Related Manuals for Panasonic Microwave Ovens with Inverters
Summary of Contents for Panasonic Microwave Ovens with Inverters
- Page 1 Technical Guide Microwave Ovens with Inverters Panasonic Services Company National Training...
- Page 2 Prepared by: César Perdomo Panasonic Services Company National Training Department Secaucus, NJ Warning This service information is designed for experienced repair technicians only and is not designed for use by the general public. It does not contain warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product.
- Page 3 Objective The objective of this course is to provide the student with information about the latest technology used in Panasonic’s new line of microwave ovens. Upon successful completion of this course, the student will learn the differences between the high voltage circuit used in most microwave ovens, and the Inverter technology used in this line of Panasonic microwave ovens.
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Page 5: Table Of Contents
Table Of Contents Microwave ......................1 What are Microwaves?..................1 How do microwaves cook?................1 Inverter Technology....................2 Difference Between MWO without Inverter and MWO with Inverter ....2 Major components....................4 Magnetron ......................4 How to diagnose for an open filament or a shorted magnetron ......4 Oven cavity .......................5 Turntable ......................5 Primary/secondary latch switches ..............6... -
Page 6: Microwave
Microwave What are Microwaves? Microwaves, like visible light, are a part of the electromagnetic radiation spectrum. They are extremely high frequency radio waves. As the frequency of radiation increases, its wavelength decreases. The very high frequencies correspond to very short wavelengths; hence the name microwaves. Infrared radiation, ultraviolet light and X-rays are also electromagnetic radiations, but have even shorter wavelengths than microwaves. -
Page 7: Inverter Technology
Inverter Technology Panasonic uses proprietary Inverter technology in most of its microwave ovens. Difference Between Traditional and Inverter Microwave Ovens Traditional microwave ovens Conventional microwaves ovens use power transformers to increase the household line voltage (120 VAC at 60 Hz) to a level high enough to operate the magnetron. - Page 8 Power Level Comparison Figure 1 Traditional microwaves send out a single level of power in small bursts to cook food at different speeds. For example, when set at 60% power, the microwave energy would be on 60% of the time and idle 40% of the time. Inverter microwaves, however, give accurate, true multiple power levels.
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Page 9: Major Components
Major components. Magnetron In a microwave oven, the magnetron is used to produce the high frequency required for cooking. The frequency of microwaves for general cooking is 2,450MHz. Magnetron components Cooling Fins Antenna Filament Terminals Antenna Gasket Figure 3 How to diagnose for an open filament or a shorted magnetron To check for open filament: •... -
Page 10: Oven Cavity
Whenever you replace the magnetron, measure for radiation leakage before the outer panel is installed and after all necessary components are replaced or adjusted. Warning: Special care should be taken in measuring around the magnetron. Avoid contact with any of the high voltage parts while conducting the radiation leakage test. -
Page 11: Primary/Secondary Latch Switches
Primary / secondary latch switches These are safety switches, and their basic function is to interrupt the power supply to the magnetron when the door starts to open. They are open when the door is opened. Switch position Switch Door Opened Door Closed Primary Open... - Page 12 Adjustment of the primary latch switch, the secondary latch switch, and the short switch 1. Mount the primary latch switch, the secondary latch switch, and the short switch to the door hook assembly as shown in the figure 7. NOTE: No specific individual adjustments during installation of the primary latch switch, secondary latch switch or short switch to the door hook are required.
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Page 13: Temperature Sensors
Temperature Sensors This microwave oven uses 2 different types of temperature sensors. One is a thermal cutout sensor located on top of the oven cavity, and the other is a thermistor, which is mounted on the side of the magnetron. See Figure 8. The thermal cutout sensor is used to stop the flow of AC to the oven, if the cavity surface overheats for any reason. -
Page 14: Steam Sensor
Steam Sensor This sensor detects the presence of steam emitted by the food being heated and then, based on how long it took to reach the steam stage, it gauges how much longer it should cook, before shutting off. The steam sensor works just like the effect called piezoelectricity. The piezoelectricity effect generates electricity when mechanical shock is applied to the general dielectrics material. -
Page 15: How To Check The Steam-Sensor Function
Side view of the microwave oven illustrating the steam operation Hot Steam Steam Sensor Door Turntable Figure 11 How to check the steam-sensor function. To determine if this function is working ok, do the following: 1. Place a water load of 150 cc in the oven. 2. -
Page 16: Inverter Circuit
Inverter Circuit For information about the inverter power supply turn to pages 2 and 3.…. Inverter Power supply Heat sink High Voltage Transformer CN702 AC Input CN703 High Voltage CN701 output to the Control magnetron Signals line Figure 12... - Page 17 Inverter Power Supply Circuit Explanation The inverter power supply circuit uses the AC line 120V, 60Hz to supply 4,000V DC to the magnetron tube. The AC input voltage is rectified by the bridge rectifier DB701 DC voltage is applied to the Switching IGBT (Insulated Gate Bipolar Transistor) circuit.
