Introduction to the maintenance method of Crouzet solid state relay

Crouzet high-performance solid state relay has been widely used in computer peripheral interface equipment, constant temperature system, temperature regulation, electric furnace heating control, motor control, numerical control machinery, remote control system, industrial automation equipment; signal light, dimming, scintillator, lighting stage lighting Control system; instrumentation, medical equipment, copiers, automatic washing machines; automatic fire protection, security systems, and switching of power capacitors as power grid power compensation, etc., in addition to chemical, coal, etc. in explosion-proof, moisture-proof, anti-corrosion applications There are a lot of uses.
Crouzet High-Resistance Solid State Relays are contactless electronic switches with isolation function. There are no mechanical contact parts during the switching process. Therefore, Crouzet Highs Solid State Relays have the same functions as electromagnetic relays, and are also compatible with logic circuits. Resistance to mechanical shock, unlimited installation position, good moisture, mildew, anti-corrosion performance, excellent performance in explosion protection and ozone pollution prevention, low input power, high sensitivity, low control power, good electromagnetic compatibility, low noise And high working frequency.
Crouzet High Nos Solid State Relay Advantages
(1) High life, high reliability: Solid state relays have no mechanical parts, and the solid-state devices complete the contact function. Because there are no moving parts, they can work in high shock and vibration environments, due to the components that make up the solid state relay. The inherent characteristics of the solid state relay determine the long life and high reliability.
(2) High sensitivity, low control power and good electromagnetic compatibility: Solid-state relays have a wide input voltage range and low drive power, and are compatible with most logic integrated circuits without adding buffers or drivers.
(3) Fast conversion: Since the solid state relay uses a solid device, the switching speed can be from several milliseconds to several microseconds.
(4) Small electromagnetic interference: The solid state relay has no input "coil", and does not touch the ignition arc and rebound, thus reducing electromagnetic interference. Most AC output solid state relays are zero voltage switches that conduct at zero voltage and turn off at zero current, reducing sudden interruptions in current waveforms, reducing switching transient effects.
Crouzet High Nos Solid State Relay Faults
(1) The tube voltage drop after conduction is large, the forward voltage drop of thyristor or bidirectional silicon control can reach 1~2V, and the saturation voltage drop of high power transistor is also between 1~2V, general power FET The on-resistance is also greater than the contact resistance of the mechanical contacts.
(2) The semiconductor device can still have a leakage current of several microamperes to several milliamps after being turned off, so that ideal electrical isolation cannot be achieved.
(3) Since the tube voltage drop is large, the power consumption and heat generation after conduction are also large, and the volume of the high-power solid-state relay is much larger than that of the electromagnetic relay of the same capacity, and the cost is also high.
(4) The temperature characteristics of electronic components and the anti-interference ability of electronic circuits are poor, and the radiation resistance is also poor. If no effective measures are taken, the operational reliability is low.
(5) Solid state relays have greater sensitivity to overload and must be overload protected with fast fuses or RC damping circuits. The load of the Crouzet High-Solution Solid State Relay is significantly related to the ambient temperature. As the temperature rises, the load capacity will drop rapidly.
(6) The main deficiency is the presence of on-state voltage drop (requires corresponding heat dissipation measures), off-state leakage current, AC/DC cannot be used universally, the number of contact groups is small, and overcurrent, overvoltage and voltage rise rate, current rise rate, etc. The indicator is poor.

Crouzet high-nosed solid state relay maintenance method

1. When using the solid state relay used in the small current specification printed circuit board, the lead terminal is made of high thermal conductivity material, and the welding should be carried out under the condition of temperature less than 250 ° C and time less than 10 S, for example, considering the ambient temperature. If necessary, derating can be considered. Generally, the load current is controlled within 1/2 of the rated value.
2. Selection of solid state relay SSR for various load surge characteristics
The controlled load will generate a large inrush current at the moment of turning on, and the internal thyristor of the SSR may be damaged due to the inability to dissipate heat. Therefore, the user should analyze the surge characteristics of the controlled load when selecting the relay, and then analyze Select the relay. The relay can withstand the surge current under the premise of ensuring steady state operation. Refer to Table 2 for the derating factor of various loads (at normal temperature).
If the selected Crouzet Highs solid state relay is to be operated in a place with frequent operation, long life and high reliability requirements, it should be multiplied by 0.6 on the basis of Table 2 to ensure reliable operation.
Generally, the above principle is followed in the selection. In the low voltage requirement, the signal distortion is small, and the MOSFET can be used as the DC solid-state repeater of the output device; for the AC resistive load and most inductive loads, the zero-crossing relay can be selected. Extends load and relay life and also reduces its own RF interference. For phase output control, a random type solid state relay should be used.
3. Effects of using ambient temperature
The load capacity of Crouzet's solid state relays is greatly affected by the ambient temperature and its own temperature rise. During installation and use, it should be ensured that it has good heat dissipation conditions. Products with rated working current above 10A should be equipped with radiators, 100A. The above products should be equipped with a radiator and a fan for strong cooling. Pay attention to the good contact between the bottom of the relay and the heat sink during installation, and consider applying proper amount of thermal grease to achieve the best heat dissipation. For example, when Crouzet Highos solid state relays work in high temperature for a long time (40 °C ~ 80 °C), users can consider derating to ensure normal operation according to the maximum output current and ambient temperature curve data provided by the manufacturer.
4. Overcurrent and overvoltage protection measures
When using Crouzet's high-nosed solid-state relay, the overcurrent and load short-circuit will cause permanent damage to the SCR solid-state relay's internal output thyristor. Consider adding a fast-blow fuse and air switch to the control loop to protect it. Product output protection, built-in varistor absorption circuit and RC snubber, can absorb surge voltage and improve dv / dt tolerance); also can be connected to the RC absorption circuit and varistor (MOV) at the output of the relay to achieve output protection . The selection principle is that 500V selects 500V-600V varistor for 220V, and 800V-900V varistor for 380V.
5. Relay input loop signal
In use, when the input voltage is too high or the input current is too large to exceed its specified rated parameters, consider connecting the voltage divider resistor at the input terminal or connecting the shunt resistor at the input port so that the input signal does not exceed its rated value. .
6 In the specific use, the control signal and load power supply requirements are stable, the fluctuation should not exceed 10%, otherwise the voltage regulation measures should be taken.
7. Keep away from electromagnetic interference and RF interference sources during installation and use to prevent the relay from malfunctioning.
8. When the solid state relay is open and there is voltage at the load end, there will be a certain leakage current at the output end, so be careful when using or designing.
9. When the Crouzet High-Solid Solid State Relay fails to be replaced, the original model or the same technical parameters should be selected as much as possible to match the original application line to ensure reliable operation of the system.