[Amps] rms Volts, Amps and Watts

[Jim Thomson]

Date: Sat, 09 Mar 2013 20:40:43 -0800
From: Bill Turner <dezrat1242 at yahoo.com>
To: Amps <amps at contesting.com>
Subject: Re: [Amps] rms Volts, Amps and Watts

ORIGINAL MESSAGE: 
On Sat, 9 Mar 2013 20:02:45 -0500, Carl wrote:

>RMS Watts is in the same silly season class as Sears and some others "Peak 
>Horsepower" rating of electrical motors.

REPLY: 
Nothing wrong with rating peak horsepower in the sense of power for a brief
period. Kind of like ICAS rating vs CCS rating. 

Whether they do it accurately or not is another issue. I have no idea and
don't much care. 

73, Bill W6WRT

##  How the hell can u possibly run a 5  peak  hp motor on a 120 v outlet... u can’t.

##  a  real  5 hp motor, run on 208 v  3 phase power weighs 235 lbs, not 28 lbs. 
Most motors are 65% eff, not 100% eff.  5 hp = 5738 VA.  

##  I have measured a lot of AC motors, and most will have a start up current of triple
the running current.   Eng makers will use this start up current  to develop their bs
peak hp claims. 

##  ant rotator  makers like prosistel make ludicrous claims in their specs of  start up TQ...
which might last all of 1-2 secs max.   Meanwhile the actual running TQ is WAY less.  

##  The rms watts regs form years gone by for stereo gear were all based on 100%  duty cycle.
  25 watts rms, continuous, per channel, both channels driven simultaneously...into a XXX ohm  dummy load. 
That same 25 watt CCS could do triple or quadruple if expressed as IPP,  int peal power.   Then we had
IHF watts, EIA watts, and 4 more versions.   All were variations of ICAS and IVS. 

##  govt said enough is enough, and they are all rated in CCS.  Great idea really, they should do the same with
ham gear. 

Jim  VE7RF