Drive Train Starting via Differential Gear Segmentation
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Solution Overview
Problem
Existing drive systems, particularly those using three-phase machines, face challenges in achieving high starting torque efficiently due to low starting torque and high electrical load, leading to oversized machines and inefficiencies, while differential systems offer limited speed ranges and torque delivery.
Innovation Solution
A method involving a differential gear system with a simple planetary gear stage and a synchronization brake, allowing the drive machine to be connected to the network in phases to achieve high torque from zero speed, with the differential drive compensating for speed differences and controlling torque delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If three-phase machines are used for drive, then electrical power consumption is high, but starting torque is low and network load is excessive
Solution Approach 1:
The drive system is segmented into two independent drives: a main drive machine (three-phase motor) and a differential drive machine. The differential drive machine handles the starting phase independently, allowing the main drive to be optimized for continuous operation without being oversized for starting requirements.
Solution Approach 2:
The differential drive machine performs the preliminary action of accelerating the driven machine from zero speed to a speed where synchronization becomes possible. This preliminary acceleration phase resolves the starting torque limitation of three-phase machines without requiring excessive electrical power.
2Power
If three-phase machines are designed with large size to deliver nominal torque from standstill, then starting torque is sufficient, but the machine is oversized and inefficient
Solution Approach 1:
The drive function is segmented between two machines: the differential drive machine handles starting and speed variation, while the main drive machine handles continuous nominal operation. This allows both machines to be optimally sized for their specific functions rather than one machine being oversized for all conditions.
Solution Approach 2:
The differential drive machine serves multiple functions: providing starting torque, enabling speed variation, and facilitating smooth synchronization with the main drive. This multi-functionality eliminates the need for an oversized single machine.
3Loss of energy
If differential systems are used for variable-speed operation, then efficiency is improved, but speed range is limited and low speeds are not reachable
Solution Approach 1:
The differential drive machine performs preliminary acceleration from zero speed before the main drive takes over. This preliminary action enables the system to reach the minimum speed required for differential mode operation, expanding the overall speed range while maintaining efficiency.
Solution Approach 2:
The system dynamically transitions between different operating modes: initially using only the differential drive for low-speed operation, then progressively engaging the main drive as speed increases. This dynamic operation allows the system to access low speeds while maintaining high efficiency across the entire speed range.
4Ease of manufacture
If differential drive is dimensioned smaller than main drive, then cost is reduced, but torque delivery is limited
Solution Approach 1:
The differential drive machine performs preliminary acceleration during the starting phase when full torque is required. Once the driven machine reaches sufficient speed, the main drive takes over torque delivery. This temporal separation allows the differential drive to be smaller while still providing adequate starting torque.
Solution Approach 2:
The system ensures continuous useful action by smoothly transitioning from differential drive to main drive. The differential drive operates at full capacity during starting, then gradually transfers the load to the main drive, maintaining continuous torque delivery throughout the acceleration process.
Data Source
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AI summary
In a method and a drive for starting a drive train, with a drive shaft (2), a drive motor (4) connected to an electrical grid (12) and with a differential gearing (3) with three drives and outputs, wherein one output is connected to the drive shaft (2), a first drive is connected to the drive motor (4) and a second drive is connected to a differential drive (5), the drive motor (4) is started from a rotational speed of zero or approximately zero while an external braking torque acts on the drive shaft (2), and the second drive is braked in an acceleration phase of the drive shaft (2).