Generator and Microwave

10-15-2005, 07:18 PM
How come my 1000 watt generator won't run my 750 watt microwave? It surges and the overload lite comes on! Why should it overload?

10-15-2005, 08:34 PM
Your generator is probably SURGE rated for 1000 watts for very short periods of time and is probably maxed at an 800 watts. If the generator is on the low side in voltage output, it will knock down its output also. The microwave's power in theory is 750 watts but in reality probably pulls 800 watts and an extension cord even adds more amps. Simply stated, your generator is not rated to power that microwave since they are real close in power and consumption. Look at the back of the microwave and see what is actually pulls in amps and then multiply by 120 which would give you watts. You might want to put a voltage check on the generator at full load and see how many volts it puts out. Some generators, like the Yamaha I used to own, have a voltage adjustment screw that you can adjust the voltage.

10-16-2005, 06:36 PM
Wigwam , thanks for the info. I did some checking. The microwave doesn't show an amp draw on it. I plugged the microwave directly into the generator and when it was on I checked the generator voltage. It had dropped below 100 volts. It was 122 without the microwave running. The generator is a yamaha 1000 watter. Also the microwave is a 700 watt not a 750. It just seems to me it should run it.

10-17-2005, 03:47 AM
Anytime a generator or the AC line voltage drops below 108 volts, you risk damage to the appliance or tool you are trying to power. LOW voltage DAMAGES AC POWERED equipment. What you can do is add 100 watt light bulbs starting from a single bulb and check the generator's voltage output. See what the generator puts out in terms of voltage when you get to 8 100 watt light bulbs. You might want to check the RPM of the engine to see if it is maxed out at 3600 RPM at full rated load. If it is NOT maxed out in RPMs you can increase the RPMs on the carburator.

Democrat Unlogged
03-03-2006, 06:19 AM
I've been thinking of buying a generator for fishing trips and home power outages, and I may have found the answer to your mystery. I read on several web sites that a microwave rated at "750 watts" actually much more than the capacity of your 1,000-watt generator:

"The power rating used with microwave ovens is the 'cooking power' which refers to the power being 'delivered' to the food being cooked. The actual operating power requirement rating is higher than the cooking power rating (for example, a microwave with 'advertised' rating of 600 watts usually corresponds to almost 1100 watts of power consumption). The actual power consumption is usually stated on the back of the microwave. If the operating power requirement cannot be found on the back of the microwave, check the owner's manual or contact the manufacturer."

"Microwave is rated in watts, relating to the 'cooking watts'. However, microwaves are very inefficient, and it typically takes almost twice the power to deliver the 'cooking watts'. Thus an '800 watt microwave' is likely to require 1600 watts of power to run."

"The power used by a microwave oven is also a bit confusing for the novice to appreciate. When you look at microwave ovens in the shop, most will have a big glossy label advertising the output power. This label will typically read between 500 - 1000 watts. Many people will assume that this is the power that the appliance consumes. This is not the case! The actual power drawn from the power point is typically 40% greater. We recently checked a typical microwave oven. The glossy label advertised the output power to be 800W. The compliance specification label read 1150W. When run off a Selectronic SA22 Sine Wave inverter, the current draw on the DC side was 70A @ 24V or 1680W - more than double the advertised 'output power'."

Democrat Unlogged
03-03-2006, 06:20 AM
Oops, the 2nd sentence should be -- I read on several web sites that a microwave rated at "750 watts" actually draws much more than the capacity of your 1,000-watt generator:

03-03-2006, 07:32 PM
I have a 1000w microwave and it actual needs 1400watts to run. So you are probally boderline with your microwaves are power suckers I would go with at least a 2000w and you eill have no problems. Good luck.

03-03-2006, 07:32 PM
I have a 1000w microwave and it actual needs 1400watts to run. So you are probally boderline with your microwaves are power suckers I would go with at least a 2000w and you eill have no problems. Good luck.

Democrat Unlogged
03-04-2006, 12:34 AM
It's tempting to save a couple hundred bucks (and lug less weight around) by buying a 1000-watter. But I'll probably go with the Honda EU2000, because ...

1. The manufacturer of my on-board charger says a 1000-watt generator with a "good sine wave" (i.e., inverter design) will work but, they recommend at least 1500 watts.

2. Using a small microwave on my fishing/camping trips is much faster than cooking on a camp stove. Meal prep takes 5 minutes instead of 90 minutes, and because I use paper plates in the microwave, there's no dishes to wash afterward. This translates into more time to fish.

3. If I spend several hundred $$$ on a generator, I want to use it for home backup during power outages. A 1000-watt unit won't run a microwave or electric fry pan, and might not run my desktop computer either. The 2000-watt unit can handle these chores (not all at the same time) plus run the blower on my fireplace insert (the furnace doesn't work when the power is out) and a couple lights.

Inverter units are more expensive, but deliver "clean" power you can use to run computers, and are much quieter (this is important in campgrounds, if you don't want to be unpopular).

The top brands, Honda and Yamaha, are equal in quality and price. Another brand, Kipor, makes superficially similar 1000 and 2000 watt inverter generators that sell for a hundred or so less, but I can't vouch for its quality (this brand is popular in Europe, but new to the U.S. market). I would stick with Honda or Yamaha because you know what you're getting. Unfortunately, Yamaha does not make a 2000-watt unit comparable to Honda's or Kipor's, but if you want a 1000-watter the Yamaha is as good or better a choice than the Honda.

Honda wants to support their retail dealers and doesn't like internet discounters undercutting the MSRP. That's why many internet sellers have discontinued Honda's line, and those who carry it don't post prices on their web site.

The best on-line price I've found is Wise Sales, 1-800-916-9473. I found this company by browsing RV chat boards. They gave me quotes over the phone as follows:

Honda EU1000i -- $629.00
Honda EU2000i -- $869.00

I think that's with free shipping but you'd better ask first to make sure. Wise also sells the Honda units, and here again, their prices are the best I've seen to date. They want $655.99 for the Yamaha EF1000iC.

Hayes Equipment (1-800-375-7767) sells the Kipor inverter units for $549 (1000-watt) or $749 (2000-watt), and also sell Kipor non-inverted units ($419 for 1000 watt, $589 for 2000-watt). Hayes advertises free shipping on their web site.

Dem UL
03-04-2006, 12:37 AM
Oops, that should say, "Wise also sells the Yamaha units"

04-27-2011, 03:25 PM
Dose any one know of a Microwave I can by that will work on a 1000w honda generator

Robert M
04-27-2011, 05:46 PM
I had a EU 2000 Honda generator I believe is rated to put out like 1600. It would run a microwave OK but you wouldnt want to run a toaster or coffee pot at the same time. Those draw a lot of power. Lights and TVs dont draw all that much. 100 W light bulb draws 100W so you could run like 16 of them with a 2000 generator.

04-27-2011, 06:03 PM
All of the posts are right on, but for your own information, look on the bottom or the back of the microwave and you will find a label or a stamping on the sheet metal indicating the voltage for the unit, as well as the wattage for the unit.

My guess is that you are going to find that your unit draws between 1200 and 1500 watts, which is the reason that you get a voltage drop with a generator that can only supply 1000 watts.