Panasonic NN-T695 Service Manual

Also see for INVERTER NN-H665: Operating instructions Instrucciones de operación Operating instructions Operating instructions User manual

Contents

2.1. Variable power cookingcontrolHigh Voltage Inverter Power Supply (U) controls output powerby the signal from Digital Programmer Circuit (DPC). Powerrelay stays ON for P3 to P10 and For P1 to P2, both inverterdrive signal and power relay to control output power.NOTE:The ON/OFF time ratio does not correspond with thepercentage of microwave power since approximately 2seconds are required for heating of magnetronfilament.Variable Power CookingPOWER SETTING OUTPUTPOWER(%)APPROX.ON-OFF TIME OFPOWER RELAY (RY1)ON(SEC) OFF(SEC)HIGH P10 100% 22 0P9 90% 22 0P8 80% 22 0MEDIUM-HIGH P7 70% 22 0MEDIUM P6 60% 22 0P5 50% 22 0P4 40% 22 0MEDIUM-LOW P3 30% 22 0P2 20% 15 7P1 10% 8 14DEFROST P3 30% 22 02.2. Inverter power supply circuitNEW H.V.The Inverter Power Supply circuit powered from the linevoltage, 120V 60Hz AC input supplies 4,000V DC to themagnetron tube, and functions in place ofthe H.V. transformer,the H.V. capacitor and H.V. diode.1. The AC input voltage 120V 60Hz is rectified to DC voltageimmediately.2. DC voltage will be supplied to the switching devices calledIGBT. These devices are switched ON-OFF by the 20 to 40kHz PWM (pulse width modulation) signal from themicrocomputer in the DPC.3. This drives the High voltage transformer to increase voltageup to 2,000V AC.4. Then the half-wave doubler voltage rectifier circuit,consisting of the H.V. diodes and capacitors, generates thenecessary 4,000V DC needed for the magnetron.5. Output power of the magnetron tube is always monitored bythe signal output from the current transformer built into theinverter circuit.6. This signal is fed back to the microcomputer in the DPC todetermine operating conditions and output necessary tocontrol PWM signal to the Inverter Power Supply for controlof the output power.2.3. Inverter defrostWhen the Auto Control feature is selected and the Start pad istapped:1. The digital programer circuit determines the power level andcooking time to complete cooking and indicates theoperating state in the display window. Table shows thecorresponding cooking times for respective serving bycategories.Inverter Turbo DefrostSELECTED WEIGHT COOKING TIME1.0 LB 5 min.00 sec.2. When cooking time in the display window has elapsed, theoven turns off automatically by a control signal from thedigital programmer circuit.2.4. Sensor cooking (Only forsensor models)Auto sensor cooking without setting a power level or selectinga time. All that is necessary is to select an Auto SensorProgram before starting to cook.Understanding Auto Sensor CookingAs the food cooks, a certain amount of steam is produced.If the food is covered, this steam builds up and eventuallyescapes from the container. In Auto Sensor Cooking, acarefully designed instrument, called the steam sensorelement, senses this escape of steam. Then, based uponthe Auto Sensor Program selected, the unit willautomatically determine the correct power level and theproper length of time it will take to cook the food.NOTE:Auto Sensor Cooking is successful with the foods andrecipes found in the Auto Sensor Cooking Guide.Because of the vast differences in food composition,items not mentioned in the Cooking Guide should beprepared in the microwave oven using power selectand time features. Please consult Variable PowerMicrowave Cookbook for procedures.2 DESCRIPTION OF OPERATING SEQUENCE8NN-T695 NN-T685SF