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 Posted: Tue 23:14, 21 Dec 2010 Post subject: air jordans High-power ultrasonic cleaning machine |
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High-power ultrasonic cleaning machine generator
Tracking transducer within the resonant frequency, so that generators work in the best state: the second to provide overload protection. Figure l Schematic of ultrasonic sound signal generator signal generator 2, mainly by AC / DC conversion circuit and pulse width modulation circuit. PWM control circuit uses analog integrated circuits TIA94 to achieve. TIA94 is a fixed frequency pulse width modulation circuit, built-in linear sawtooth oscillator,[link widoczny dla zalogowanych], the oscillation frequency by an external resistor and a capacitor to adjust the oscillation frequency is: sc = 1. 1/RTC, r. Output pulse width is positive through the ramp on the capacitor Cr voltage and the other two control signals are compared to achieve. Q1 and Q2 control the power output is controlled by NOR gate. When the bistable flip-flop when the clock signal is low only be gated, that is only during the sawtooth voltage is greater than the control signal can be gated. When the control signal increases, the output pulse width will be reduced. 1rI94 electrical circuit,[link widoczny dla zalogowanych], and pulse modulation circuits in Figure 2, Figure 3 shows l21. Circuit Diagram Figure 2TL494 4l George et al: High-power ultrasonic cleaning machine generator ClR pulse modulation circuit in Figure 3,[link widoczny dla zalogowanych], the circuit uses only the error amplifier TLA94 I, base current, so that IGBT turn-on. Instead,[link widoczny dla zalogowanych], the reverse gate voltage increases so will eliminate the error amplifier I1 of rN + (16 feet) Ground, IN one (except channel 15, flows through the reverse base current, the IGBT off. Amp electric foot) received high . To protect the output transistor TLA94, by the way shown in Figure 4. R3 and R4 partial pressure, at 4 feet plus close O3V intermittent adjust the voltage. R1, R2 and C1 form the phase correction and gain control network. Unitary had 4 hours of work impedance match, when the feedback signal is greater than the set value, through the TL494 PWM function, its 9 feet, 1O feet of the output signal pulse width decreases, the drive circuit to drive plastic surgery to enlarge IGBT power devices so that conduction duty cycle decreases, current decreases, to form over-current protection, and then further reduced by the sensor so that the feedback signal to form a single-loop closed-loop control; when the feedback signal is less than the set value, the contrast control process . 3 power amplifiers}, {L-. i - �� A] - �� '- a drive transmission jr - _ �� --- r-__J out --,-. L] variable l, j, 3; pressure fI {device \ 1GBT schematic diagram 4IGBT As a result of the work of the transistor analog amplifier OTL, OCL is only 78% efficiency of circuit theory, the actual efficiency will be lower power consumption. Also, because a single power tube output power is limited, the larger the output power to require more power to control, so the relatively large size; and isolated coral bipolar IGBT, power consumption in the switching moment, but time is short , when the cut-off or turn on the power consumption is very small, a longer time, so the total power consumption, the maximum efficiency of 90%. Therefore, we use IGBT as a power switching device. IGBT switching function is formed by adding a positive gate voltage channel, to the PNP transistors provide a simple matching circuit though (usually there is only one matching inductor), does have an important role. In addition to ultrasonic cleaning machine to solve the matching problem of variable resistance (ie,[link widoczny dla zalogowanych], transform the load resistance, so the best load with the generator are equal), but also solve the tuning problem, that is offset by matching inductor inductance transducer so that the transducer capacitance was purely resistive. In the practical application of capacitive transducers were tested, although not consume power, but will take some divided voltage, resulting in reduced output. The solution is to give the transducer a series matching inductor, the load on the performance of the operating frequency of a pure resistance, when generator output voltage Uo (fundamental of the RMS) all added, the resulting electric power is already dead ��3�� households. If P does not meet the actual requirements (or generator, severe fever, etc.) you need to use transformers for variable resistance in order to get the right transducer power to generator stability. 5 Conclusion After testing, the ultrasonic generator standard sine wave output, operating frequency 22-28kHz adjustable output current of 7A or so, power up to 1800W or so. Continuous work in the long stable and reliable power, a substantial increase in cleaning effect, the technical indicators have reached the desired design goals. References: l�� ��Wangen Qing, Ren Guan-bao. The technology of ultrasonic cleaning machine status and recommendations [J] Cleaning Technology, 2oo4 (6): 29. ��2�� Xu Tao. On the ultrasonic generator power technology lJ]. Cleaning Technology. 2004 (6): 10.15. ��3�� Baoshan Qing, Wang Yandong. Ultrasonic cleaning machine impedance matching circuit ��J], clean technology. 2004 (5): 12.
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