How To Check the Output Power (wattage) of a Microwave Oven

 

The following test will provide a suitably accurate measurement of the output power of any microwave oven. Variations or errors in performing this test will produce uncertain results. If the line voltage (from the electrical outlet) is low, the magnetron output will be correspondingly low.

    Procedure:
  1. Pour exactly 1000 mL (1 Liter) of cool tap water into he container. Using the thermometer, stir the water, then measure and record the temperature. For accurate results the water should be about 60 degrees F (20 degrees C).
  2. Place the container on the center of the oven cooking shelf (do not leave the thermometer in the container and remove any metal racks), and heat the water (at full power) for 63 seconds. Use the second hand of a watch, not the oven timer.
  3. After the heating time is completed, immediately remove the container, stir the water, re-measure and record the temperature of the heated water.
  4. Subtract the starting water temperature (step 2) from the ending water temperature (step 3) to obtain the temperature rise.
  5. To determine the output power in watts, multiply the total temperature rise by a factor of:
    38.75 , if you're using a Fahrenheit thermometer;
    70 , if you're using a centigrade thermometer.

Dual Magnetron Systems

Most of the higher-powered commercial models use two 700-watt magnetron tubes, each with their respective high-voltage systems, which produces an output of 1400 watts. Amana's new RC22, DQ22 and MC22 models use three magnetrons to produce a 2200 watt output.

In order to evaluate the independent operation of each individual magnetron, the systems must first be isolated. This is accomplished by disabling one side, then performing an output power test on the functioning side. Either side may be disabled first.

WARNING:

Before touching components or wiring:Make sure the oven is unplugged.
DISCHARGE ALL HIGH VOLTAGE CAPACITORS. Procedure

There is high voltage present, with high-current capabilities, in the circuits of the high voltage section. It is extremely dangerous to work on or near these circuits with the oven energized. DO NOT TOUCH components or wiring while the oven is operating. Use very great caution at all times.

The procedure is as follows. Observing the above safety precautions, first disable one side by carefully disconnecting one or both of the leads from the primary side of the high voltage transformer. (See the illustration to the right). Set the oven to cook at full power and do an output wattage check as outlined above. Having established the functional status of the one side, unplug the oven, discharge the high-voltage capacitors, re-connect the transformer primary wires, and repeat the procedure for the other side.