Ring Varistor Embedded in Commutator Counterbore
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Solution Overview
Problem
Large ring varistors required for large motors occupy excessive space, are prone to damage, and increase production and material costs, while existing installation methods are complex and costly.
Innovation Solution
Installing a ring varistor in a counterbore at the bottom end of the commutator eliminates the need for size increases, using a conductive sponge for contact with the commutator segment and tin-soldering for secure attachment, allowing for a compact design that reduces electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large ring varistor is used for large motors, then electromagnetic interference reduction is improved, but space occupation increases and interferes with motor end cover components
Solution Approach 1:
The ring varistor is nested within a counterbore cavity formed in the commutator body, allowing the varistor to be housed inside the existing commutator structure rather than mounting it on the external surface. This eliminates the need for additional space in the motor end cover while maintaining the EMI shielding function.
Solution Approach 2:
The solution transitions from a two-dimensional surface mounting approach to a three-dimensional embedded approach by creating a counterbore cavity. This allows the varistor to be positioned in the depth dimension of the commutator, removing the conflict with end cover space.
2Object-affected harmful factors
If a large ring varistor is used for large motors, then electromagnetic interference reduction is improved, but varistor damage risk increases and control requirements increase
Solution Approach 1:
By nesting the varistor within the counterbore, the structure provides mechanical protection and support from the surrounding commutator material, reducing the risk of damage during operation and handling.
Solution Approach 2:
The counterbore is pre-formed in the commutator to precisely accommodate the varistor, ensuring proper positioning and support before the varistor is installed. This preliminary structural preparation reduces installation complexity and control requirements.
3Object-affected harmful factors
If a large ring varistor is used for large motors, then electromagnetic interference reduction is improved, but material usage increases and cost increases
Solution Approach 1:
The embedded configuration allows for more efficient use of the varistor material by optimizing its placement within the counterbore, potentially reducing the overall size and material quantity needed compared to a surface-mounted large ring configuration.
4Reliability
If a ring varistor is tin-soldered to a lug of the commutator, then electrical connection is achieved, but installation complexity and control cost increase
Solution Approach 1:
The varistor installed in the counterbore can be electrically connected to the commutator segments through the counterbore structure itself or through simplified contact points, eliminating the need for separate lugs and complex tin-soldering procedures.
Solution Approach 2:
The counterbore structure itself can serve as the electrical connection path, with the varistor making direct contact with the commutator segments through the counterbore walls or bottom, eliminating the need for separate connection components and procedures.
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 saves space, simplifies the installation process, reduces material and production costs, enhances varistor strength, and effectively minimizes electromagnetic interference without increasing production control complexity.
Implementation Method 1
ring varistors are used to absorb electromagnetic interference generated by sudden switch-on and switch-off between a commutator and a brush of a motor
Implementation Method 2
A layer of conductive sponge is adhered to a silver layer of the ring varistor and the varistor adhered with conductive sponge is placed into the counterbore such that the conductive sponge contacts with a commutator segment
Implementation Method 3
The ring varistor placed in the counterbore is tin-soldered to the commutator segment
Data Source
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AI summary
A ring varistor-based method for reducing electromagnetic interference of a motor, a corresponding motor commutator, and the motor. The method comprises: forming a counterbore in an end of a motor commutator; and placing a ring varistor into the counterbore.