Structural characteristics of low-voltage switchgear
Sep 10, 2020
Low-voltage switchgear is suitable for power plant, petroleum, chemical, metallurgical, textile, high-rise buildings and other industries, for power transmission, distribution and power conversion. So what are its structural characteristics?
1. Fixed type:
It can be satisfied that the electrical components are reliably fixed in the determined position in the cabinet. The shape of the cabinet is generally cubic, such as screen type, box type, etc., and there are also prisms such as desktop. This kind of cabinet has a single row and also has an arrangement.
In order to ensure the shape and size of the cabinet, the components are often combined step by step. Generally, two pieces or left and right sides are formed first, and then the cabinet is formed, or the shape requirements are met first, and then the internal supports of the cabinet are connected in sequence. The length of the parts that make up each edge of the cabinet must be correct (the tolerance is negative) to ensure the geometric dimensions of all aspects, thereby ensuring the overall shape requirements. For the two sides of the cabinet, due to the need for arrangement, there should be no bulge in the middle.
In addition, from the perspective of installation, there should be no sinking of the bottom surface. In the arrangement and installation, the foundation leveling is a prerequisite, but the dryness and the cabinet itself have certain errors. In the arrangement, the lateral difference should be offset as much as possible, and the difference should not be accumulated, because the accumulation of the difference will cause the cabinet to deform , It affects the bus connection and causes the component installation to be out of place, stress concentration, and even affects the life of electrical appliances. Therefore, it is advisable to use the highest point of the foundation as the installation reference point when arranging, and then gradually expand the arrangement. Under the condition that the bottom dryness is ideal and predictable, the arrangement can also be expanded from the middle to both sides to make the accumulated difference evenly cloth.
In order to facilitate adjustment and offset the accumulation of tolerances, the cabinet width tolerances are all negative. After the combination of each component of the cabinet body is completed, it should be reshaped as necessary to meet the requirements of the shape and size of each part. The use of tooling and fixtures should be fully considered when manufacturing cabinets with a finalized shape or a large batch. To ensure the correctness and unity of the structure, the base surface of the fixture should be taken from the bottom surface. The positioning blocks in the fixture are arranged to facilitate the removal of work. The outer door of the cabinet is easily affected by transportation and installation, so it is generally installed Make unified adjustments at the time.
2. Withdrawal type:
The draw-out type is composed of a fixed cabinet and a movable device part equipped with main electrical components such as switches. The movable part should be light and portable when it is moved, and the positioning should be reliable after being moved, and the drawers of the same type and specification can be reliably interchanged and drawn out The processing method of the cabinet in the formula is basically similar to that in the fixed cabinet. However, due to the interchange requirements, the accuracy of the cabinet must be improved, and the relevant parts of the structure must have sufficient adjustments. As for the movable device part, it must be able to be replaced, and the main components must be reliably installed, so it must be higher. With high mechanical strength and high precision, the relevant parts must have sufficient adjustment.
The process characteristics of manufacturing drawer type low voltage cabinet are: (1) The fixed and movable parts must have a unified reference standard; (2) The relevant parts must be adjusted to the best position, and special standard tooling shall be used when adjusting, including the standard cabinet body. And standard drawers; (3) The error of key dimensions cannot be out of tolerance; (4) The interchangeability of drawers of the same type and specification must be reliable.
