Automatic transfer switch in China has gone through four stages of development, are contactor type, circuit breaker type, load switch type and double throw type.
Contact type: This is the generation of China’s conversion switch. It consists of two AC contactors and mechanical and electrical interlocking device combination, this device because the mechanical interlocking is not reliable, high power consumption and other shortcomings. It’s slowly being eliminated.
Circuit breaker type: this is the second generation, which is usually we often say CB level double power supply. It is a combination of two circuit breakers and mechanical and electrical interlocking devices, with short circuit and overcurrent protection, but is still not reliable in mechanical interlocking.
Load switch type: this is the third generation, it is composed of two load switches and a set of built-in interlocking mechanism combination, its mechanical interlocking is more reliable, the conversion by the electromagnetic coil attraction, so as to drive the switch action, fast.
Double – throw switch: this is what we call the PC pole double – power automatic switch. It is the fourth generation, it is driven by the electromagnetic force, the built-in mechanical connection to maintain the state, the single pole and double throw integration of the transfer switch, has the advantages of simple structure, as well as small, its own chain, fast conversion speed and so on.
The development trend of dual-power automatic transfer switch mainly includes two aspects:
One is the switch body. It needs to be highly resistant to shock current and can be converted frequently. A reliable mechanical interlock, which ensures that no two power sources run side by side under any conditions, also does not allow the use of fuses or tripping devices in case the two power transfer switches are overloaded and the output ends fail.
Another is the controller, the controller is the use of microprocessor and integrated chip intelligent product detection module needs to have a very high detection accuracy, logic judgment module has a wide range of parameter setting and the necessary state display equipment, to meet the requirements of different loads, with good electromagnetic compatibility, Can withstand voltage fluctuations, wave voltage, harmonic interference, electromagnetic interference, but also requires the conversion time to be fast, and the delay can be adjusted, to provide users with a variety of signals and fire linkage interface, communication interface.