What is the No. 648 relay in Volkswagen Lavida?
1 Answers
Volkswagen Lavida's No. 648 relay is the main relay, whose primary function is to control instrument power supply. The relays used in automobiles switch high load power and feature high impact and vibration resistance. Automotive power systems mostly use 12V, with coil voltages generally designed for 12V. Since they are powered by batteries, the voltage is unstable. Under harsh environmental conditions, the pull-in voltage V≤60%VH (rated operating voltage); the coil overvoltage can reach up to 1.5VH, and the coil power consumption is relatively large, typically 1.6~2W. Below is additional information: 1. Composition: Automotive relays consist of a magnetic circuit system, contact system, and reset mechanism. The magnetic circuit system includes components such as the iron core, yoke, armature, and coil. The contact system comprises parts like static reed, moving reed, and contact base. The reset mechanism consists of reset reeds or tension springs. 2. Contact resistance: The contact resistance present between the relay contacts in automotive relays mainly consists of constriction resistance and surface film resistance. The contact resistance is related to factors such as the contact form, material properties, and surface processing. Therefore, to reduce the contact resistance of relay contacts, under a certain contact pressure, improvements can be made by optimizing the contact state and enhancing the contact materials.
