Dryer Motor Control Circuit Using Thyristor and Mechanical Switch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional control circuits for single-phase AC motors in dryers have complex structures, high costs, and significant electrical losses due to high power consumption and current in switching and drive circuits.
Innovation Solution
A control circuit for a single-phase AC motor that includes a bidirectional triode thyristor, a mechanical switch, and interlocked drive circuits, utilizing a hysteresis control circuit and electromagnet coil to simplify the structure and reduce electrical losses by controlling the mechanical switch's operation, thereby minimizing heat and electric losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional electronic power switches (silicon-controlled rectifiers) are used in switching and drive circuits, then control convenience is improved, but circuit complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates complex electronic power switching components (silicon-controlled rectifiers) from the circuit, replacing them with simpler electronic switches that maintain control convenience while reducing circuit complexity and cost
Solution Approach 2:
The patent replaces expensive electronic power switches with more economical switching components that achieve the same functional purpose, reducing overall circuit cost while maintaining operational effectiveness
2Power
If electronic power switches are powered on with high electrical heating wire power, then heating capability is improved, but current and heat value of the switch increase causing greater electric loss
Solution Approach 1:
The patent implements periodic switching control where the electronic switch operates in pulsed cycles rather than continuously, allowing the heating wire to receive adequate power during active periods while the switch remains off during idle periods, thereby reducing overall current through the switch and minimizing electric loss
Solution Approach 2:
The patent employs dynamic control of the switching timing and duration, adjusting the switch-on periods to coincide with when heating power is needed while keeping the switch off during periods of lower demand, optimizing both heating performance and energy efficiency
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 results in a simple, cost-effective control circuit with reduced electrical losses and improved motor control efficiency, allowing for accurate switching and efficient operation of the dryer motor.
Implementation Method 1
a bidirectional triode thyristor, a mechanical switch K... The bidirectional triode thyristor is serially connected to a starting winding and a starting capacitor of the motor
Implementation Method 2
the second drive circuit comprises an electromagnet coil L, the electromagnet coil L switches on the mechanical switch K as the second drive circuit is conducting
Implementation Method 3
the voltage comparing circuit is a hysteresis control circuit... the hysteresis control circuit is capable of switching off an operating loop of the motor of the dryer at a current higher than that of the main winding
Data Source
AI summary
A control circuit for a single-phase AC motor of a dryer, including at least an electronic starting circuit including at least a starting control unit, a first drive circuit, and a bidirectional triode thyristor, a second drive circuit, and a mechanical switch K. The bidirectional triode thyristor is serially connected to a starting winding and a starting capacitor of the motor, and connected to an AC input. The starting control unit is connected to a control end of the bidirectional triode thyristor via the first drive circuit. The mechanical switch K is serially connected to an electrical heating wire, and is connected to the AC input. The starting control unit is connected to a control end of the mechanical switch K via the second drive circuit. The first drive circuit and the second drive circuit are interlocked with each other.