Compact Current Transformer Module with Cup-Shaped Base
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Solution Overview
Problem
Current transformer modules require significant space on circuit boards to meet legal clearance and creepage distance requirements, especially when measuring high currents, making them unsuitable for compact installations.
Innovation Solution
A compact current transformer module design featuring a cup-shaped base with a toroidal core winding and insulated primary circuit wire routed along the outer wall, maintaining clearance and creepage distances without increasing the module's spatial extent, using double insulated wires and additional insulation layers for high current-carrying capacity and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current transformer is designed to meet legal clearance and creepage distance requirements, then safety and reliability are improved, but the space required on the circuit board increases
Solution Approach 1:
The patent utilizes the third dimension by routing the primary circuit wire along the outer wall surface of the cup-shaped base rather than keeping it flat on the circuit board plane. This vertical routing approach allows the wire to gain additional spatial clearance without increasing the footprint area on the circuit board, thereby maintaining compliance with clearance and creepage distance requirements while minimizing the space occupied.
Solution Approach 2:
The current transformer components are nested within the cup-shaped base structure. The toroidal core winding is positioned inside the base, the primary circuit wire is routed along the outer wall, and the insulation layer is applied to the wire. This nested arrangement consolidates all components into a compact configuration that meets safety distances while minimizing the overall space requirement on the circuit board.
2Power
If conductor tracks on the circuit board are made wider to carry high currents, then current-carrying capacity is improved, but the space required increases due to clearance and creepage distance requirements
Solution Approach 1:
Instead of increasing the width of conductor tracks on the circuit board, the patent routes the primary circuit wire along the outer wall of the cup-shaped base, utilizing the vertical dimension. This approach allows high current-carrying capacity to be achieved through the wire's cross-sectional area rather than track width, avoiding the need for additional space to maintain clearance and creepage distances.
Solution Approach 2:
The patent extracts the high-current carrying function from the circuit board conductor tracks and relocates it to the primary circuit wire that is routed along the outer wall of the base. This separation allows the circuit board to use standard-width tracks while the wire, which is not constrained by board space, carries the high current with appropriate insulation and clearance.
3Area of stationary object
If the current transformer module is made more compact to save space, then space efficiency is improved, but maintaining legal clearance and creepage distances becomes more difficult
Solution Approach 1:
The patent achieves compactness by routing the primary circuit wire along the outer wall of the cup-shaped base, utilizing the vertical dimension rather than horizontal space. This dimensional change allows the module to maintain a small footprint on the circuit board while simultaneously ensuring that the wire maintains the required clearance and creepage distances from other components through its elevated position on the outer wall.
Solution Approach 2:
The patent applies a three-layer insulation layer specifically to the primary circuit wire at critical locations where clearance and creepage distances must be maintained. This localized enhancement of insulation quality ensures compliance with legal requirements at specific points without requiring the entire module to be enlarged, thus maintaining compact dimensions while ensuring reliability.
4Reliability
If a three-layer insulation layer is applied to the wire, then insulation strength and safety are improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The three-layer insulation is applied to the primary circuit wire during the manufacturing process before the wire is installed in the final assembly. This preliminary application of insulation simplifies the overall manufacturing process by consolidating the insulation step into an early stage, avoiding the need for additional insulation operations during final assembly, and ensuring that the wire is already protected when installed in the cup-shaped base.
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 design allows for a space-saving current transformer module that meets legal requirements while ensuring high current-carrying capacity and low temperature sensitivity, with enhanced insulation and mechanical protection, enabling precise current measurement in limited spaces.
Implementation Method 1
a toroidal core winding with connections forming a secondary circuit of the current transformer is arranged, an insulated wire forming a primary circuit of the current transformer being guided through the toroidal core winding
Data Source
Figure 1
Figure 2
AI summary
The module (10) has a socket (20), in which a circular core winding (11) with connectors (18, 18') is arranged. The socket is designed in a bowl type, and a base plate (201) comprises a broad side (202) and narrow sides (203, 203'). A primary circuit-wire (12) i.e. dual wire, is guided from a free end (14) till to an entry location (16) at the broad side and from an exit location to another free end at another broad side. The connectors are guided away via connection wires (19, 19') from the socket, where the connection wires are connected with a circuit board at a distance from the socket.