Relay Coil Control to Reduce Contactor Bounce in POW Switching
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Solution Overview
Problem
Existing switching devices face challenges in consistently and efficiently controlling the opening and closing of electric power connections, particularly in reducing electric arcing and current oscillations during point-on-wave (POW) switching.
Innovation Solution
The implementation of a relay device with an armature that moves between two contacts, driven by a relay coil and an additional coil, using a drive circuit to synchronize the additional coil with the relay coil, and employing a higher voltage source and constant current source to minimize inductance variability and ensure consistent switching times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a relay coil is used to drive the armature between contacts, then the switching device can be operated, but contactor bounce occurs due to non-instantaneous opening and closing
Solution Approach 1:
The additional coil is energized before the relay coil to pre-position the armature, reducing the impact and bounce when contacts close. This preliminary action prepares the system to minimize harmful effects during the main switching event.
Solution Approach 2:
The additional coil applies a counteracting force to the armature movement, opposing the bounce tendency before it occurs. By energizing the additional coil in coordination with the relay coil, the system creates a counter-force that reduces contactor bounce and improves switching consistency.
2Measurement precision
If point-on-wave switching is implemented to reduce electric arcing and current oscillations, then switching precision is improved, but device complexity increases due to multiple coils and synchronization requirements
Solution Approach 1:
The additional coil is coupled in series with the relay coil through a switch, merging their magnetic effects to achieve coordinated armature control. This series coupling simplifies the synchronization mechanism by electrically linking the two coils rather than requiring separate control circuits.
Solution Approach 2:
The drive circuit monitors the relay coil energization state and uses this feedback to control the switch that couples the additional coil. This feedback mechanism ensures the additional coil is energized at the precise moment needed for point-on-wave switching, achieving timing precision through automatic coordination.
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 solution enables more consistent and predictable operation of switching devices, reducing the likelihood and magnitude of electric arcing and current oscillations, while also extending the life of contacts and improving energy efficiency.
Implementation Method 1
a relay coil that receives a voltage to magnetize the relay coil, thereby causing the armature to move
Implementation Method 2
The electrical relay includes a first a coil and a second coil. A current is supplied to the coils and in opposite directions. The two coils and can be used to accelerate the armature in either direction in relation to the two contacts.
Data Source
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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.