For industrial control panels, electronic circuit breakers have some unique advantages over mechanical circuit breakers. The industrial control panel includes a set of circuits, including feeders, branches, control circuits, or two types of circuits that perform various specified functions.
In addition to the second class circuit, all other circuits need a fuse or a circuit breaker protection. For feeder and branch circuits, fuses or molded circuit breakers are the most common, and they can also be used in 24-volt DC control circuits.
With the development of electronic devices such as PLCs, sensors, and the like, electronic components are more sensitive to voltage dips and interrupts.
The standard method of protecting the 24 VDC circuit is to use a standard circuit breaker. If more than one circuit is needed, use a fuse or circuit breaker to split the power supply output according to the number of circuits.
One of the most basic requirements is that the fuses or circuit breakers used in the control circuit must follow the criteria for supplemental overcurrent protection. Some well-known standards like UL 1077 or UL 248-14 do not apply to electronic circuit breakers.
UL has established a new standard UL 2367-solid state overcurrent protection standard. This type of protector is used to isolate the transmitter, power supply or the load side of the battery, providing supplemental protection.
Traditional fuses or circuit breakers can be problematic when a fault or short circuit occurs in a standard fuse or circuit breaker that supplies power from the same power supply. All connection loads are voltage drop, depending on the damping of the short circuit. A mechanical circuit breaker or fused fuse takes some time before closing the affected circuit.
During this time, the voltage may drop to 0 volts for more than 10 milliseconds, causing the PLC to enter an unsafe or indeterminate state. If an electronic fuse (solid state overcurrent protector) is used, the overcurrent phenomenon will be more accurately diagnosed, and the closing speed will be much faster than the fuse or circuit breaker. This reduces the risk of a voltage close to zero.
Active current limit
In order to avoid these problems, advanced circuit breakers provide another viable solution. Different products have different characteristics, one design follows a thermo-magnetic curve, which behaves like a standard molded circuit breaker, but is based on electronic detection so faster and more accurate. These products can also handle large inrush currents (> 50.000 μF).
In addition, some circuit breakers can implement active current limiting, avoiding any voltage drop across the output circuit, so as not to affect the surroundings. Based on 100% personalized channel design and serial start function, large inrush current can be effectively managed without any problems or shutting down the phenomenon.
There is also an advanced design to avoid the output off due to a single channel failure (not the affected channel), and in fact such electronic circuit breakers are already available. The electronic measurement of each channel current allows the designer to reduce the installation power of the power supply, and no longer need to backup the power to deal with short circuit conditions. In addition, also has two-wire communication, remote reset, signal connection and other advantages.