CTL-713C radar transmitter and treatment of common faults

Abstract The CTL-731C radar transmitter components and working principle of their common failure, and the corresponding approach to the type of radar transmitter in order to ensure the normal work of reference.

Keywords CTL-731C radar transmitter; composition; working principle; failure; treatment

CTL-713C radar is a kind of cloud, rain and other weather target detection and location of the device. Their work is based: the transmitter used to generate high-power RF pulse signal, the antenna and the transceiver switches transmission to the antenna feeder system, radiation from the antenna to the space. To ensure the long-range precipitation radar target detection and measurement with a sufficiently large chance of rain, the transmitter should be low repetition rate, wide pulse width and high peak power operation [1,2]. As CTL- 713C-based weather radar is mainly used for detection of 400km within the scope of heavy rain, precipitation, and other large-scale space weather goals, alert hail, typhoons and other disasters, weather, and can be measured within 200km of rain intensity and spatial distribution of precipitation, and the determination of the development of precipitation height of clouds, so to ensure the normal operation of the equipment in the weather information service has an essential position.

1, the composition and working principle of the transmitter
Transmitter by the trigger pulse generator, pulse modulators, high voltage power supply, magnetron oscillator, control and protection circuits, RF systems, power - DC power supply frequency measurement devices and other components [3]. Trigger pulse generator to send the monitor under the control of the trigger pulse to produce an increase is not less than 200V, the width is greater than 2��s, repeat cycle 5ms positive pulse, into the modulator thyratron grid. trigger pulse generator before, due to non-conducting thyratron The modulator in the human line from the high voltage power supply via charging inductor current charging. When the trigger pulse arrives, thyratron ignition and turn on the artificial line discharge to the load, the modulator pulse transformer in the magnetron cathode by width 2��s, the negative rate of about 26kV high-voltage rectangular pulse, the magnetron high-frequency oscillations generated during this period. The high frequency oscillation pulse by the antenna feeder system to the transceiver and the antenna switch. control and protection circuit. so that all parts of the circuit at the transmitter certain order, timing turn, to ensure the magnetron, thyratron and other important components are always in good working condition; when the transmitter fails, high voltage power supply cut off automatically to prevent damage to machine components.

2 common fault with the treatment of the transmitter
Transmitter failure, will monitor the extension of the panel in a "high-pressure overload" indicator light. If this time extension on the right of the high-pressure press monitoring the reset button, the light is still lit, indicating that the transmitter is faulty, or that emission malfunction caused by the accidental factors, such as the occasional surge pulse, or waveguide magnetron ignition, lightning into the waveguide system, the transmitter is not a hardware failure.

2.1 magnetron transmitter high table and there was no indication ammeter
This occurs first check whether the integrity of high voltage fuses. The fuse has blown or bad contact will result in no pressure and magnetic flow direction; check the automatic discharge device and the modulator is fully disengaged. Check whether there are 5 000V regulator output voltage. If the output voltage is abnormal, in accordance with the high voltage modulator circuit, checking the front-end circuit; check the modem and internal high pressure rectifier silicon stack breakdown or blocking ring is composed of two open-type filter with the capacitors, high voltage silicon stack and R1 constitute anti-cut peak circuit. if the breakdown or open circuit, the replacement of damaged components; if direct pressure to a certain extent, the pressure suddenly to 0, then the DC resonant charging circuit in the charging inductor has been bad and need replacing. transfected Download Center free paper affixed to the high table has instructed http://www.hi138.com 2.2, while the magnetron was no indication ammeter
This fault appears to be divided into 2 kinds of situations to maintenance. First off, if when the pressure maintenance, the high table pointer slowly to zero, it indicates that the transmitter is very slow within the capacitor discharge, discharge circuit is not normal, according the following steps to repair: first measurement of pre-test hole on the modem whether the trigger pulse after the pulse turn-on, if not, then measure the thyratron filament both ends of the AC voltage 6.3V; if so, then the thyratron has been damaged, replace gates flow tube. and then, if measured at the non-trigger pulse, then measuring whether the trigger pulse monitor units delivered, if not check the timer monitoring stations; if so, check the +300 V voltage, the transistor and resistor R V are open. Second, turn off the high pressure, high pressure table pointer quickly to zero, then the trigger pulse and the discharge circuit normal, according to the following steps to check: First, preheat the magnetron filament measured at both ends of the state if the AC voltage 10V , if you check the artificial line is open circuit within the capacitor. Second, if measured at both ends of the filament preheat the magnetron high voltage, then the magnetron oscillator has been bad, replace the magnetron. Again, if the measured magnetron filament voltage for 0 or low, then remove the magnetron tube cap, and then measuring the voltage pulse transformer is a warm, if that is the magnetron is bad, replace the magnetron; if No, check or replace the pulse transformer.

High-voltage and current 2.3, but hypertension is not connected to the normal direction
First check the +27 V supply and its load. +27 V voltage protection circuit in the relay transmitter. Line package voltage and operating voltage of the timer. If +27 V power supply circuit is not normal, it will affect the protection circuit in the relay transmitter work , resulting in high pressure can not remain connected. Second, we must check the cooling system. When the air pressure system failure down to the pressure switch is closed enough to jump, high pressure was cut off. If the overload protection circuit is critical, then the re- adjust the overload protection circuit.

2.4 indicates normal but the magnetron high voltage direct current instability (ignition)
Check the high voltage cables for damage; check thyratron, such as thyratron ignition will cause a bad magnetron oscillation is not normal; check whether the ignition of artificial line capacitance, if you replace the capacitor; check the pulse transformer. Pulse Transformer primary winding is connected with the artificial line, two secondary windings connected to the magnetron filament ends; if the above conditions are normal, then the magnetron is bad, replace the magnetron.

3 References
[1] He Zhonghong, Wei letter high Qiang. L-band radar transmitter Failure Analysis [J]. Meteorological Research and Applications, 2008,29 (3) :95-96, 101.

[2] Huang Xing, Xi Zemin, Wei Zhong mind, and so on. Radar transmitter power control system design [J]. Ship Electronic Engineering, 2008 (1) :21-22.

[3] Yangchuan Feng, Yuan Xiqiang, Huang Xiushao, so .CINRAD / SA radar transmitter and method of fault diagnosis [J]. Meteorology, 2008,34 (2) :115-118.

[4] Liang, Jin and Yuan .CINRAD / CC Radar Transmitter high voltage power supply repair methods and fault examples [J]. Journal of Shaanxi Meteorology, 2005 (3) :33-34, 36.

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