - 03/11/01 03:20 PM Re: 4 HP Compressors  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,308
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??

[Linked Image]



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


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