How To Test Microwave Ovens
Microwave ovens are like any other electrical appliance, in that it will gradually wear out. This is due principally to gradual degradation of the magnetron tube that generates the energy that heats the materials that you put into it. If you’re interested in how a magnetron tube converts high-voltage electricity into microwaves, there’s a Wikipedia entry here. For most of us, though, it’s enough to know that over time, the tube will wear down and produce less microwave energy, requiring more time to bring things to the desired heat. In higher power-rated microwaves, the degradation may be less noticeable for a time, but for lower powered units, a fall-off may mean that the device is no longer very useful.
If you’ve thought that your microwave no longer cooks as quickly or as thoroughly as it used to, you may be correct. One common sign is that you hit a preset power and time setting, such as to pop microwave popcorn or heat a coffee mug of water, and it doesn’t quite do the job. Of course, the speed at which it cooks when it is new depends on the power rating. Higher powered microwaves are often rated at around 1200 Watts, and some even higher. Low power models are typically 700 Watts rated. Anything under 700 Watts is probably not very good for cooking food. You can see how to convert power ratings and times required here.
Down and Dirty Test #1
So, how can you test? Well, the most obvious way is to find out what your microwave’s power rating is (often noted on the back of the appliance, and certainly in the owner’s manual), and use the time for specified power instructions on some microwave friendly food’s preparation instructions. If you don’t want to waste food, a packet of microwave popcorn might be a good place to start. Presumably, if your microwave isn’t heating to what the power rating and time of preparation expectations are, it isn’t performing to specifications, although this assumes that the preparation instructions are accurate.
Down and Dirty Test #2
Another down-and-dirty way of testing is to fill a coffee mug with water and boil it on high (the microwave’s default setting) for 1 minute. The water should in most cases have begun to boil by then. Again, though, this is just presumptive proof that it’s not operating to specification. What it means, more than anything, is that our expectations have been raised to the point where we think that is a reasonable time in which water ought to boil in a microwave.
More Scientific Test: The JIS Microwave Power Method
You can find this method outlined at Celtek Electronics. You need:℃
2 identical 500 mL beakers (or other microwavable containers)
An accurate thermometer
A stirrer (wooden is good, like a popsicle stick/tongue depressor/coffee stirrer)
1) Stir and divide 1000 mL of water that’s 20℃ plus or minus 5℃ into the two containers, to ensure that they are both of the same temperature.
2) Measure the temperatures of both, add those temperatures and divide by two to average the results.
3) Position both containers near the center of the microwave’s turntable. At full power, switch the microwave on for 60 seconds.
4) Remove both containers immediately, stir, and measure the temperatures the same way: note each and add together, then divide by two to average.
5) Now subtract the starting temperature average from the ending temperature average (for example, 40 minus 20 equals 20). Now take that number, and multiply by 70 to give the estimated wattage. In this case, 20 times 70 equals approximately 1400 Watts.
Compare that to the manufacturer’s specified power. If it’s not near the mark, it may be time to get a new microwave oven. Even if it’s close, it may be that your life circumstances have changed, and you find you need a larger capacity or a higher power rating for a growing family, or maybe you’re doing more food preparation than you used to, or you just want a change.
Whatever is causing your dissatisfaction with your microwave, Dave’s Appliance has the experience and the selection to get you the unit that will suit you best. They are happy to put their experience at your service. Give them a call.