Inverter to drive microwave
cnctut
it off a square wave inverter when camping? Is there any real
difference between "square wave" and "modified square wave" inverters?
Thanks
Tut
Dave Plowman (News)
You're into a fairly chunky invertor to power a decent microwave. And a
chunky battery to power it. Surely a gas or paraffin stove is much more
suitable for camping?
--
*Always borrow money from pessimists - they don't expect it back *
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
cnctut
The microwave is in an RV--I have multiple generators that would
work--just hate to start them for 2 minute popcorn or 60 sec hot tea.
Thought an inverter might be a quick solution--the RV has 2 D-8
batteries for DC power--1350 amp-hrs each.
Thanks
Tut
Funfly3
"cnctut" <cnctu...@wmconnect.com> wrote in message
news:1115852660.9...@g14g2000cwa.googlegroups.com...
better for a microwave
Jim Yanik
news:1115834384.0...@o13g2000cwo.googlegroups.com:
Iron-core transformers do not like square waves-the harmonics just generate
excess heat in the core.You would need a hefty inverter to power the
average MW oven;they run about a kilowatt output(~15A@120VAC input),and
with an iron-core transformer,the startup surge would require more inverter
power.
"modified squarewave" inverters generate a stepped version of a sine
wave,reducing the harmonic output.
--
Jim Yanik
jyanik
at
kua.net
NSM
"Jim Yanik" <jya...@abuse.gov.> wrote in message
news:Xns9653C9AF41F...@129.250.170.84...
> "cnctut" <cnctu...@wmconnect.com> wrote in
> news:1115834384.0...@o13g2000cwo.googlegroups.com:
>
> > Any reliability issues concerning a new Sharp R-1540 microwave to power
> > it off a square wave inverter when camping? Is there any real
> > difference between "square wave" and "modified square wave" inverters?
> Iron-core transformers do not like square waves-the harmonics just
generate
> excess heat in the core.You would need a hefty inverter to power the
> average MW oven;they run about a kilowatt output(~15A@120VAC input),and
> with an iron-core transformer,the startup surge would require more
inverter
> power.
>
> "modified squarewave" inverters generate a stepped version of a sine
> wave,reducing the harmonic output.
An inverter microwave might work better since they rectify AC to DC.
--
N
NSM
> NSM--isn't there some 120vac in the microwave unit somewhere--AC fans,
> motors, etc?
Sure, but they're shaded pole motors - should be OK.
--
N
Joel Kolstad
> Thanks--I got off my lazy kester and did a google and found the wave
> shape for a modified square wave inverter. Appreciate your input.
A modified sine wave doesn't have a 3rd harmonic, and the idea is that
eliminating is goes a long way towards reducing overheating in transformers
(since the higher the harmonic, the more it's naturally surpressed from the
core's self inductance).
---Joel Kolstad
Jim Yanik
news:1115859563.8...@g44g2000cwa.googlegroups.com:
>
> Jim Yanik wrote:
>> "cnctut" <cnctu...@wmconnect.com> wrote in
>> news:1115834384.0...@o13g2000cwo.googlegroups.com:
>>
>> > Any reliability issues concerning a new Sharp R-1540 microwave to
> power
>> > it off a square wave inverter when camping? Is there any real
>> > difference between "square wave" and "modified square wave"
> inverters?
>> >
>> > Thanks
>> >
>> > Tut
>> >
>>
>> Iron-core transformers do not like square waves-the harmonics just
> generate
>> excess heat in the core.You would need a hefty inverter to power the
>> average MW oven;they run about a kilowatt output(~15A@120VAC
> input),and
>> with an iron-core transformer,the startup surge would require more
> inverter
>> power.
>
> I'm ok with a little bigger inverter if you think the extra heat for
> the microwave transformer won't be a problem over one 2 or 3 minute
> duty cycle.
>
>
>>
>> "modified squarewave" inverters generate a stepped version of a sine
>> wave,reducing the harmonic output.
>
> Are you saying a modified square wave inverter has multiple stair steps
> to max voltage vice one large step for older pure square wave
> inverters?
Yes,AFAIK.
cnctut
Thanks for the response--and thanks for not reprinting the Fourier
stuff. ;-))
Tut
Keith Jewell
of a microwave:
http://www.donrowe.com/inverters/inverter_faq.html
Unfortunately it's rather light on details. Anyway, it should work, but
you'll probably need a 2k running, 5k surge inverter to run it. They
are out there and actually not terribly expensive any more. Sinewave
units at that size are still pricey. A Xantrax 1750 for instance is
around $300 with the cable necessary to install it, and will run most
reasonably sized microwave ovens for as long as your batteries hold
out.
-Keith
cnctut
Tut
James Sweet
I have a 1500W inverter I've been trying to sell for $75 for a while now so
they're obviously not hard or expensive to acquire. It runs a microwave just
fine, transformer buzzes a bit louder but how often does one get run for
more than a few minutes?
NSM
"James Sweet" <james...@hotmail.com> wrote in message
news:0nDhe.6622$Y12.5595@trnddc09...
> I have a 1500W inverter I've been trying to sell for $75 for a while now
so
> they're obviously not hard or expensive to acquire. It runs a microwave
just
> fine, transformer buzzes a bit louder but how often does one get run for
> more than a few minutes?
And it's not impossible to smooth the output either.
--
N