Locomotive Traction Motor Field Isolation System
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Solution Overview
Problem
Existing traction motor systems in locomotives are susceptible to large-scale failures when one motor fails, leading to the disablement of all motors in the same circuit, and current isolation methods often remove both armature and field winding components, which can be unnecessary and reduce system functionality.
Innovation Solution
A traction motor drive system with a field isolation system that includes shunt circuits and switches to selectively isolate faulty field circuits, allowing the armature to remain operational and maintain dynamic braking capabilities, while isolating only the defective field circuit from the rest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If motors are connected in series or parallel with multiple other motors to share a common electrical bus, then wiring and electric control are simplified, but the system becomes susceptible to large-scale drive system failure where one motor failure can disable all other traction motors in the circuit
Solution Approach 1:
The patent divides the traction motor circuit into multiple independent parallel circuits, where each circuit contains one or more motors. This segmentation ensures that a failure in one circuit does not propagate to other circuits, maintaining system reliability while preserving wiring simplicity through the common electrical bus architecture.
Solution Approach 2:
The patent introduces isolation switches as intermediary components between motors and the common electrical bus. These switches act as mediators that can selectively disconnect faulty motors from the circuit, preventing failure propagation while maintaining the simplified common bus wiring structure.
2Reliability
If an isolation switch is used to remove a failed motor from the circuit, then the remaining motors remain operational, but both the armature and field winding are removed together, unnecessarily eliminating functional components
Solution Approach 1:
The patent segments the motor into two independently isolatable components: the armature circuit and the field winding circuit. Each component has its own isolation switch, allowing selective disconnection of only the faulty component while preserving the functional component's ability to contribute to system operations including dynamic braking.
Solution Approach 2:
The patent applies different isolation strategies to different parts of the motor based on their functional requirements. The field winding isolation switch and armature isolation switch enable localized isolation of only the defective component, preserving the local quality and functionality of the remaining component for continued system operation.
Data Source
AI summary
A traction motor drive system includes a plurality of armatures arranged in parallel with each other and a plurality of field circuits arranged in series with one another. The plurality of field circuits is arranged in parallel with the armatures. The traction motor drive system also includes a field isolation system including a shunt circuit associated with at least one field circuit. The field isolation system includes a first field switch arranged in series with the plurality of field circuits and configured to switch between a first terminal of the shunt circuit and a first field terminal of at least one field circuit. The field isolation system includes a second field switch, arranged in series with the plurality of field circuits and configured to switch between a second terminal of the shunt circuit and a second field terminal of at least one field circuit.