Electric Step Motor Braking Circuit for Silent Light Fixture Power Down
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Solution Overview
Problem
Existing braking systems for electric step motors in light assemblies do not effectively reduce movement speed and prevent electronic disturbances during power down situations, leading to noise and potential damage to electronic components.
Innovation Solution
The implementation of switches that connect the step motors to establish a current path through motor windings during power down, using either relay or semiconductor switches, with current regulation means to control the current and voltage, ensuring a controlled and silent braking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the step motors are disconnected from driving means during power down, then the motors can stop quickly, but the moving head light fixtures will generate noise and electronic disturbances
Solution Approach 1:
The patent converts the harmful effect of back-EMF generated during motor deceleration into a beneficial braking force. By connecting the motor terminals through switches to form closed loops, the back-EMF induces currents that create magnetic forces opposing the rotor motion, providing electromagnetic braking that reduces noise and electronic disturbances while controlling the movement speed during power down
Solution Approach 2:
The patent dynamically changes the circuit configuration during power down by switching from the operational connection to a braking connection. The switches transition the motor windings from being connected to the driving means to being connected in closed loops, creating a dynamic braking circuit that adapts to the power down state and provides controlled deceleration without noise
2Device complexity
If the motor windings are left open during power down, then the circuit is simple, but high voltage is generated that can damage semiconductor components
Solution Approach 1:
The patent prepares the braking circuit in advance by providing switches that can quickly reconfigure the motor connections during power down. The switches are positioned and configured so that when power is interrupted, they automatically or rapidly switch the motor terminals to the braking connection, establishing protective closed loops before damaging voltages can develop
Solution Approach 2:
The patent introduces switches as intermediary components between the motor windings and the external circuit. These switches act as mediators that redirect the back-EMF energy into safe closed loops during power down, preventing the generation of damaging high voltages while maintaining circuit simplicity through automated switching
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 allows for slow and noiseless movement of light fixtures during power down, protecting electronic circuits from overvoltage and enabling safe handling and transportation by establishing a braking circuit that regulates current and voltage.
Implementation Method 1
the rotating motors will generate current in their windings which can generate a relatively high voltage somewhere in an electric circuit
Implementation Method 2
the switches establish a current path through at least one motor winding
Data Source
AI summary
A braking system for electric step motors that operate in conjunction with a light assembly, including a moving head for pan or tilt thereof or for moving internal optical components. The step motors are connected to driving means to reduce movement speed of the moving head during power down and are connected through switches with a first operating position to connect the driving means to the step motors, and with a second power down position to establish a current path through a motor winding. Movements after power down take place very slowly and without generating noise for use in a theatre where the lamp may be switched off because a fuse burn out, and so cease operation without making disturbing noise. In a controlled power down, noise is reduced when several lamp fixtures placed side by side at the same time move to a stop position.