Home > Industry Information > Power Switch: Type Introduction And Selection Guide
A power switching switch is a power circuit switching device that switches the load line from one power source to another. Its important role is to ensure that the load is automatically
switched to the backup power supply when the main power supply fails, so as to maintain normal power supply usage.
Power switching switches are mainly applied in fields with high requirements for power supply continuity. For instance, commercial buildings, hospitals,
and communication base stations are all places with extremely high requirements for power supply.
· Hospitals: Critical areas such as operating rooms and intensive care units in hospitals have extremely high requirements for power supply. The power switching switch can quickly switch to
the backup power supply, such as the UPS battery pack or diesel generator, when the main power supply fails, ensuring the normal operation of medical equipment.
· Commercial buildings: The smooth operation of elevators in high-rise buildings relies on a stable power supply. The power switching switch can switch to the backup power supply
when the main power supply fails, ensuring the safe parking or continuous operation of the elevator.
· Communication base station: A communication base station requires a stable power supply to ensure the normal transmission of communication signals. The power switching switch can switch to the
backup battery pack when the mains power is cut off, ensuring the continuous operation of the base station.
Power switching switches can be classified into two types based on switching speed and application scenarios, namely static and automatic.
The following is a brief introduction to the characteristics of these two types of power switches.
The automatic transfer switch, abbreviated as ATS, is mainly used to provide the conversion of two power sources for the load. When an abnormal situation occurs with the main power supply,
it will be transferred to another (backup) power supply switchgear to ensure the continuous operation of the circuit load and normal power supply.
The automatic transfer switch is mainly used in emergency power supply systems.
The static switching switch, abbreviated as STS, is mainly composed of three parts: the intelligent control board, the high-speed perforated silicon, and the circuit breaker. It is a dual-input transfer switch.
During normal operation, one power supply is connected and the other is disconnected, with one AC input supplying power to the load. When the main power supply fails,
the static switching switch will automatically switch the load to the backup power supply to ensure the continuity of power supply, effectively avoiding equipment shutdown caused by power supply failure.
Both automatic toggle switches and static toggle switches are used as power switches in power supply systems. However, what are the differences between them?
The following is a brief analysis of the two aspects:
· Switching speed: The switching speed of an automatic switching switch is usually slower than that of a static switching switch, generally completed within a few seconds,
while the switching speed of a static switching switch can reach the millisecond level, which is extremely fast.
· Switching method: Automatic switching switches usually use mechanical contacts for switching, while static switching switches use electronic devices (such as thyristors) for switching.
Therefore, static switching switches do not cause mechanical wear during the switching process.
The grades of power switching switches are mainly divided into two levels: PC-level power switches and CB-level power switches. Their classification is based on functionality. For instance,
PC-level switching switches might be isolation type switching switches, while CB-level switching switches are protective switches for circuit breakers. Below, we will provide a more detailed
introduction based on their structural features and distinguish the differences between the two types of switching switches at the same time.
The PC-level power transfer switch is an isolation type, similar to a double knife switch combined with an operating system component. It does not have protection functions and its main body
is an isolation switch. Its function is to connect, carry, and have a high tolerance and connection capacity. It can protect the safety of the switch circuit, prevent damage due to overload or short circuit faults,
and ensure reliable connection of the circuit under such circumstances.
The CB-class power transfer switch is a circuit breaker protection type, consisting of two circuit breakers and an operating system section. It has overload and short-circuit protection functions,
with the main body being a circuit breaker.
The CB-class power transfer switch is a dual power supply equipped with an overcurrent trip unit. Its main contacts can connect and be used to break short-circuit currents,
featuring selective protection functions and providing short-circuit protection for the load and cables at the lower end.
As two types of power transfer switches, what are the differences between PC-level and CB-level? The following will analyze their structures, functions, and application scenarios:
·Structural composition: PC-level switches are isolated, with the main body being an isolating switch. The CB-class switch is of circuit breaker protection type, with the main body being a circuit breaker.
·Protection function: PC-grade switches have no overload or short-circuit protection functions. The CB-class switch is equipped with overload and short-circuit protection functions.
·Action time: The switching speed of PC-level switches is relatively fast, generally within tens of milliseconds. The switching speed of CB-class switches is relatively slow, usually taking several seconds.
·Application scenarios: PC-grade switches are suitable for places with high requirements for switching time and safety, such as operating rooms, and are more suitable for use in fire protection circuits.
Cb-class switches are suitable for ordinary circuits with low requirements for protection functions and switching time.
The requirements for different scenarios and devices vary. When choosing a power transfer switch, multiple factors need to be comprehensively considered for selection.
The following is an analysis of several aspects of factors:
·Sensitive loads: such as servers in data centers and medical equipment in hospitals, etc. These types of electronic devices are highly sensitive to power outages.
Even a brief interruption may lead to data loss or equipment damage. For this type of load, PC-level switches or static switching switches (STS) with fast switching speed should be selected to ensure the continuity of power supply.
·Non-sensitive loads: such as general lighting, air conditioning and other equipment, have relatively low sensitivity to power interruption and can accept a switching time of a few seconds.
For this type of load, a lower-cost CB-class switch can be selected.
·Overload and short-circuit protection: If the application scenario requires overload and short-circuit protection for the power supply to prevent equipment damage and safety accidents,
a CB-class switch with protection functions should be selected.
·No protection requirements: If the application scenario does not have high demands for protection functions and mainly focuses on switching speed and reliability, PC-level switches can be selected.
·Millisecond-level switching: When the application scenario requires almost uninterrupted switching to the backup power supply in the event of a power failure (such as data centers,
hospital operating rooms, etc.), PC-level switches or static switching switches (STS) should be selected. The switching speed of these devices is usually within a few milliseconds.
·Second-level switching: If the application scenario has a relatively low requirement for switching speed and can accept a few seconds of interruption time (such as general industrial equipment, commercial buildings, etc.),
then a CB-level switch can be selected.
Power transfer switches play a crucial role in power systems, mainly used to ensure that critical loads can quickly switch to the backup power supply when the main power supply fails,
thereby guaranteeing the continuity and stability of power supply. Whether it is a hospital operating room, a data center or a communication base station, these places with extremely high requirements
for power supply reliability all rely on power switching switches to avoid equipment downtime and data loss caused by power outages. By rationally selecting PC-level or CB-level switches,
and considering the characteristics of automatic transfer switches (ATS) and static transfer switches (STS), the reliability and stability of the power supply system can be ensured.
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