Magnetic Ring Reduces Short-Circuit Torque in Magnet Motors
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Solution Overview
Problem
Conventional magnet motors with multiple redundant units face increased mass, size, and cost due to high short-circuit torque, which complicates motor sizing and induces braking forces, especially when one motor fails, leading to inefficiencies and performance degradation.
Innovation Solution
Incorporating a ring of magnetic material around the rotor within the stator housing increases the motor's inductance, reducing maximum short-circuit torque without altering the motor's structure or production tools, thus maintaining cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motors are sized to compensate for braking force from faulty motors, then reliability is improved, but weight increases
Solution Approach 1:
The patent changes the electrical parameters of the motor by adding resistance to the coils, which increases the rotor speed at which maximum torque occurs. This parameter modification allows the motor to produce sufficient torque at higher speeds, compensating for the braking force from faulty motors without requiring oversized motors, thus reducing weight while maintaining reliability
2Object-affected harmful factors
If coil resistance is increased to limit short-circuit torque, then short-circuit torque is reduced, but Joule heating losses increase
Solution Approach 1:
The patent modifies the motor's operational parameters by increasing coil resistance, which shifts the torque-speed characteristic curve. This allows the motor to operate at higher speeds where the same resistance produces less harmful short-circuit torque, while the increased speed operation compensates for the energy losses through improved overall efficiency
3Reliability
If motors are oversized to handle braking force, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent simplifies the motor sizing process by fundamentally changing the torque-speed characteristics through increased coil resistance. This parameter change allows standard-sized motors to inherently handle fault conditions without requiring complex oversizing calculations, reducing device complexity while maintaining fault tolerance
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 results in a lighter, less bulky drive device with reduced short-circuit torque, allowing for efficient operation and minimizing the need for oversized motors, thereby enhancing performance and reducing manufacturing costs.
Implementation Method 1
the magnetic ring increases the motor's inductance, thereby reducing the maximum short-circuit torque
Implementation Method 2
The rotor 2 is provided with at least one ring 6 of magnetic material which adjoins said section 5
Data Source
Figure 1~5
AI summary
A magnet motor, comprising a stator (1) formed from a laminated core provided with windings to form phases and a rotor (2) provided with magnets (4) distributed angularly around at least one section (5) of the rotor and pivotably received in the housing (3) of the stator. The stator has a length greater than a length of said section of the rotor and the rotor is provided with at least one ring (6) made from magnetic material that adjoins said section and is received in the housing of the stator. A drive device comprising a plurality of motors and a method for producing such a motor.