Month: September 2025

Electronic load-limiting automatic controller (hereinafter referred to as the controller) applies to AC 50Hz, operating voltage AC22OV control circuits, so that the system according to a predetermined power supply. When the electrical load exceeds the specified range of values, the controller automatically cut off the load power. When the load is restored to the set power value, the load power can be automatically connected, thus realising the automatic monitoring and control of the electrical load. The appearance of the controller adopts the DZ47 similar structure, and with the DZ47 small circuit breaker parallel installation supporting the use of. The panel is equipped with light-emitting diodes to indicate the monitoring of the controller’s working status: when the indicator is green, it means that the load power supply is connected to the operating state; when the indicator is red, it means that the load has been cut off, and the load limiting controller has been started to work.

Working Principle

Due to the small external size of the controller, coupled with the small internal load, RC resistor-capacitor buck is used to provide power to the controller. The capacitance parameter values are mainly determined according to the internal load of the controller. The main loads inside the controller include: internal high-power conversion relay (DC24V, P = O.93W), dual-colour LEDs, Ul55 chips, transistors and other devices. The high power relay has the highest load when it closes, and the relay closes with a current of 38mA when the load limiter is in operation. Plus light-emitting diodes and chips and other workload current 12mA, so the power supply to provide 50mA current can meet the normal operation of the controller.

The buck capacitor in this circuit mainly plays the role of capacitance XC to reduce the voltage and provide load current. The value of the capacitance XC can be obtained from (220V-24V)/50xIO3A =39200; where XC = l/ 2 πfC, the capacitance value C = l / 2πfX C is 0.81 μF, and according to the capacitance parameter series can be selected as 0.82 μF. When the controller is not in use, the drain resistor connected in parallel with it mainly serves as a drain channel for the capacitor. Resistance value is usually selected in 100 KΩ a 1M Ω, power 1W or more.

Here, 555 circuits can be generally summarised into three categories: monostable circuits, unstable circuits and bistable circuits in terms of application and mode of operation. The controller internal 555 circuit monostable to complete the work of load limiting. Usually in the 2-pin terminal for the “high level”, 3-pin terminal V uT = 0 is a steady state; when the 2-pin terminal for the “low level”, 3-pin terminal VOUT = 1 is a transient steady state, and transient steady state time t = 1.1x R12xC5 to determine.

How to wire a counting relay

The counting relay is used for counting. When the counting value reaches the preset value, the contact will be operated and an output will be provided. 1. There are two power cables, the DC one is divided into positive and negative poles. 2. There are two counting inputs, one pulse counts one time. 3. at least one pair of count to reach output contacts (1 normally open, 1 normally closed) 4. There is a reset input. (Used to reset the counter count) Since we do not know the specific model and manufacturer, the wiring pin can not be determined. You can check the information according to the model number. Principle of operation of undervoltage disconnectors for circuit breakersA practical novel electronic load-limiting automatic controller

Limit current controller: 1, the scope of application JSL integrated circuit fixed time limit current relay (hereinafter referred to as the relay), suitable for power network power supply lines, transformers, motors and other main equipment, and transmission and distribution systems as relay protection circuit appeared in the overload and short circuit protection. The product is a static multifunctional relay integrating start-up, delay, execution and signal indication, featuring high precision, low power consumption, accurate delay, high return coefficient, intuitive and convenient adjustment, large contact capacity, no need for independent operation power supply, etc. The product is suitable for overload and short circuit protection in power network supply lines, transformers, motors and other main equipment and transmission and distribution systems. The application of this product especially solves the compressed time level difference countermeasures requirements of the Ministry of Electric Power, overcomes the fatal weakness of the anti-time limit AC operation protection device and the fixed time limit protection of the power grid, and avoids the protection of the user’s faults caused by the overstep tripping and thus expanding the accident; the fixed time limit protection using the digital switch setting value, eliminates the original anti-time limit characteristics of relay in the fixed time calculation, the upper and lower levels of co-ordination and debugging, which brings a lot of tedious workload, greatly facilitates the operation of the static type multi-function relay. Eliminate the original inverse time characteristic relay, fixed value calculation, the upper and lower levels of cooperation and debugging brought about by a large number of cumbersome workload, greatly facilitating the design and field work of staff. It avoids the card phenomenon of GL series overcurrent relays and the deterioration in transport, and is an ideal replacement product for GL series relays.2 Main technical parameters3 Main technical parameters ●Overcurrent action value setting range: 2.0-9.9A; grade difference: 0.1A. ●Overcurrent action delay setting range: 0.05-9.99S; grade difference: 0.01S. ●Acid current breakage times Setting range: 2.0-8.0 times. 　　●Action time: the action time of current interrupter at any overcurrent setting value is not more than 50ms. ●Setting error: the error of current part at any setting value is not more than 2%+0.1A; the error at limit temperature is not more than 4%+0.1A; the delay error value of overcurrent delay is not more than 0.1%+10ms. ●Capacity of contacts: the contact capacity of the current interrupter at the voltage not more than 250V, the current not more than 5A, the level difference: 0.01S. ●Contact capacity: in the DC inductive load circuit with voltage not exceeding 250V, current not exceeding 5A and time constant of 5±0.75ms, the breaking capacity of the output contact of the product is 50W. The output contact can be reliably operated and returned to 5×104 times under the above specified load conditions. The long-term permissible switching current of the output contact is 5A. ● Thermal stability factor: 21n for long-term operation. 　　●Dielectric strength: The conductive terminals of the product are connected to the exposed non-electrically charged metal parts or between the shells, and can withstand 2000V (RMS) 50Hz AC voltage for 1 minute without any insulation breakdown or flashover phenomenon.

Functions of moulded case circuit breaker accessoriesPrinciple of operation of undervoltage disconnectors for circuit breakers

Moulded case circuit breaker has many kinds of auxiliary accessories, usually the most used is the shunt release, under-voltage release, these two are external accessories, need to be installed into the moulded case circuit breaker inside, moulded case circuit breaker itself with delayed release and instantaneous release function.
Function of shunt excitation disconnector: it can control the circuit breaker opening from a distance.
Function of undervoltage tripper: When the voltage is less than the rated voltage 70%-35%, the tripper will break the circuit breaker. Moulded case circuit breaker has many kinds of auxiliary accessories, usually the most used is the shunt release, under-voltage release, these two are external accessories, need to be installed inside the moulded case circuit breaker, moulded case circuit breaker itself with delayed release and instantaneous release function.
Function of shunt excitation disconnector: it can control the circuit breaker opening from a distance.
Function of undervoltage tripper: When the voltage is less than the rated voltage 70%-35%, the tripper will break the circuit breaker.

Automatic electronic load limiting controller