- Page 18 Inverter Power Supply Circuit IGBT D701 Circui DB701 CT701 D702 Figure 13 Warning 1. Always unplug the microwave oven from the electricity supply, before removing the outer panel. 2. Never touch the inverter PCB with the microwave oven plugged into the electricity supply.
- Page 19 Inverter Power Supply Figure 14...
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Page 20: Test And Measuring Procedures
Test and Measuring Procedures Procedure to check the Inverter using an Ammeter Equipment needed: 1-liter beaker An AC Ammeter. 1. Place the beaker with one liter of water into the oven cavity. 2. Unplug the 2 pins high voltage connector from the plug CN703 on the Inverter power supply. -
Page 21: Measurement Of Microwave Output
Measurement of microwave output The output power of the magnetron can be determined by performing IEC (International Electro-technical Commission) standard test procedures. However, due to the complexity of IEC test procedures, it is recommended to test the magnetron using the simple method outlined below. Equipment necessary: •... -
Page 22: Procedure For Measuring Microwave Energy Leakage
Procedure for measuring microwave energy leakage A radiation leakage test should be done every time the unit is repaired. If the result of the test registers a reading higher than 2mW/cm , contact one of these companies, PASC, PSC, or PCI immediately. The U.S. - Page 23 5. Press the start pad or set the timer and with the magnetron oscillating, measure the leakage by holding the probe perpendicular to the surface being measured. Move it along the edges of the door, the display panel, and the cover at a very slow speed no faster than 1 inch/sec (2.5cm/sec).
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Page 24: Safety Tips
Safety Tips Safety tips for operation of microwave ovens • Do not operate the oven when it is empty. • Exercise extreme caution if you have a pacemaker implant. Microwave radiation may cause pacemaker interference. • Persons with pacemaker implants should not be near a microwave oven unless they are sure that it is in good operating condition and there is no leakage of microwave radiation. -
Page 25: Models Line-Up
Models line-up Mid and Family-Size NNS504W/M NNS614W NNH664B/W NNH764B/W NNT694S NNP794B/W NNP794S Full-Size NNH964B/W NNP994B/W NNP994S NNS254W NNH264B/W/Q NNP294B/W NNP294S Convection NNC980W/B NNC994S... -
Page 26: Features
Lightweight Design ® Panasonic's Inverter Microwave Ovens are lighter, sleeker and more compact than ever before, yet also offer more space inside to prepare food. Panasonic ® Inverter technology replaces bulky capacitors with a compact circuit, reducing the weight and size of our microwave's power supply and providing more room in ®... - Page 27 Button Panel The new “Genius Prestige” ovens use an effortless-to-operate button panel. This panel makes it easier to select the desired settings. The Convection Oven has dials to control the oven’s temperature, time and weight. Menu Action Screen The Menu Action Screen display actually tells you what to do next. The words scroll across the screen, displaying the program you’ve selected and telling you the next step.
- Page 28 Inverter Turbo Defrost The Turbo Defrost feature allows you to defrost foods in almost half the time than previous Panasonic Auto Defrost. Panasonic Inverter Turbo Defrost technology is an advanced microwave sequencing system using the Inverter low- power delivery feature. It was developed on the basis of what scientists call "Chaos...
- Page 29 FutureWave Turntable System Even microwave distribution means even cooking. Panasonic’s FutureWave Turntable System makes it easy. The microwaves come from the side of the oven to ensure that the microwave field evenly covers the top, sides, and bottom of the food.
- Page 30 Microwave Oven Built-in Trim Kit For kitchens with limited space. Panasonic provides optional built-in trim kits which allow you to neatly and securely position a Panasonic microwave oven into an open area of your kitchen. Each kit includes all the necessary assembly pieces and hardware to give your Panasonic microwave oven a custom finish look.
- Page 31 Use the table below to match the model numbers to their respective trim kit model number as well as the dimensions and required cabinet opening. Microwave Oven Built-in Trim Kit For kitchens Outside Trim Kit Model Cabinet Opening Model Number Dimensions of Number (W x H x D)
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Page 32: Functions
1200W microwaves. Auto Cook Menu (15 Categories) You'll have access to detailed menus that help make cooking with this Panasonic over-the-range microwave a simple task, even for the most novice chefs. - Page 33 Easy to Clean Outer Design With no seams or breaks in the outer casing of the microwave oven, and no uneven edges and crevices on the underside of the cabinet, it's a cinch to wipe clean. Delay Start/Timer This feature allows you to program a set amount of time to let food stand after cooking.
