Date: Sat, 09 Mar 2013 20:40:43 -0800
From: Bill Turner <dezrat1242@yahoo.com>
To: Amps <amps@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
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