Dual power switching applications are also very extensive, we simply look at how to use relays, contactors to achieve automatic switching.
Two contactors achieve switching
The coil of the standby power supply is normally closed at the main contactor, and the main power contactor pulls the main circuit to conduct. The main power supply is turned off and the standby power is turned on by the normally closed point of the main contactor. If the main power supply returns to normal, the standby power supply is disconnected.
Of course, you can also use the contactor interlock to achieve, that is a little trouble, and the main power and standby power at the same time how to do? Therefore, the kind of work that you have to work in order does not need to be bothered. The method is not unique.
One relay two contactors
The contactor coils of the mains supply go to the normally open contacts of the relays, and the contactor coils of the standby power supply go to the normally closed contacts of the relays.
When the main line is powered, the relay pulls in, the normally open contact closes, and the main line conducts. Normally closed contact opens, standby power does not work. When the main line is powered off, the relay is also powered off. The normally open contact resumes the initial disconnected state and the main line is disconnected. The contactor of the backup circuit starts working through the normally closed contact of the relay.
Double conversion contact relay
This is similar to the above, except that this relay is a double changeover contact. When the power is on, the two contacts are closed. Both contacts close when the power is off. An electrical component can be completed. If the A-way is a single-phase 220 volt power supply, the coil voltage of the relay is also 220 volts AC.
Contactors and relays have time lags when they are switched on and off, and they have a short-term reaction to equipment or appliances that require high power. For example, the light bulb flickered and the motor paused. If it is a self-locking line, you will find that the electrical equipment is not working.
Dual power switch
This cost is a bit high and needs to be manual. If you have a good friend, you can build a control circuit yourself.
There must be a short time difference in power conversion, and it is impossible to achieve seamless connection in the middle.
It is mainly used in uninterruptible power supply places. It can automatically switch the load-consuming equipment to another standby power supply after the failure of the normal power supply line to maintain the normal operation of the equipment.
Classification of dual power switch
(1), STS static switch
It is also called static transfer switch. It is an automatic switching system for power supply selection. After the first channel fails, STS automatically switches to the second channel to supply power to the load (premise that the second channel is normal and basically synchronized with the first channel). If the road fails, the STS automatically switches to the first road to supply power to the load (if the first road is normal and the second road is basically synchronized).
Suitable for UPS-UPS, UPS-generators, UPS-city power, city power-city power, and any two-way power conversion. All above power supplies need synchronizing devices to ensure that the two power supplies are basically synchronized, otherwise STS cannot Switch.
It is mainly composed of intelligent control board, high-speed thyristor and circuit breaker. Its standard switching time is ≤8ms, which will not cause IT class load to be powered off. It not only provides reliable power supply to the load, but also ensures the safety of the STS in different phases.
(2), ATS automatic transfer switch
ATS is mainly used in emergency power supply systems to automatically switch load circuits from one power source to another (standby) power switchgear to ensure that critical loads are continuously and reliably operated. ATS is a mechanical structure, and the conversion time is more than 100 milliseconds, which will cause the load to lose power. Suitable for lighting, motor load.
Dual power switcher distinguish between PC grade and CB grade
The dual power switch is divided into PC level and CB level. The two structures are roughly the same. The PC grade is isolated, like a double-throw knife switch, plus an operating mechanism. The CB class is a circuit breaker protection type. It consists of two circuit breakers plus an operating mechanism. It has an overload short circuit protection and is the same as the circuit breaker protection. The user should consider from the following aspects when choosing.
(1) Consider from the reliability point of view. PC-level reliability is higher than CB-level, PC-level uses mechanical + electronic conversion action locks, and CB-level uses electronic conversion-action locks. Therefore, in some workplaces with relatively high safety requirements, it is recommended to select PC-level products.
(2) Consider from the perspective of switching time. The switching time of the two products is not the same. PC grade products are commonly used on geared motors. Because the motor rotates at a high speed (16-22 r/min), after the circuit fails, the motor speed must be decelerated to a certain degree to trigger the switching mechanism to break. Open, the action time is relatively slow, although the switching time is slow, but as a mechanical product is still more to consider from the perspective of durability. Class CB products are commonly used in residential buildings, where faulty power supply is easily disconnected and switching time is fast.
(3) There is no short-circuit protection function for the PC-class dual-power-supply switch. Whether or not the user adds additional circuit-breakers should be considered according to whether or not the circuit system is needed. Dual-power switching switch Its role is to achieve dual-channel power conversion, whether the short-circuit protection function will not affect its operation. Many people think that the short-circuit function is used to protect the switch. This is a misunderstanding.
(4) Installation of isolating switches will occupy space, increase costs, and reduce reliability. It is recommended that the number of disconnectors in industrial power systems be controlled. There is no need to install disconnectors in residential buildings.
Guangzhou Mingye Electronic Technology Co., Ltd. manufactures and sells tension controllers, phase sequence protectors, rs485 acquisitions, control modules, plc driver boards, relay modules, circuit board rapid custom development, new fan control, automatic testing, and intelligent testing. 17 years of advanced manufacturing experience, domestic well-known magnetic powder tension controller manufacturers, all over the country, factory direct sales, consulting and ordering telephone, Mr. Huang. If there are more questions or demands, please contact Guangzhou Mingye Electronics official website for free consultation.
Kindwin Technology (H.K.) Limited , https://www.ktlleds.com