[Rhodes22-list] genset test

Roger Pihlaja cen09402@centurytel.net
Wed, 6 Nov 2002 05:32:53 -0500


Rik, Brad,

The electricity is converted into microwave radiation inside the microwave
oven by a device called a magnetron.  The electicity/microwave conversion
efficiency is not 100%.  You are also correct in that there are other
parasitic losses from turntable motors, cooling fans, power supply
inefficiencies, etc.  60% overall efficiency wouldn't surprise me.

Many electronic devices are very sensitive to supplied voltage & frequency.
Your ceramic heater is the most insensitive sort of load you could have
applied.  An electrical heater will just suck up any input electrical power
& turn it into heat, the voltage or frequency doesn't matter.  If you want
your genset to output a reasonable facimile of 120 VAC, 60 hz commercial
power when running your 600 watt microwave oven, then you probably need
about a 1500 watt genset.

Brad, if your Honda genset is really as quiet as you say, then I guess
that's not so bad.  All I'm saying is that running a genset may not be the
unobtrusive activity you apparently believe it to be.  If you choose to
cruise in any sort of rural area, then the chances are that any backpackers
on shore, anyone beach camping in canoes or sea kayaks, lots of other
boaters, & riparian property owners will not appreciate hearing a running
genset, no matter how quiet you think it is.  They may not be able to stop
you from doing it, but it's just one more thing that gives boaters a bad
reputation.  As a lakeside property owner, I can tell you that I & my
neighbors don't appreciate any engine noises coming in from the lake in the
middle of the night when we're trying to sleep with the windows open.  If
you were to anchor off our beach & ran your genset all night, then we would
all be plenty pissed off at you by morning.  Lots of communities already
have laws on their books which prohibit running gensets & other engines
during "quiet hours".

Roger Pihlaja
S/V Dynamic Equilibrium

----- Original Message -----
From: "Rik Sandberg" <racerrik@rea-alp.com>
To: "The Rhodes 22 mail list" <rhodes22-list@rhodes22.org>
Sent: Tuesday, November 05, 2002 11:35 PM
Subject: Re: [Rhodes22-list] genset test


> Brad,
>
> The microwave we got is supposed to be 600 watts. This particular model is
> made by Sharp. It's meant to be used in a dormitory or efficiency type
> apartment. It is almost a perfect cube shape about 13 inches on a side. I
> don't know how the output rating (600 watts) relates to the input
> requirement. Obviously they are not the same. The tag on the back of the
> unit says it should draw 9 amps. Taken times the voltage (110) this would
> indicate a 990 watt draw. Far more than half again more than the 600 watt
> output. If you took the 600 watt output and divided by the voltage this
> unit should draw 5.45 amps, which should be easily within the capabilities
> of the honda 1000 watt generator. I guess there must be a fairly large
draw
> for the fans, turntable motor etc., that is not factored into the output
> rating.
>
> So, there you have it. A 600 watt nuker can draw as much as 1000 watts. I
> suppose the reason the heater works is that the 750 watt output is the
only
> thing power is used for in the heater. No other parasites.
>
> Don't know if there are any other microwaves out there that would be any
> different. I you find one, I'd sure like to hear about it. AND, read the
> spec tag, not the box. :-)
>
> Good luck,
> Rik
>
>
> At 06:52 PM 11/5/2002 -0800, you wrote:
> >Rik, what size microwave (wattage) did you try?  It
> >looks like the smallest is about 500-600 watts.  I
> >hooked up a 750 watt ceramic heater and the Honda
> >handled it no problem.  Earlier I mispoke about the
> >noise level, you and I both know how quiet the thing
> >is.  The actual db level at full-throttle is 57 db.
> >Normal conversation is at 60db.  Later in the week I'm
> >going to look for a small unit in the .6 cubic foot
> >range around the 600 watt level.  Looks like it should
> >work on paper.  Brad.
> >
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