1, power supply lineQuality: If the home power line aging or overcrowded, then the electrical performance of the power supply line may be limited, resulting in low electric induction cooker.
2, induction cooker wire line aging or the use of unqualified wire line may also lead to induction cooker voltage is too low. At this time, it is necessary to check whether the wire line connected to the induction cooker uses a qualified wire line, and check whether the wire line is aging and damaged, and if the problem is found, replace it in time to solve the problem of too low voltage of the induction cooker.
3, induction cooker voltage is too low reason may be unstable power supply or line aging and other problems.First of all, we can check the power supply line to ensure that the line is normally connected and there is no break or short circuit phenomenon. If the voltage is too low due to line aging, you can consider replacing the line or repairing it.
4, check the power cord: First, check whether the power cord is damaged or loose. If the power line contact is poor, or the wiring is damaged, the induction cooker will appear low voltage. If the power cable is faulty, replace it in time.
5, Check the inductor coil: check whether the inductor coil is damaged or loose. If the inductor is found to be damaged, it needs to be replaced.
6, checkCheck whether the power cable and plug are properly connected. The power cord or plug may be loose or have poor contact, resulting in a low voltage. Reconnect the power cable and plug to ensure that they are secure. Clean the bottom of the induction cooker.
When the grid voltage is normal, U48V of 1/4LM339, U5=8V, the output is open, the overvoltage protection circuit does not work, and the emitter follower BG1 as a positive feedback is a guideYes.
LM339 integrated block adopts C-14 package, appearance and pin arrangement are shown in the figure. Due to the flexible use of LM339, widely used, so the world's major IC manufacturers, companies compete to launch their own four comparators, such as IR233ANI33SF339, their parameters are basically the same, can be used interchangeably.
Induction cooker LM33 voltage offset is small, generally 2mV. The common model circumference is very large, from 0v to the power supply voltage reduction of 5v. The internal resistance limit to the comparison signal source is very wide. The LM339 vcc has a wide voltage range of 2-36 for a single power supplyV, dual power supply voltage is ±1V-±18V; The output potential can be selected flexibly and conveniently.
① When the coil disk is connected in standby mode, use a multimeter to measure the working voltage of pin 8 and pin 9 of U1-LM339 (pin 8 is 75V, pin 9 is 9V). If the voltage is abnormal, check the R1RRR23C21C20D213 and replace the faulty component to rectify the fault.
The three basic voltage measuring points of the induction cooker illustrate the DC300V measurement. The AC 220V is rectified by the rectifier bridge pile, inductance and capacitance filtering, and the output DC voltage of about 310V is added to the electromagnetic wire reel, so the electromagnetic wire reel terminal is the measuring point.
This power supply is designed with two operating voltages, respectively 12V and 5V. The maximum power processing capacity is 10W, and the output voltage is 12V. The peak current of the first output is 900mA.
The voltage of induction cooker is generally 220V and 110V, which depends on different countries and regionsFactors such as power standards and grid voltage.
is 7V, prompting U4 to be greater than U5, which makes the state after flipping extremely stable, avoiding the phenomenon of instability caused by small fluctuations in the power grid voltage near the overvoltage point.
Volts is the most normal and is the rated voltage. In fact, 200 volts to 240 volts are considered within the normal range.
U is the line voltage, single-phase is 220V cosφ is the electrical power factor, the power factor of high-frequency induction cooker can reach up to 0.9 induction furnace circuit line current: I=P/Ucosφ=2000/220*0.9=2000/198=10A By calculation, the induction cooker circuit only needs to be able to carry 15A current wire.
1, can be replaced, under normal circumstances, the CPU can not detect the feedback signal voltage will automatically send an alarm signal, but when the feedback signal voltage is in a critical state between enough and insufficientThe instruction issued by the CPU will be in the test → normal heating → test cycle action, resulting in a fault that the indicator light indicates normal after starting, but does not heat.
2, I can tell you exactly, definitely interchangeable. If I remember correctly, LM339 is a 4-channel comparator with an OC output structure, which means that the pull-up resistor needs to be connected at the output end when used. NS, TI, ST, and ON all have this product, which is also called P/N. AS339 should be the product of BCD.
3, output pulse by LM339 (four voltage comparator)The signal. 1: The trigger part is composed of two groups of positive and negative power supplies, the pipe is composed of PNPNPN, similar to this circuit, the latter stage is mostly composed of multiple high-power tubes, forming a high-voltage switch part, in the replacement, the former can be replaced with a damped pipe.
4, if there is no suitable voltage regulator can be replaced by two regulator tubes in series, so that the voltage regulator value can be added to about 14V. VR1 adjusts the charging opening voltage by adjusting VR1 so that the charging opening voltage is around 11V. Component selection: Q1 is C1815, β≥ 100. Q2 is S8050β≥ 100.
1, the IGBT heat dissipation aluminum block is fixed on the temperature switch K1, when the IGBT is overheated, the on-off state of the temperature switch K1 changes, so that the IC1 integrated block ① foot, through the change of the level of the foot, so that the IC1 integrated block ④ foot reset and stop.
2, the first foot 14V, the second foot 0.26V, the third foot 145V, the fourth foot 12V, the 5th foot 7V, the 6th foot 86V, the 7th foot 02V, the 8th foot 37V, the 9th foot 76V, the 10th foot 64V, the 11th foot 88V, the 12th foot 0V.
3, each pin voltage of the induction cooker is 14V at the first foot, 0.26V at the second foot, 145V at the third foot, 12V at the fourth foot, 7V at the fifth foot, 86V at the sixth foot, 02V at the seventh foot, 37V at the eighth foot, 76V at the ninth foot, 64V at the 10th foot, 88V at the 11th foot and 0V at the 12th foot.
4, pulse cooker circuit: IBGT C extreme high voltageThe pulses are sent to the reverse input pin of an amplifier inside the LM339 after partial voltage of R10, R9, and R41. The same direction input pin from the power supply through R49, R64 voltage, input a fixed voltage. This forms a comparator.
5, the pin voltage is not logical, check whether the component connected to the pin is bad. If not, change it to 339.
6. ④ Check whether the LM339 is damaged. ⑤ Whether C10 is open, if open, the IGBT PWM pulse will not be sent to the IGBT_G pin. ⑥Q131 Check whether the device is powered on or damaged. ⑦ Whether R2R24 is damagedIs furnace LM339 each pin voltage correct?
1, each pin voltage of the induction cooker is 14V at the first foot, 0.26V at the second foot, 145V at the third foot, 12V at the fourth foot, 7V at the fifth foot, 86V at the sixth foot, 02V at the seventh foot, 37V at the eighth foot, 76V at the ninth foot, 64V at the 10th foot, 88V at the 11th foot and 0V at the 12th foot.
2, the first foot 14V, the second foot 0.26V, the third foot 145V, the fourth foot 12V, the fifth foot 7V, the sixth foot 86V, the seventh foot 02V, the eighth foot 37V, the second footFoot 9 76V, foot 10 64V, foot 11 88V, foot 12 0V.
3, is a 4 voltage comparator, in addition to the power supply and the ground pin other pin voltage according to the circuit design, there is no standard value.
4, in the induction cooker inside the LM339 each foot voltage only one foot is unchanged, that is, 12 feet, this foot is grounded, is 0V. Other pins will vary in voltage due to different brands and models of circuits. For example, the third pin is a power supply pin, and the voltage is 17V ~ 21V.
5. Output phase of LM339Applies to a transistor without collector resistance. In use, the output must be connected to a positive resistor (called a pull-up resistor, 3-15K). Choosing pull-up resistors with different values will affect the high potential value at the output.