Field-Winding Rotor Balance Using Coil End Cover Asymmetry
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Solution Overview
Problem
Wound-field rotating electric machines experience rotational imbalance due to uneven arrangement of electrical components around the rotor, leading to vibration and noise during rotation.
Innovation Solution
Incorporation of a coil end cover as a balance adjustment member to adjust weight balance in the circumferential direction, and use of holding members with varying weights between main pole portions to stabilize the rotor's rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrical components are arranged around the rotating shaft in the circuit module, then the rotor can rotate together with the circuit module, but uneven arrangement of electrical components causes weight differences in the circumferential direction resulting in rotational imbalance
Solution Approach 1:
The coil end cover is designed with an asymmetric structure where a balance adjustment portion is selectively removed in the circumferential direction. This creates asymmetric weight distribution that compensates for the uneven arrangement of electrical components in the circuit module, thereby achieving rotational balance while maintaining the ability to rotate with the circuit module.
Solution Approach 2:
The coil end cover features a localized balance adjustment portion that is selectively removed only in specific circumferential regions where weight compensation is needed. This local modification approach allows precise control over the weight distribution without affecting the overall structure or the circuit module's functionality.
2Adaptability or versatility
If electrical components are arranged around the rotating shaft in the circuit module, then the rotor can rotate together with the circuit module, but rotational imbalance occurs causing vibration and noise
Solution Approach 1:
The asymmetric removal of the balance adjustment portion from the coil end cover creates a counterbalancing effect that offsets the uneven weight distribution caused by electrical components. This reduces rotational imbalance, thereby minimizing vibration and noise generated during rotor rotation with the circuit module.
3Strength
If holding members are used to hold coil side parts of the field coil, then the field coil is secured, but weight balance adjustment is needed among holding members
Solution Approach 1:
The holding members are designed with differentiated weights, where at least one holding member has a different weight from others. This local variation in weight allows the holding members to both secure the field coil effectively and contribute to the overall rotational balance of the rotor by compensating for uneven weight distribution.
Solution Approach 2:
The holding members serve dual functions: they mechanically secure the coil side parts of the field coil to the rotor core, and simultaneously act as weight balancing elements through their differentiated weights. This multi-functionality eliminates the need for separate balancing components.
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
Ensures proper rotation of the rotor with the circuit module, reducing vibration and noise by achieving balanced weight distribution.
Implementation Method 1
the coil end cover is a balance adjustment member that adjusts weight balance of the rotor in the circumferential direction
Implementation Method 2
the wound-field rotating electric machine is configured to have harmonic current flowing through the stator coil to induce field current in the field coil
Implementation Method 3
a circuit module provided around a rotating shaft and connected with the field coil to form a resonant circuit together with the field coil
Implementation Method 4
the holding members are also balance adjustment members that adjust weight balance of the rotor in the circumferential direction, and at least one of the holding members that are aligned in the circumferential direction has a different weight from the remainder of the holding members
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A rotating electric machine (40) includes a stator (50) having a stator coil (52) and a rotor (60) having a rotor core (61) and a field coil (70). The rotating electric machine is configured to have harmonic current flowing through the stator coil to induce field current in the field coil. The rotor further has a circuit module (102) provided around a rotating shaft (32) and connected with the field coil to form a resonant circuit together with the field coil, and a coil end cover (103, 104) covering a coil end part (CE) of the field coil which is located axially outside the rotor core. Moreover, the coil end cover is a balance adjustment member that adjusts weight balance of the rotor in the circumferential direction; and at least part of the coil end cover in the circumferential direction constitutes an adjustment portion where weight of the coil end cover has been reduced or increased.