ESP Safety Brake Clutch for PM Motor Backdrive Locking
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Solution Overview
Problem
Existing ESP systems with permanent magnet motors face issues with shaft rotation during non-operational phases, leading to the generation of dangerous electric currents due to fluid flow, posing a risk of electric shock to personnel during installation, retrieval, and shutdown operations.
Innovation Solution
A safety brake device with a clutch mechanism that engages and disengages based on pressure differentials to prevent shaft rotation in ESP systems, using friction and key engagement to lock the shaft when fluid flow occurs, ensuring the system remains safe during non-operational phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a permanent magnet motor is used to drive the ESP system, then the system achieves higher efficiency and cooler operation, but dangerous levels of electric current can be generated when fluid forces the shaft to rotate during non-operational phases
Solution Approach 1:
The brake device is configured to automatically engage and prevent shaft rotation before fluid flow can generate dangerous currents. The brake mechanism is pre-positioned to counteract any rotational force that might occur during non-operational phases, eliminating the harmful effect before it can manifest.
Solution Approach 2:
The brake device acts as an intermediary between the permanent magnet motor and the fluid flow. It intercepts and prevents the conversion of fluid kinetic energy into electrical energy by blocking shaft rotation, thereby protecting personnel from electric shock while preserving the motor's efficiency benefits.
2Ease of operation
If the shaft is allowed to rotate freely during non-operational phases, then the system remains simple and easy to operate, but personnel are exposed to dangerous electric current generation
Solution Approach 1:
The brake device is designed to automatically engage and disengage based on system operational status without requiring manual intervention. During non-operational phases, the brake self-activates to prevent rotation; during operation, it self-disengages to allow free shaft rotation, maintaining simplicity while eliminating hazards.
Solution Approach 2:
The brake mechanism is pre-configured to engage automatically when the motor is not energized, preventing shaft rotation before personnel can be exposed to dangerous currents. This preliminary protective action occurs without requiring operational decisions or manual activation.
3Object-affected harmful factors
If a brake mechanism is added to prevent shaft rotation, then electric shock risk is eliminated, but device complexity increases
Solution Approach 1:
The brake device uses the presence or absence of motor power as a self-triggering signal. When power is absent, the brake automatically engages; when power is present, the brake automatically disengages. This self-service operation eliminates the need for complex control systems, sensors, or manual activation mechanisms.
Solution Approach 2:
The brake mechanism utilizes hydraulic or pneumatic principles where fluid pressure or elastic elements automatically activate the brake when motor power is removed. This passive activation method simplifies the control system while reliably preventing shaft rotation during non-operational phases.
4Object-affected harmful factors
If the brake engages automatically during fluid flow, then shaft rotation is prevented and safety is improved, but friction and energy loss increase during operation
Solution Approach 1:
The brake mechanism is designed to be dynamic rather than static, automatically transitioning between engaged and disengaged states based on motor operational status. During operation, the brake is fully disengaged to eliminate friction losses; during non-operation, it engages to prevent rotation and eliminate electric shock risk.
Solution Approach 2:
The brake applies counteracting force only when necessary—to prevent shaft rotation during non-operational phases. During normal operation, the brake is completely disengaged, allowing the shaft to rotate freely without friction interference, thus minimizing energy loss while maintaining safety.
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
The safety brake device effectively prevents shaft rotation and subsequent electric current generation, reducing the risk of electric shock by automatically engaging the clutch to lock the shaft during fluid flow, thus ensuring operational safety without additional intervention.
Implementation Method 1
a piston movable in response to a pressure differential across the piston
Implementation Method 2
A clutch engaged with the shaft is configured to restrict the rotation of the shaft
Data Source
AI summary
A device disclosed herein is used with an electric submersible pump (ESP) assembly disposed on tubing in a well. A housing of the device connects between tubing and pump. A shaft in the housing can rotate in response to imparted rotation associated with the pump and permanent magnet (PM) motor. A piston in the housing can move longitudinally relative to the shaft in response to a pressure differential across the piston. A clutch on the piston can engage and disengage with a distal end of the shaft in response to the piston's movement of the piston. Additionally or alternatively, a key on the piston can engage and disengage with a pocket on the shaft. The engagement of the clutch and/or key can prevent imparted rotation associated with the pump and the PM motor.