Relay Coil Circuit for Contactor Bounce and POW Switching
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Solution Overview
Problem
Switching devices in industrial and commercial settings face challenges in consistently and efficiently connecting and disconnecting electric power due to delays and arcing issues during point-on-wave (POW) switching, leading to torque oscillations and contact wear.
Innovation Solution
The implementation of a relay device with a relay coil and an additional coil connected in series, driven by a high voltage source and a constant current source, which minimizes inductance variability and reduces arcing by controlling the armature movement to optimize POW switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional relay coil operation is used, then the relay can operate with simple circuitry, but inductance variability causes inconsistent armature movement and contact bounce
Solution Approach 1:
An additional coil is introduced as an intermediary element connected in series with the relay coil. This additional coil acts as a mediator to compensate for inductance variability by providing a counteracting magnetic field that stabilizes the total inductance seen by the armature, thereby ensuring consistent armature movement and eliminating contact bounce without requiring complex external control circuitry
Solution Approach 2:
The invention changes the inductance parameter of the coil circuit by adding a second coil with specific inductance characteristics. The additional coil is designed with inductance that compensates for variations in the relay coil's inductance, maintaining a stable total inductance value that ensures consistent armature acceleration and positioning regardless of temperature or manufacturing variations
2Speed
If switching devices operate with delays, then the switching mechanism is simpler, but delays cause missed POW opportunities and increased contact wear
Solution Approach 1:
The additional coil is configured to energize simultaneously with or slightly before the relay coil, creating a preliminary magnetic field that begins accelerating the armature earlier. This preliminary action reduces the overall response time delay by pre-loading the magnetic field, enabling the switching device to catch and execute POW opportunities more reliably
Solution Approach 2:
The invention merges the functions of the relay coil and additional coil into a single series circuit configuration. Both coils work together in unison, with their magnetic fields combining to produce a more consistent and faster armature response. The series connection ensures that the same current flows through both coils, synchronizing their operation and eliminating the delays associated with sequential energizing
3Speed
If high voltage is applied to the relay coil, then the armature actuates faster, but arcing and contact wear increase
Solution Approach 1:
The additional coil creates a more gradual and periodic buildup of magnetic field strength when combined with the relay coil. The series connection causes the magnetic field to develop more smoothly over time rather than as a sudden spike, reducing the shock loading and arcing that occurs with abrupt high-voltage application while still achieving fast armature actuation
Solution Approach 2:
The invention converts the potential harm of high voltage into a benefit by using the additional coil to distribute the voltage stress. The series connection divides the applied voltage between the relay coil and additional coil, reducing the voltage across each individual coil and thereby minimizing arcing and contact wear while maintaining the overall high-voltage drive needed for fast actuation
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
This approach enables more consistent and efficient POW switching, reducing delays and arcing, thereby improving the reliability and longevity of switching devices by ensuring consistent operation across various coil resistances and temperatures.
Implementation Method 1
a relay coil that receives a voltage to magnetize the relay coil, thereby causing the armature to move
Implementation Method 2
an additional coil that couples in series with the relay coil via a switch... minimizes inductance variability
Data Source
AI summary
A relay device may include an armature that moves between a first position that electrically couples the armature to a first contact and a second position that electrically couples the armature to a second contact. The relay device may also include a relay coil that receives a voltage to magnetize the relay coil, thereby causing the armature to move from the first position to the second position. The relay device also includes an additional coil that couples in series with the relay coil via a switch. The relay device also includes a drive circuit that causes the switch to couple the additional coil to the relay coil in response to receiving a signal indicative of the relay coil energizing.