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post #11 of 12 Old 10-23-2012
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Re: Microwave and gen.

When circuiting a home we use a rule of thumb: the full load on that circuit should not exceed 80% of the breaker rating. A 15 amp breaker should have no more than 12 amps of load. A load is anything that draws (consumes) electrical power. Volts x Amps = Watts

Your generator is rated at 1000 watts. Your microwave is rated at 700 watts (if you got that figure off the stamped plate or load label on the unit). Therefore your load is 70% of the rated load of the generator. You should be just fine.

If your generator has a breaker on it, check to see if it's rated at 7.5 amps or more. Your 700 watt micro should draw a little less than 6 amps at full power. If so, you are okay to zap away.
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post #12 of 12 Old 10-23-2012
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Re: Microwave and gen.

The 700W microwave probably uses at least 1150W and maybe 1400VA (11.7 amps). The generator is probably as small as they could make it with a rating of 1000VA (8.3 amps). If the 1000W generator breaker is 10 amps then you have 1200VA available but that's still not quite enough.

If the nameplate rating is in amps then you can multiply by 120 to get VA. If it says Watts then it is probably VA but you can't be sure. You might be able to use a 600W microwave if it is a high efficiency one that has less current draw than your alternator breaker. More likely the 600W one uses like 1100W and 1400VA.

Just get a 1200W or 1500W generator and make sure the alternator VA rating is somewhat higher. As long as you don't exceed the VA rating you won't trip the breaker or overload the alternator and the worst you could do is drag the engine down below 3600 RPM. Actually that might be bad since the lower frequency would cause your inductive loads to draw more amps because the alternator may still be trying to regulate the output at 120v and not lowering the voltage proportionately.
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