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The first chapter of the working principle of electromagnetic furnace
Working principle of induction cooker
When the electromagnetic furnace in the normal work, the electromagnetic furnace coil on the coil to generate the alternating magnetic field in the pot with the bottom of the change to the bottom of the pot with a ring current, and the use of small resistance and large current short circuit heat effect to produce heat.
The second chapter is the main part of the electromagnetic oven
1. Ceramic plate: imported high heat resistant ceramic plate.
2. High voltage main substrate: constitute the main current loop.
3. Low pressure main substrate: computer control function.
4. LED circuit board: show the working status and transfer operation instructions.
5. Line: the high frequency alternating current into alternating magnetic field (PAN).
6. Fan components: cooling auxiliary components (FAN).
7. IGBT: through the low current signal, control the big current through (IGBT).
8. Bridge rectifier block: the AC power to DC power supply (BD101).
9. Thermal resistance: the heat signal is transmitted to the control circuit.
10. Thermal switch components: induction IGBT operating temperature, so as to protect the IGBT due to overheating damage.
The third chapter is the function of the electromagnetic furnace integrated block
1. C80C49-143A: the central processor integrated fast (Ic1).
2. SN7407N: high voltage output buffer / driver (Ic2).
3. HD74LS145: Four - ten line decoder / driver (Ic4).
4. LM339: low power consumption, low offset voltage comparator (IC6, Ic5).
5. TA8316S: drive (Ic3).
The working principle of the fourth chapter (PD16).
The electromagnetic oven 220V AC by AC IN port access, to prevent overload and short-circuit of the internal circuit through the
fuse F101. VA is parallel to the pressure sensitive circuit, to prevent the external power supply voltage is too high, often to burn itself to protect the safety of the circuit level. C101 for the filter capacitor, capacity of 2UF. After C101 level for high power rectifier bridge block, the former 220V 50Hz alternating current rectifier pulsating direct current, pulsating DC Dentsu a choke ring and C102 smoothing filtering flow, to the junior pan electromagnetic wire coil, pan wire disk and C103 oscillation capacitor composed of LC oscillating circuit for DC will be relatively stable to online disk produced an alternating magnetic field.
After the PAN T102 is a current sampling transformer, the current signal is transmitted to the voltage comparator LM339 through the T102 secondary.
After T102 for high voltage protection diode D, is used to protect IGBT, IGBT to prevent reverse voltage breakdown. The control of the IGBT is driven by the driver TA8316S, the pulse of the TA8316S output 14KHz frequency, according to the width of the TA8316S output to adjust the length of the IGBT pass, so as to achieve the requirements of the power adjustment.
LM339 is a voltage comparator, PD16 uses two blocks of LM339: one for IC5, the main function for the boiler with detection, temperature detection; the other is IC6, the main function for current detection, voltage detection. IC5, IC6 two LM339 comparator will detect signal feedback to the TA8316S drive, so as to achieve the requirements of the power adjustment.
The thermal resistance RT of the wire is converted to the level of the level of the heat change, and then the signal is transferred to the TA8316S by the Q601 transistor, so as to adjust the size of the power to adjust the temperature of the boiler.
IGBT radiating aluminum block is fixed with a temperature switch K1, when IGBT overheat, temperature switch K1 on-off state changes, thereby connecting the IC integrated block 1 foot, through changes in the level of the foot level, so that IC integrated block 4 pin reset down time.
Fan power control by iC4, the 7 foot output high level to triode tube Q703, so that Q703 conduction, fan with 12V DC operation.
The power supply of the control circuit is mainly composed of the primary access of the T101 transformer, and the secondary output is connected with the three groups of series voltage regulators. A group of ZD204, C207, R204, Q203 form +5V voltage, the main supply integrated block IC1 power supply; a set of ZD201, R203, C203, Q201 form +24V voltage, the main supply of integrated IC3 power supply. Another set of ZD203, R203, C205, Q202, R202 form +12V, +10V power supply, +12V power supply, power supply, +10V supply IC6, Q301, ICS,, Q602, Q601, Q501 power supply.
Fifth chapter fault analysis and maintenance method
1. Power on fire insurance.。
① First of all, the wire of the electromagnetic wire is broken into the insurance tube, measuring the voltage across the capacitor C102, the general bridge rectifier DC output voltage of 220V-300V, such as no voltage or continue to burn insurance, determine the bridge rectifier block bad.
Analysis reason: if the bridge breakdown, the 220V alternating current.
② C102 both ends of the voltage, the judge for the IGBT bad, after the failure of the exclusion.
Analysis of the reasons: C102 both ends of the voltage, the bridge rectifier DC output normal, if the IGBT of the two output pin breakdown, is equivalent to the DC short-circuit.
③ Bridge and IGBT are not bad, but still burn insurance, IA8316S integrated block bad, after changing the trouble shooting.
Analysis reason: because the TA8316S output pulse angle is too large, resulting in the phenomenon of overload of IGBT
2. The wind turbine does not work
① Dial the fan plug line, detection of 12V power supply, if there is a bad fan motor.
Analysis of causes: power supply is normal, the fan motor is usually short circuit or open circuit.
② FAN plug line without 12V voltage, drive transistor Q703 emitter breakdown, for Q703, troubleshooting.
Analysis: when the Q703 is not bad, the integrated block IC4 is bad, for the IC4 integrated block, troubleshooting.
③ The fan motor and Q703 are not bad, the integrated circuit block IC4 is bad, the IC4 integrated block, the fault is released.
Analysis of reasons: if the integrated circuit block IC4 seventh pin without high level output, then the launch of the Q703 is not bias voltage, Q703 integrated circuit is still very high, power is in the circuit state.
3. The boot operation is normal, but not heating.
① Measure the TA8316S of the first foot with no 18V voltage, such as no, can check the Q201 has no breakdown, ZD201 has no breakdown, such as the breakdown of the breakdown after the exclusion.
Analysis of reasons: if the TA8316S pin no 18V voltage, the fault point should be in series with the power supply power supply circuit, it must first check the basic components of the series regulator circuit.
② TA8316S the first leg of the 18V voltage, fault should be integrated in the IC3 block TA8316S, after the failure of the exclusion.
Analysis of the reasons: LED display and normal operation, the computer control circuit is basically normal, do not burn insurance, it shows that the high pressure plate is basically normal, but because the TA8316S without pulse output to the IGBT control, IGBT isn't guide.
4. after the boot, the panel lights flashing
① The crystal is bad, change, troubleshooting.
Cause analysis: Crystal bad, cause CPU clock frequency of the input, so that the entire IC1 central processor control.