To avoid these ads, REGISTER NOW!

Something ain't right here.

TimDaToolMan

Banned
Joined
Mar 14, 2013
Messages
536
I went shopping and bought a new shop vac, my old one was 20 years old and bit the dust.

I noticed it says "6.5 peak HP" on the side of it. This is not some off-brand,it's an actual shop vac brand shop vac.

This means that it would pull 6.5 HP before the motor stops.

1 HP is 746 watts.

This means before stopping, it would pull 4,489 watts.

4,489 watts is about 40 amps.

Not only would the cord not handle that kind of current, the breaker would trip LONG before 40 amps could be obtained.

So either shop vac is lying, or my math is way, way off.
 
To avoid these ads, REGISTER NOW!

KF5LCH

Well-known member
Joined
Nov 10, 2011
Messages
216
Location
S.E. Oklahoma
Interesting, but we all know that motor will never make 6.5 HP. Not even on a good day in the test lab. Witchcraft I say!

Ohm's Law: 4,489 watts divided by 120 volts = 37.4 amps.
 

Abeo

Well-known member
Joined
Oct 22, 2009
Messages
784
Location
Calgary, Ab
it's "Peak" HP

Which is the HP caused by the amperage draw when you suddenly stop the motor, before the breaker pops. Useless number.
 

sasquatch12

Well-known member
Joined
Nov 6, 2013
Messages
403
Those ads and markings on this stuff are the BIGGEST FRAUD going!! What a bunch of ****, designed for people who think they're getting this HUGE powerfull motor.
People never read the ampreage draw, see this a lot now especially on bench grinders etc. Label states 3/4HP, but check the amps, and it's ONLY like 3.2 or something.
 
To avoid these ads, REGISTER NOW!

Mr_fixit

Well-known member
Joined
May 24, 2008
Messages
1,221
Location
Rustylvania
That's the current it uses a split second before it locks up. Yes, compressor ratings and shop vac ratings are ****....
 

sweetcretin

Well-known member
Joined
Oct 3, 2013
Messages
45
Location
Fargo, ND
A 20 amp breaker will source 40 amps for much longer than you think it will. If following the NEC, a 20 amp break can source twice its rated amperage for over a minute before it blows. (This is a traditional breaker. AFCI and GFCI have different behavior.) See page 26 and 27 of this document.

Vaccum HP ratings are still fiction.
 

neophyte

Well-known member
Joined
Apr 23, 2012
Messages
9,585
Location
Pennsylvannia
From what I understand, one of the major brands started rating their shop vacs using this system way back when, and then the other major brands followed the first brands lead so their vacuums wouldn't seem underpowered. I'm not sure which brand started the trend, but it was mentioned in one of the woodworking magazines.
 

Chuck122

Well-known member
Joined
Feb 17, 2013
Messages
490
Location
Québec, Canada
A 20 amp breaker will source 40 amps for much longer than you think it will. If following the NEC, a 20 amp break can source twice its rated amperage for over a minute before it blows. (This is a traditional breaker. AFCI and GFCI have different behavior.) See page 26 and 27 of this document.

Vaccum HP ratings are still fiction.

I just learned more than I ever wanted to know about breakers. pretty interesting
 
To avoid these ads, REGISTER NOW!
Top Bottom