One minute to understand the application of dual power automatic switching devices in low-voltage switchgear
ZHONGFEIYA TECH, as a manufacturer specializing in the production of high and low voltage switch cabinets, often uses dual power switching devices when producing low voltage switch cabinets. So let’s briefly introduce the application of dual power switching devices. Let’s take a brief look at how to use relays. The contactor realizes automatic switching. The application of dual power switching is very wide. Let's take a brief look at how to use relays and contactors to realize automatic switching.
The coil of the standby power supply goes to the normally closed point of the main contactor, and the main power contactor pulls in the main circuit to conduct. The main power supply is cut off, and the backup power supply is conducted through the normally closed point of the main contactor. If the main power supply returns to normal, the backup power supply is disconnected.
Of course, it can also be realized by contactor interlocking, which is a bit more troublesome, and what should be done when the main power supply and the backup power supply have power at the same time? Therefore, it is necessary to connect to the kind of sequential work, it does not have to be so troublesome, and the method is not unique.
The contactor coil of the main power supply uses the normally open contact of the relay, and the contactor coil of the backup power supply uses the normally closed contact of the relay.
When the main circuit has electricity, the relay is closed, the normally open contact is closed, and the main circuit is turned on. The normally closed contact is disconnected and the standby power supply does not work. When the main circuit is de-energized, the relay is also de-energized. The normally open contact returns to the initial disconnected state, and the main circuit is disconnected. The contactor of the standby circuit starts to work through the normally closed contact of the relay.
This is similar to the above, except that this relay is a double changeover contact. When energized, the two sets of contacts are closed. The two sets of contacts are closed when the power is off. One electrical component can be completed. If the A circuit is a single-phase 220 volt power supply, the coil voltage of the relay is also 220 volt AC.
This cost is a bit high and requires manual work. If you have a strong hands-on ability, you can assemble a control circuit yourself.
There must be a short time difference in power conversion, and it is impossible to achieve a seamless connection without interruption in the middle.
The difference between PC and CB dual power switch:
The dual power switch is divided into PC level and CB level, and the structure of the two is roughly the same. The PC level is isolated, just like a double-throw knife switch, plus an operating mechanism.
CB level is a circuit breaker protection type, consisting of two circuit breakers plus an operating mechanism, with overload and short circuit protection, just like circuit breaker protection. Users should consider the following aspects when choosing.
(1) Consider from the perspective of reliability.
The PC level is more reliable than the CB level. The PC level uses a mechanical + electronic conversion action lock, and the CB level uses an electronic conversion action lock. Therefore, in some workplaces with high security requirements, it is recommended to choose PC-level products.
(2) Consider from the perspective of switching time.
The switching time of the two products is different. PC-level products are commonly used in geared motors because the motor speed is high (16-22r/min). After the circuit breaks down, the switch action mechanism needs to be triggered after the motor speed is decelerated to a certain degree. On, the action time is relatively slow, although the switching time is slow, but as a mechanical product, it is more considered from the perspective of durability.
CB-level products are often used in residential buildings, and the faulty power supply is easy to disconnect and the switching time is fast.
(3) The PC-level dual power switch has no short-circuit protection function. Whether the user adds an additional circuit breaker should be considered according to whether the circuit system needs it.
The function of the dual power switch is to realize the conversion of dual power sources, and the short-circuit protection function will not affect its operation. Many people think that the short-circuit function is used to protect the switch, which is a misunderstanding and misunderstanding.
(4) The installation of isolating switches will take up space, increase costs, and reduce reliability. It is recommended that the number of isolating switches in industrial power systems should be controlled. It is not necessary to install isolating switches on residential floors.
Using the right switching method can greatly reduce equipment costs. Especially in sewage treatment projects, the dual power switch cabinet is an indispensable complete set of electrical equipment.
If you still don’t know much about dual power switching devices, you can contact ZHONGFEIYA TECH, a 30-year technical expert will answer for you.
