Elevator Brake Circuit With Sequential Segments for Smooth Emergency Stops
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Solution Overview
Problem
Conventional electromagnetic brake systems in elevators cause passenger discomfort due to abrupt deceleration during emergency stops, especially when the elevator car is lighter than the counterweight, leading to high deceleration rates and potential belt slippage, which are not adequately addressed by existing regulatory restrictions.
Innovation Solution
The implementation of a multiple-segment electromagnetic brake system with a snubber network that controls the sequential application of brake segments, using diodes, Zener diodes, resistors, capacitors, and coils in series or parallel to manage the deceleration rate, allowing for a smoother and controlled stop by delaying and softening the application of brake torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic brake system is engaged during power interruption, then emergency stop function is achieved, but passenger discomfort occurs due to abrupt deceleration
Solution Approach 1:
The brake system is divided into multiple independently controllable brake segments (first brake segment, second brake segment, third brake segment) that can be applied sequentially. Each brake segment has its own electromagnetic coil and snubber network, allowing the total brake torque to be distributed over time rather than applied all at once, thereby reducing abrupt deceleration while maintaining emergency stop capability.
Solution Approach 2:
The snubber networks (including diodes, capacitors, and resistors) are pre-configured in each brake segment circuit to automatically control the timing and sequence of brake application. When power interruption occurs, the snubber networks manage the decay of electromagnetic field in a controlled manner, initiating brake engagement with delayed and softened torque application rather than immediate full-brake engagement.
2Speed
If brake torque is applied quickly to stop elevator car, then stopping distance is reduced, but deceleration rate becomes too high causing belt slippage
Solution Approach 1:
The brake torque application is segmented into multiple phases corresponding to different brake segments being applied at different times. The first brake segment applies initial torque, followed by the second and third segments in sequence, creating a progressive torque build-up that limits peak deceleration rate and prevents belt slippage while still achieving the required stopping distance.
Solution Approach 2:
The brake segments are applied in a periodic sequence rather than simultaneously. Each brake segment has a predetermined response time controlled by its snubber network, creating a time-based periodic application pattern that distributes the braking action over multiple time intervals, thereby controlling the instantaneous deceleration rate.
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 solution ensures a smoother deceleration rate during emergency stops, reducing passenger discomfort and the risk of belt slippage, while meeting regulatory requirements for stopping 125% and 100% of the rated load, even in case of power interruptions.
Implementation Method 1
electromagnetic brake system with multiple independently controllable brake segments, each brake segment including an electromagnetic coil
Implementation Method 2
snubber network includes a capacitor in parallel with a diode
Implementation Method 3
snubber network includes a resistor in series with a diode
Implementation Method 4
each brake segment including an electromagnetic coil and a brake caliper, the brake caliper operable to apply a brake torque to a brake disc
Implementation Method 5
the brake caliper operable to apply a brake torque to a brake disc
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A brake system (30) for an elevator car (12) includes a multiple of brake segments (40A, 40B, 40C) for deceleration of the elevator car and a brake control circuit operable to control operation of each of the multiple of brake segments to passively sequence activation of each of the multiple of brake segments.