Circuit Breaker Trip Coil Delay for Pole Switching Synchronization
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Solution Overview
Problem
Existing circuit breakers face challenges in achieving synchronized switching times across breaker poles while maintaining limited power consumption and ensuring functionality during voltage fluctuations, as traditional methods to adjust tripping times are either ineffective or risk impairing synchronization.
Innovation Solution
Incorporating an electrical delay element into the tripping circuit of a circuit breaker, such as a delay coil or capacitor, to reduce the steepness of current increase and delay the magnetic field generation, thereby increasing the tripping time without significantly affecting the force on the tripping element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the tripping time is reduced to achieve shorter switch response time, then the switching speed is improved, but the power consumption increases beyond acceptable limits
Solution Approach 1:
The patent applies preliminary action by pre-charging a capacitor through a resistor before the tripping event. The capacitor is charged in advance during normal operation, and when tripping is required, the stored energy in the capacitor is discharged through the tripping coil, providing an immediate current boost without requiring continuous high power consumption from the power supply.
Solution Approach 2:
The patent changes the electrical parameters of the tripping circuit by introducing a capacitor and resistor that dynamically alter the current characteristics. The capacitor provides a transient current surge with high initial amplitude that decays over time, effectively changing the current waveform from a steady state to a transient pulse, thereby achieving fast tripping with reduced average power consumption.
2Adaptability or versatility
If additional components are added to adjust tripping time for synchronization, then the tripping time adjustability is improved, but the device complexity increases
Solution Approach 1:
The patent uses parameter changes by varying the resistance value in the RC circuit to achieve different tripping time delays. By selecting different resistor values, the time constant (τ = RC) of the circuit changes, thereby adjusting the tripping time to synchronize multiple breaker poles without requiring complex electronic control systems.
Solution Approach 2:
The patent introduces a resistor as an intermediary component between the power supply and the tripping coil. This resistor acts as a simple, passive element that controls the charging rate of the capacitor and consequently the timing of the tripping event, providing an elegant and low-complexity solution for synchronization.
3Adaptability or versatility
If the current increase steepness is reduced to extend tripping time, then the synchronization capability is improved, but the magnetic field generation is delayed
Solution Approach 1:
The patent exploits the phase transition in the capacitor's charging process. The capacitor charges exponentially through the resistor, creating a natural time delay. When the capacitor voltage reaches the tripping threshold, it rapidly discharges through the tripping coil, generating a sharp current rise and immediate magnetic field. This phase transition from gradual charging to rapid discharging resolves the contradiction between delayed magnetic field generation and synchronization capability.
Solution Approach 2:
The patent creates a periodic-like action in the circuit by having the capacitor charge and discharge in cycles. The charging phase provides the delay needed for synchronization, while the discharging phase provides the sharp current rise for immediate magnetic field generation. This periodic charge-discharge cycle effectively separates the timing function from the actuation function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for adjustable and flexible tripping time extension, enabling synchronized switching across breaker poles and maintaining functionality during voltage variations without increasing power consumption or altering the switching speed.
Implementation Method 1
A current flowing in the tripping coil generates a magnetic field that effects the movement of the tripping element
Implementation Method 2
an electrical delay element that is able to be connected to the tripping circuit and reduces a steepness of a current increase of a current flowing in the tripping coil after the tripping circuit has been closed and/or delays a current increase
Data Source
AI summary
A trip device for a power circuit breaker has a trip element, a trip circuit with a trip coil, which, when energized, is configured to effect a movement of the trip element, and at least one electrical delay element, which can be connected to the trip circuit and reduces the rate of a rise in a current flowing in the trip coil once the trip circuit has been closed and/or delays a rise in a current flowing in the trip coil once the trip circuit has been closed.