Next message: Lee Haefele: "Re: lv-ab: Inverters... pure sine or modified?"
Brian Stewart wrote:
James
Interesting comments. I have a number of modified and one pure sine wave
inverter aboard. I'll run a number RF noise tests this weekend when we
get back aboard. May be the reason I still get a bit of noise at 14 MHz.
By the way the pure sine wave unit is the only way to power a computer
and speaker system if you plan on attaching a separate sound system to
it... It totally eliminates the hum that comes with using a modified
inverter.
--
Brian Stewart
Pilgrim
Whitby 42 #304
VB8320 VA3PIL
REPLY
While I was still employed at Xantrex, we ran some tests on 1000 watt
inverters, one MSW Prowatt and one Prosine.
The tests were conducted by some radio amateur operators with access to lab
quality spectrum analyzers and so one.
The amount of noise and RFI radiated by the Prowatt was terible.
It effectively cancelled low frequency communications on the marine SSB
bands over any distance.
Not to mention a lot of ham bands. Weak signals were simply drowened out.
For those who do not use ham radio, remember that Differential GPS also
relies on a low frequency broadcast channel.
And if you still like ot use Loran, the 100Khz carrier really ges clobbered.
And then of course you have all those other electronic toys that are
sensitive to harmonics generated by quasi sine wave inverters. The amountof
harmonics is proportional to how sharp the rise time is.
Sharper ( faster ) rise time of the waveform means more harmonics.
This is why MSW inverters cause induction motors to run hotter than normal
and thus shorten their service life.
But if you change appliances every few yeas who cares!
Cheers
Arild
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.735 / Virus Database: 489 - Release Date: 8/6/2004
___________________________________________________________________________
|| The Live-Aboard List : send a "subscribe" or "unsubscribe" request ||
|| in body of message to: ||
