Abstract: This paper describes the design, application, and principle of short-time reciprocating control technology using transistor time relays in our factory, as well as the advantages and disadvantages of the new electrical control system and the old system. The future application of short-time reciprocating control technology using transistor time relays is also discussed. Keywords: Transistor time relay, electrical control system, principle 1. Introduction During my work in the forging workshop of our factory, I found that the automatic feeding mechanism used in the forging workshop was quite cumbersome, especially the electrical part. Not only was the structure complex, but it was also old and in disrepair, lacking even the original circuit diagram. This caused many inconveniences to the work. To solve this problem, I worked with Comrade Wei Fengxiang to jointly research an electrical system to replace the original electrical part, and we succeeded. 2. Principle and Problems of the Original Electrical System 2.1 Principle of the Original Electrical System The automatic feeding mechanism used in our factory's forging workshop uses radio components for short-time control. A small intermediate relay controls the electromagnet to engage, driving the pneumatic valve to achieve automatic feeding. In the electric section, the circuit first undergoes transformation and rectification, followed by amplification via diodes and transistors, frequency adjustment, and crystal oscillator operation, all to control a small intermediate relay. The power supply connects to the electromagnet coil via the normally open contacts of the small intermediate relay, achieving the control purpose. This electrical system was independently developed by our factory in the 1970s, utilizing the small size, low cost, and low technical content of radio components, meeting the standards for use at the time. However, with continuous technological development and advancements, this technology has gradually been replaced and can no longer meet current production requirements. Therefore, Comrade Wei Fengxiang and I researched and improved the system, hoping to replace the old system with a new electrical control system, contributing to the technological innovation of the workshop. 2.2 Problems with the Original Electrical System The original electrical system had not been improved since its development. Although still in use, it was plagued with problems, and its shortcomings gradually became apparent: Due to its early development date, the original technical data was unavailable; circuit diagrams, overhaul records, and component models were not recorded, causing significant difficulties for maintenance. Furthermore, many of the electrical components used at that time are no longer manufactured, making replacement difficult. Due to prolonged use, most components have exceeded their lifespan, resulting in performance degradation and numerous hidden problems. The equipment operates intermittently, and malfunctions cannot be immediately repaired, severely disrupting operations. The old electrical system uses small intermediate relays to control the electromagnet coils; however, these relays have poor voltage and current withstand capabilities, and frequent operation (7-15 times per minute) often burns out the contacts. Furthermore, the small intermediate relays are soldered onto the circuit board, making replacement inconvenient. Therefore, we believe that a technical upgrade to the electrical system of the automatic feeding mechanism is imperative. Initially, we considered using ordinary time relays for control. However, in practice, we found that while air-type time relays have a large delay range and simple structure, their accuracy is low. They are also bulky, and the accompanying intermediate relays, buttons, and switches are also large, hindering installation and use. Later, we considered using electronic time relays, specifically transistor time relays. Source: www.tede.cn 3. Working Principle and Characteristics of Transistor Time Relays 3.1 Working Principle of Transistor Time Relays A transistor time relay consists of five parts: a regulated power supply, a voltage divider, a delay circuit, a trigger, and an actuator (relay). After the power is turned on, the R-C delay circuit, composed of a potentiometer and a tantalum capacitor, immediately charges. After a delay period, the voltage of the tantalum capacitor C in the delay circuit is slightly higher than the threshold potential of the trigger, which triggers the electromagnetic relay, thus connecting or disconnecting the external circuit to achieve the timing action of the controlled circuit. 3.2 Main Technical Data of Transistor Time Relays Power Supply Voltage: AC (220V) ±10%, Frequency 50Hz; Relative Humidity: <85%; Ambient Temperature: -30℃～+40℃; Error ≤±3% (including repeatability error, voltage error, and temperature error); Delay Specification: 60 seconds; Minimum <4 seconds, Maximum 60～70 seconds. 3.3 Characteristics of Transistor Time Relays Transistor time relays differ from older time relays mainly in the following aspects: Small size, light weight, and easy installation. Fully enclosed casing, safe and clean, suitable for the workshop environment. Base-mounted installation, easy replacement. Knob adjustment, convenient and quick. After repeated experiments and overcoming various difficulties, we made full use of our factory's existing equipment and accessories, working overtime and after hours without affecting normal production, and finally succeeded in the experiment. With the cooperation of workshop leaders, it was installed on production equipment, and operators were monitored during use to promptly identify and solve problems, continuously improving until the operators were satisfied. 