Rotating Machinery Circulating Current Restraining Winding
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Solution Overview
Problem
In large rotating machinery, increasing the number of parallel armature winding circuits to reduce current and heat leads to unbalanced currents and circulating currents, resulting in increased losses and coil temperature rises, which can damage insulation and decrease efficiency.
Innovation Solution
A rotating machinery design with a 2n-pole rotor and 72n stator slots, where each stator slot houses a top and bottom coil, forming 2n phase belts with specific alternating arrangements of first and second parallel windings to minimize circulating currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the number of parallel circuits is increased to reduce current and heat, then current per armature winding is reduced and temperature rise is mitigated, but currents become unbalanced and circulating current arises
Solution Approach 1:
The patent changes the connection configuration parameters of the armature windings by introducing a specific circulating current restraining winding with a defined number of turns and connection method. This parameter change allows the system to operate with multiple parallel circuits while restraining circulating current and reducing energy loss.
Solution Approach 2:
The circulating current restraining winding acts as an intermediary element that is introduced into the armature winding system. This additional winding serves as a mediator to balance the currents across parallel circuits by providing a counteracting magnetic field that restrains the harmful circulating current.
2Use of energy by moving object
If the number of parallel circuits is increased to reduce current per armature winding, then heat generation is reduced, but circulating current arises and coil temperature rises
Solution Approach 1:
The patent modifies the electrical parameters of the armature winding system by adding a circulating current restraining winding with specific turn ratios and connection configurations. This parameter change enables the system to maintain balanced current distribution across multiple parallel circuits, preventing temperature rise despite increased parallel circuit count.
Solution Approach 2:
The circulating current restraining winding serves as an intermediary component that mediates the current distribution across parallel circuits. By introducing this additional winding with appropriate connection methods, the system achieves balanced current flow and prevents harmful circulating current that would otherwise cause temperature rise.
3Loss of energy
If circulating current is restrained by changing coil connection combinations, then loss of armature windings is reduced, but the number of jumper connections increases
Solution Approach 1:
The patent optimizes the connection parameters of the circulating current restraining winding, specifically setting the number of turns to a value between 0.05 to 0.5 times the series armature winding turns. This parameter optimization achieves effective circulating current restraint while minimizing the increase in jumper connections and overall device complexity.
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 configuration reduces circulating current and armature winding losses, enhancing efficiency and preventing insulation damage by balancing current distribution across the windings.
Implementation Method 1
electro-magnetic force and heat generated by armature windings
Implementation Method 2
electro-magnetic force and heat generated by armature windings
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Rotating machinery includes a 2n-pole rotor (100), a stator core (10) with 72n slots (50), and three-phase armature windings (n is integer and ≥1). Each of the armature windings has 2n phase belts (60) per phase. Each of the phase belts (60) includes a first parallel winding and a second parallel winding. The first and second parallel windings are arranged in the stator slots (50) as top coils (20) and bottom coils (30). Assuming that a circumferential mean position of all top coils (20) and bottom coils (30) included in each of the phase belts (60) is defined as a phase belt center (60a), an arrangement of the first and second parallel windings in at least one phase belt (60), as viewed in an order of proximity to the phase belt center (60a), is such that the first and second parallel windings are arranged in an order of the second, first, second, first, first, second, first, second, first, second, second, and first parallel windings as the top coils (20), and the first and second parallel windings are arranged in an order of the first, second, second, first, second, first, first, second, first, second, second, and first parallel windings as the bottom coils (30) connected to the top coils (20).