Current Sense Transformer Opposing Windings for Accurate Breaker Sensing
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Solution Overview
Problem
Circuit breaker devices in industrial automation environments face issues with excess wire length and gauge in transformer windings, leading to thermal dissipation, impedance, and space constraints, which can cause voltage isolation and inaccuracies due to core saturation or underutilization.
Innovation Solution
The use of primary winding turns in opposing directions in current sense transformers to magnetically cancel each other out, allowing for a desired turns ratio without excess wire length, thereby addressing thermal and impedance issues while optimizing space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gauge of conductive wires is decreased to increase impedance, then short circuit let-though energy is reduced, but thermal issues occur and sensing circuitry overheats
Solution Approach 1:
The primary winding is segmented into two separate windings with opposite polarities instead of using a single wire with excessive length. This segmentation allows the wire gauge to be optimized for current carrying capacity while achieving the desired impedance through the differential winding configuration rather than excessive wire length.
Solution Approach 2:
The invention changes the configuration parameter of the primary winding from a single-direction winding to opposite-polarity windings. This parameter change allows the impedance to be controlled by the winding configuration rather than wire length, enabling the use of thicker wires that can handle thermal loads while maintaining proper impedance for short circuit protection.
2Reliability
If the length of wire in primary winding is increased to achieve desired impedance, then short circuit let-though energy is reduced, but thermal dissipation increases and space constraints are violated
Solution Approach 1:
The primary winding is divided into two separate windings with opposite polarities. This segmentation allows the achievement of desired impedance through the differential configuration of these windings rather than using excessive wire length, thereby reducing the space required in the transformer core and eliminating thermal dissipation issues associated with long wire runs.
Solution Approach 2:
The invention changes the winding configuration parameter from single-direction to opposite-polarity windings. This parameter change enables impedance control through configuration rather than length, allowing the use of shorter wire segments that fit within space constraints while maintaining the necessary impedance for proper short circuit protection.
3Reliability
If the length of wire in primary winding is increased to achieve desired impedance, then short circuit let-though energy is reduced, but thermal dissipation increases
Solution Approach 1:
The primary winding is segmented into two windings with opposite polarities, allowing the desired impedance to be achieved through the differential configuration rather than excessive wire length. This segmentation reduces the total wire length and associated resistive losses, thereby reducing thermal dissipation while maintaining short circuit protection capability.
Solution Approach 2:
The invention changes the winding configuration from single-direction to opposite-polarity windings. This parameter change allows impedance to be controlled by the winding arrangement rather than wire length, enabling the use of shorter wires with lower resistance that dissipate less thermal energy while maintaining the necessary impedance for short circuit protection.
4Reliability
If excessive wire length is used in primary winding, then desired impedance is achieved, but voltage isolation inaccuracies occur due to core saturation or underutilization
Solution Approach 1:
The primary winding is segmented into two windings with opposite polarities, which prevents core saturation by balancing the magnetic flux. This segmentation ensures that the core operates within its linear region, maintaining measurement precision and preventing inaccuracies that would result from core saturation or underutilization while achieving the desired impedance.
Solution Approach 2:
The invention changes the winding configuration to opposite-polarity windings, which alters the magnetic flux distribution in the core. This parameter change prevents core saturation by canceling out opposing flux components, ensuring the core operates in its linear region and maintaining measurement precision for accurate current sensing.
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 ensures compliance with thermal and short-circuit let-through energy standards, eliminating space constraints and maintaining accurate current measurement, thus protecting loads from overcurrent and short circuits effectively.
Implementation Method 1
The number of primary winding turns includes a first number of primary winding turns in a first direction and a second number of primary winding turns in an opposite direction that magnetically cancel out the second number of primary winding turns in the first direction to generate an effective number of primary winding turns
Implementation Method 2
The current flowing through the primary winding around the core creates a magnetic field. This magnetic field is transferred across the magnetic core to the secondary windings, which convert the magnetic energy back into electrical energy
Data Source
AI summary
The present technology relates to circuit breaker devices having current sense transformers. The current sense transformer includes a core, a secondary winding, and a primary winding coupled to the power input. The secondary winding includes a first wire wrapped around the core a number of secondary winding turns. The primary winding includes a second wire wrapped around the core a number of primary winding turns. The number of primary winding turns includes a first number of primary winding turns in a first direction and a second number of primary winding turns in an opposite direction that magnetically cancel out the second number of primary winding turns in the first direction to generate an effective number of primary winding turns. The effective number of primary winding turns and the number of secondary winding turns make up a desired turns ratio.