Microwave and Inverter don't play together well

[CapnCrunch]

Hey y'all. I just recently got around to putting a microwave on my sailboat and tested it while running on my Heart (Xantrex) 2500 inverter. The results were not good. The microwave ran but it made a loud humming noise and you could smell electronics burning, so I shut it off after about 10 seconds. With further reading, I believe it to be a pure-vs-modified sine wave issue. What I cant seem to find is info on which type of inverter mine is and, since I prolly need to buy a new microwave, how to determine which one will work with my inverter.

Any help will be greatly appreciated.

[sailorboy1]

If the new microwave wouldn’t work on your inverter, probably none will. I replaced my inverter recently and got a pure sine wave unit just so the the microwave would work.

But before you replace either you should try a different power source for the microwave to see it it works.

[danielamartindm]

Perhaps I've been misled, but I was under the impression that microwaves really require a genny.

[CapnCrunch]

Originally Posted by sailorboy1

If the new microwave wouldn’t work on your inverter, probably none will. I replaced my inverter recently and got a pure sine wave unit just so the the microwave would work.

But before you replace either you should try a different power source for the microwave to see it it works.

The microwave is about 5 years old and I have used it on shore power just a few minutes ago. Next step will be to try it on the genny.

[sailorboy1]

Originally Posted by CapnCrunch

The microwave is about 5 years old and I have used it on shore power just a few minutes ago. Next step will be to try it on the genny.

There it surely is the inverter. My old modified wave inverter, a Freedom 20, said right in the manual t wouldn’t run a microwave. But it did once in a while before I finally caught on.

My new pure sine inverter runs anything within its power rating and puts out better power than my generator.

[Stu Jackson]

My Heart Freedom 15 is a modified sine wave unit, purchased in 1999. Xantrex bought Heart out shortly thereafter, but IIRC all Freedoms were modified sine waves. Manuals are available for older units on Xantrex's website. Ours runs a small, almost mini-microwave that was installed by the PO in the late 80s or early 90s, and they play well together. Could be that newer and/or bigger microwaves require pure sine wave, although in my readings there hasn't seemed to be a mandate --- seems some do, some don't.

[gbr]

Originally Posted by danielamartindm

Perhaps I've been misled, but I was under the impression that microwaves really require a genny.

You have been misled. I run ours using our Victron Inverters all the time.

OP: You will almost certainly need a pure sine wave inverter for any microwave. Also, some coffee makers need pure sine wave as well. A lot of things with electric motors (depending on type) - need pure sine wave.

Might be an expensive proposition to replace your current inverter, but that is what I would do if you want a Microwave and not start your genny.

[Wayfarer1008]

The cheaper and older inverters produced a square wave signal that gave you power for charging batteries but was not compatible with most household appliances and computer systems. What you need "as most people pointed out" is a pure sine wave inverter.

[Locquatious]

We ran an old microwave for years off the inverter. It took lots of power and was tough on the batteries so we did not run it for long periods. Consider a low power microwave.
At home we had a low power microwave that ran fine on a 3KW gen. We replaced the microwave with a mid power unit. Now the fan in the microwave does not work during operation on the gen. We have to turn all other services on the microwave connected circuit side off to even get that performance.

[Jdege]

Most electronic devices use DC internally. They run AC through a transformer, then a rectifier, then a voltage regulator, to get a clean DC input.

Which is why it always odd, to me, to run then off an inverter.

Are microwaves different? Does the magnetron require AC?

[Stu Jackson]

Originally Posted by Wayfarer1008

The cheaper and older inverters produced a square wave signal that gave you power for charging batteries but was not compatible with most household appliances and computer systems. What you need "as most people pointed out" is a pure sine wave inverter.

Could you please explain inverters charging batteries? That one got right by me....

[donradcliffe]

I used to run a Sharp microwave on my Freedom inverter. It took a little longer to heat things on the inverter, but it worked. The modified sine wave inverter also played nice with tools, TV's, breadmakers, and everything else I plugged into it.

[DennisRyan]

Could be not enough amps supplied to the microwave. Try running your engine and then running the microwave off the inverter.
I had this issue with running a small hookah compressor off of my inverter. Once I turned on the engine, the problem went away.

[Cheechako]

My older Heart Interface Inverter/chargers worked well with a microwave.... and other ac appliances. I think I had them on 3 boats. Not sure how that helps, they were 80's -90's units. Microwaves are a huge draw though, I didn't have 1100 watters , had smaller units.

[a64pilot]

Originally Posted by danielamartindm

Perhaps I've been misled, but I was under the impression that microwaves really require a genny.

If you have enough bank and a large enough inverter, you can run anything.
I don’t have a microwave, but assume my 2800 W inverter would run one, and my bank tolerate it for short durations, etc 3 min or so.
Past that and it would probably be better to have a generator on.