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Page 34: Understanding Ionizing & Non-Ionizing Radiation
Understanding Ionizing & Non-Ionizing Radiation There is a distinction made between IONIZING radiation, which has enough energy to physically break chemical bonds at the molecular level, and NON- IONIZING radiation, which does not. Radiation falls within a wide range of energies form the electromagnetic spectrum. - Page 35 Non-ionizing Radiation We take advantage of the properties of non-ionizing radiation for common tasks: • microwave radiation: telecommunications and heating food • infrared radiation: infrared lamps to keep food warm in restaurants • radio waves: broadcasting Non-ionizing radiation ranges from extremely low frequency radiation, shown on the far left through the audible, microwave, and visible portions of the spectrum into the ultraviolet range.
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Page 36: Troubleshooting
Troubleshooting Troubleshooting table Symptom Cause Corrections Oven is dead. 1. Open or loose wire harness Check the fan motor Fuse is ok. 2. Open Thermal cutout. when the cutout is No display and no operation 3. Open low voltage transformer. defective. - Page 37 Symptom Cause Corrections The oven can be 1. Open or loose wiring of secondary switch. Adjust door and latch programmed, but the timer 2. Secondary switch alignment is off. switches does not start to countdown. 3. Defective secondary switch 1. Decrease in AC power source voltage. Check the outlet The microwave output is low.
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Page 38: Inverter Circuit And Magnetron Troubleshooting
Inverter Circuit and Magnetron Troubleshooting This microwave oven is programmed with a self-diagnostic failure code system used for troubleshooting. The error codes H97, H98, and H99 are used to indicate problems related to the inverter circuit and the magnetron. These codes appear on the display window after the start key is pressed and there is no microwave oscillation. -
Page 39: Glossary Of Electronic & Microwave Oven Related Terms
Glossary of Electronic & Microwave Oven Related Terms AC VOLTAGE: An electric current that reverses its direction regularly and continually, thus it is Alternating Current. AMPERAGE: The strength of an electric current measured in amperes. One ampere is the amount of current that flows through one ohm of resistance with one volt applied. - Page 40 CONVECTION: The transmission of heat by the mass movement of the heated air. CORE: A magnetic material that affords an easy path for magnetic lines of flux. CUMULATIVE EFFECT: Many exposures to small doses add up to a large dose. CURRENT LIMITER: A protective device, used in some two-fold applications as a fuse that is designed to limit current flow in high-amperage circuits.
- Page 41 ELECTRON: A high-speed, negatively-charged particle that revolves around the nucleus, and forms a part, of all atoms. ELECTROSTATIC: Pertaining to electricity at rest or to stationary electricity (static electricity), such as a static charge on an object. FERRITE: A ferric oxide material that has both magnetic properties and a high resistance to current flow.
- Page 42 IC: Integrated Circuit. An interconnected network of electrochemical elements integrated into a tiny electronic circuit that performs at least one, and usually more, logic functions. IEC: International Electro-technical Commission. IMPEDANCE: A combination of resistance and reactance that offers opposition to the flow of current in a circuit. Impedance is usually expressed in ohms. INDUCTANCE: The property of a circuit that causes a magnetic field to be produced which tends to oppose any change in the existing current flow.
- Page 43 LED: Light-Emitting Diode. A semi-conductor diode that efficiently converts electric signals into light, and thus glows when current passes through it. In microwave ovens, LEDs are generally used for control panel displays and indicators. LOAD: An object or device that consumes electrical energy, and thus changes the energy into another form.
- Page 44 OPEN CIRCUIT: A circuit that does not provide a complete path for the flow of current. OPTO-COUPLER: See photo-coupler. PARALLEL CIRCUIT: Two or more electrical devices connected to the same pair of terminals so more than one current path is available. Current flows through each device in the parallel circuit.
- Page 45 RESONANT CIRCUIT: (explained in detail in part 3) A coil and capacitor connected in parallel form a capacitive-inductive resonant circuit. Energy supplied to the circuit will charge up the capacitor. When the energy supply is removed, the capacitor discharges through the coil. Current flow through the coil causes a magnetic field to develop around coil.
- Page 46 VOICE SYNTHESIZER: An instrument that simulates speech by digital control. The synthesizer assembles and digitizes the various elements of a dialect, so the appropriate inflections and other speech characteristics of any language can be simulated. VOLT: The unit of electrical potential (electromotive force or electrical pressure). One volt is the pressure required to send one ampere of current through one ohm of resistance.