4. Principle of Short-Time Reciprocating Control Using Transistor Time Relays 4.1 Reasons for Using Transistor Time Relays Transistor time delay relays are important components in automation devices, capable of connecting or disconnecting a device according to a predetermined time. They have advantages such as small size, light weight, high precision, and long lifespan. They are widely used in automatic control systems in metallurgy, machinery, power, chemical, light industry, and petroleum sectors. We use two transistor time relays to complete all actions. Not only does it save a significant amount of control components and reduce size, but it also fully utilizes the convenient replacement features of the transistor time relay's base-mounted design, reducing maintenance time and earning unanimous praise from operators. By using two transistor time relays to adjust the time, it overcomes the limitation of the original electrical system, which could only adjust the pushing time and not the return time. Equipment stability is greatly improved. Utilizing this feature, we have gained a new understanding of the technology of short-time reciprocating control using transistor time relays, and we are very optimistic about its application prospects in our factory and future work. Source: Power Transmission and Distribution Equipment Network 4.2 Electrical Schematic Diagram of Short-Time Reciprocating Control Using Transistor Time Relays: Meaning of Components in the Diagram: QS————————————————-Power Switch; JS1, JS2——————————-Transistor Time Relays; Dct————————————————Electromagnetic Coil; 4.3 Electrical Principle: When the power switch QS is closed, current flows through the delayed-open contact of transistor time relay JS2 (delayed opening when the operating device is energized), energizing the coil of transistor time relay JS1. When the JS1 transistor time relay coil is energized, its delayed-closing contact (which closes after a delay when the operating device is attracted) closes. This energizes the JS2 transistor time relay coil, and simultaneously, its normally open contact closes, energizing the electromagnet coil and disconnecting it to drive the pneumatic valve, completing the pushing action. After the JS2 transistor time relay coil is energized, its delayed-opening contact opens after a delay, de-energizing the JS1 transistor time relay coil. After the JS1 transistor time relay coil is de-energized, its delayed-closing contact immediately opens, de-energizing the JS2 transistor time relay coil. Simultaneously, its normally open contact opens. The electromagnet coil is de-energized, the pneumatic valve resets under spring pressure, and the pusher rod retracts, completing all actions. After the JS2 transistor time relay coil is de-energized, its delayed-opening contact resets and closes, energizing the JS1 transistor time relay coil. This puts the entire electrical system into a cyclic state. The timing control for material pushing and retraction is achieved through the adjustment knobs of two transistor time relays, JS1 and JS2. Adjusting the knob of transistor time relay JS1 controls the material pushing waiting time. Adjusting the knob of transistor time relay JS2 controls the dwell time of the pusher rod after pushing the material. Because the timing adjustment of the transistor time relays is fully enclosed, circulating only within their internal loops, the influence of the external environment is reduced. This makes the timing adjustment more flexible, safe, and reliable. It brings convenience to the operator and reduces the failure rate; from this perspective, our innovation is successful. 5. Characteristics of the New Electrical Control System The new electrical control system, replacing the old system, has the following characteristics: The electrical principle of the new electrical control system is simpler than that of the old system, allowing anyone to quickly master its use without further training. The new electrical control system is small in size and lightweight, facilitating installation and use. The new electrical control system uses only two transistor time relays, resulting in fewer electrical components, and these are universal parts, making replacement and maintenance convenient. The transistor time relays are internally electronically integrated, offering high stability and the ability to operate frequently (alternating 30 times per minute). The new electrical control system not only meets current work needs but can also perform tasks in other areas, such as automatic material handling in the unloading workshop and automatic clamping in the machining workshop. Source: http://www.tede.cn 6. Conclusion Through repeated practice and demonstration, we believe that the technology of using transistor time relays for short-time reciprocating control is feasible and has been successfully implemented. In future work, we will work even harder, utilizing our knowledge to continuously improve and enhance our technology, and cooperate with other colleagues to jointly improve the outdated technical level of our factory. We are full of confidence in future technological innovations.