Sharp Microwave

[Diplomat Don]

I have no proof of this, but I believe the Sharp Microwave/Convection ovens in most of our coaches don't like to be powered by the inverter.

I've found that my unit sounds noticeably different when running on the inverter or even just sitting there idle while the inverter is on. I added a small paddle switch (WalMart) that plugs into the outlet and then the microwave cord plugs into the switch. I leave the microwave off when we're not hooked to shore power. If I need to use the microwave while on the generator or inverter, I flip the switch and turn it off when done.

I've read a lot of treads about the problems people have with these and I just don't think they like the power they see from the converter. Not scientific, but food for thought. Ours is three and half years old with no issues. Maybe this will add some longevity to someone else's unit.

[Diplomat Don]

I have no proof of this, but I believe the Sharp Microwave/Convection ovens in most of our coaches don't like to be powered by the inverter.

I've found that my unit sounds noticeably different when running on the inverter or even just sitting there idle while the inverter is on. I added a small paddle switch (WalMart) that plugs into the outlet and then the microwave cord plugs into the switch. I leave the microwave off when we're not hooked to shore power. If I need to use the microwave while on the generator or inverter, I flip the switch and turn it off when done.

I've read a lot of treads about the problems people have with these and I just don't think they like the power they see from the converter. Not scientific, but food for thought. Ours is three and half years old with no issues. Maybe this will add some longevity to someone else's unit.

[MonacoMama]

Hmmmmm-Diplomat Don...when did you add this switch and of course I am sure there is NOT a picture of said switch in your photo album, is there?

Sacs & I agree with the statement of the microwave not performing well on the inverter. I also know that some literature that came with coach states not to use the microwave for a prolonged period of time on the inverter. (It was decided that we would not use the microwave on the inverter for more than a minute after reading that.)

Thanks for the tip...

MM

[Drifter]

We need a picture and description of the paddle switch. We have been unplugging it, and a switch would be great. I can't believe that I have been unplugging it and not thinking of adding a switch.(DUH)

[MonacoMama]

Dip Don...
Are you talking about something like this??




MM

[Route 66]

It's the modified sine wave inverter that many of us have that cause the microwave to sound differently.

Shore power, generator power, and pure sine wave inverters do not cause a problem.

[SacsTC]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Route 66:
It's the modified sine wave inverter that many of us have that cause the microwave to sound differently.

Shore power, generator power, and pure sine wave inverters do not cause a problem. </div></BLOCKQUOTE>
Very true Dirk, but until this inverter gives it up, I will not be putting out the approx $1800 to upgrade to True Sine Wave. I have however, been thinking about putting in a breaker and a new line to the Kitchen plugs that power the Microwave.
Don's idea is much simpler, but MM is a gadget freak and needs lots of power up front for the Entertainment center.

[bullydogs1]

We used ours on the inverter once and definitely noticed a difference...not only the sound but the quickness of cooking to warm up something....

I can understand this and wouldn't use the microwave for more than a minute anyway on the inverter....at least I know I'm not the only one who hears things differently

[Route 66]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Very true Dirk, but until this inverter gives it up, I will not be putting out the approx $1800 to upgrade to True Sine Wave. </div></BLOCKQUOTE>

Me either.

[Diplomat Don]

The switch is a white block (three prong) that plugs into a standard outlet. You can then plug a three prong cord (such as the microwave cord) into the switch. On the side of the switch is a 1" x 1" paddle to turn it on and off. The whole thing is maybe an 1.5" x 1.5" square and 1" thick.

Many stores sell these, but most are two prong (no ground). Surprisingly, WalMart is the only place that I could find that sells the three prong. I located it in the hardware department where they have cords, outlets and other electrical stuff.

[Sixpack98]

Don,
I found a 3 prong paddle at Lowe's and your idea is a good one. I don't think a modified sine wave will hurt a microwave, they use a similar setup for upconverting to a higher voltage. I use the paddle switches for Christmas lights.

[SacsTC]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I don't think a modified sine wave will hurt a microwave, they use a similar setup for upconverting to a higher voltage </div></BLOCKQUOTE>
I don't know if it will harm it or not, but I agree with DDon. Mine sounds like it is really hurting when running strictly from inverter and we will not do it again.

[glennb100]

A typical full size microwave oven is a real power hog. If its rated at 1800 watts, that's 15 amps of 120V AC power. That translates into more than 150 amps of 12V power that your house batteries have to provide to the inverter so it can power the microwave. I suspect that the reasons that the microwave sounds different are not only the modified sine wave output from your inverter, but, more importantly, the fact that the house batteries can not sustain a 150 amp load at 12 volts for very long.

Best advice - only use the microwave when plugged into shore power, or with the generator running.

[Jim Stewart]

I believe that particular model Sharp R-1870 (different last number mean a different color than black) is a 850 watt max. That would be approximately 7 Amps. That coupled with anything else running through the inverter when not connected to shore power does pull down the available load. On that microwave, I believe there is a damper motor that turns on every 59 seconds to check that it is working and then shuts off. When that motor turns on it creates a momentary draw that makes the thing groan!

Several people have reported and I had the problem that Sharp made bad motors for a long time in that unit. You can tell you have the problem when the unit runs 59 seconds in any mode and then shuts itself off!