Capacitive Motor Assembly for Stage Light Power-Failure Braking
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Solution Overview
Problem
Stage light fixtures experience high-speed falls during power failures due to lack of braking force, leading to potential damage from impact, as existing braking methods like brake motors and short-circuiting of stepper motors are either costly or insufficient for heavy components.
Innovation Solution
A motor assembly comprising an automatic transfer switch, a capacitive load, and an alternating current motor, where the windings are connected to the motor driver when energized and switched to a capacitive load during deenergization, generating a longitudinal magnetization armature reaction to increase induced voltage and current, thus enhancing braking torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a brake motor is used to brake the rotary shaft during power failure, then the braking force is sufficient to prevent high-speed falling, but the device complexity and cost increase
Solution Approach 1:
The patent introduces a capacitive load as an intermediary element between the motor windings and the power source. During power failure, the capacitive load serves as a mediator to generate the necessary braking torque through induced current, avoiding the need for complex brake motors while achieving sufficient braking force
Solution Approach 2:
The patent replaces the mechanical brake motor system with an electromagnetic braking mechanism. By utilizing the motor's own windings and a capacitive load to generate electromagnetic braking torque, the system eliminates the need for separate mechanical braking components, thereby reducing device complexity while maintaining adequate braking capability
2Force
If a brake motor is used to brake the rotary shaft during power failure, then the braking force is sufficient to prevent high-speed falling, but the manufacturing cost increases
Solution Approach 1:
The patent employs a capacitive load, which is a relatively inexpensive component compared to a brake motor. The capacitor can be easily manufactured and replaced if necessary, providing an cost-effective solution for generating braking torque during power failures without requiring expensive specialized braking hardware
Solution Approach 2:
The patent makes the motor windings multi-functional by using them both for normal motor operation and for generating braking torque during power failures. This eliminates the need for dedicated braking components, reducing overall system cost while maintaining sufficient braking capability through the same existing motor structure
3Device complexity
If two pairs of windings of a two-phase stepper motor are short-circuited via a relay during power failure, then the motor generates braking force through induced current, but the braking torque is too small for heavy components
Solution Approach 1:
The patent changes the electrical parameters by introducing a capacitive load into the motor circuit during power failure. This parameter change transforms the motor into a generator mode where the capacitive load creates a phase shift that enhances the induced current and generates sufficient braking torque to handle heavy components, overcoming the limitation of simple short-circuit braking
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 solution effectively reduces the falling speed of stage light fixtures during power failures by increasing braking torque, protecting the components from impact damage and ensuring smoother braking without the limitations of existing methods.
Implementation Method 1
the motor is driven to rotate by falling of the components, so that the motor generates an induced current formed by an induced electromotive force
Implementation Method 2
the capacitive load makes the phase of the induced current 90° ahead of the phase of the induced voltage
Implementation Method 3
the directions of the electromotive forces generated by the armature magnetic field of the motor and the primary magnetic field of the permanent magnet are consistent, and a longitudinal magnetization armature reaction thus may be generated
Data Source
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AI summary
The present disclosure relates to the technical field of power electronics, and provides a motor assembly for slowing down falling speed of a stage light fixture on power failure, and a stage light fixture. The motor assembly includes a motor driver, an automatic transfer switch, a capacitive load, and an alternating current motor. In the case that the automatic transfer switch is energized, windings of the alternating current motor are kept connected to the motor driver, and in the case that the automatic transfer switch is deenergized, the windings of the alternating current motor are switched to be connected to the capacitive loads. The motor assembly according to the present disclosure can reduce the falling speed of the stage light fixture in case of the power failure.