High and low temperature test is the abbreviation of high temperature test and low temperature test. The purpose of the test is to evaluate the impact of high and low temperature conditions on the performance of equipment during storage and operation.

Test equipment:

      The high temperature test is generally to place the product in a constant temperature box or a constant temperature room for testing. The temperature of the medium is measured at different positions with a thermometer, and the arithmetic average is taken. However, the temperature in the box is required to be as uniform as possible, and the product is heated by the flow of hot air, and the test sample should not be close to the heat source. In order to reduce the influence of radiation, the wall temperature of the test chamber should not be higher than 3% of the ambient temperature.

      The low temperature test is generally carried out in a low temperature box (chamber), and its temperature is generally obtained by artificial refrigeration. In the effective working space of the low temperature box, forced air circulation is used to maintain the uniformity of low temperature conditions.

Test parameters:

       According to the standards GB/T 2423.1-2008 & IEC60068-2-1:2007, GB/T 2423.2-2008 & IEC60068-2-2:2007, the priority values of different temperature levels are specified according to different regions and usage occasions.

       Low temperature environment temperature: one 65℃, one 55℃, one 45℃, one 40℃, one 30℃, one 25℃, one 15℃, one 10℃, one 5℃, 0℃, +5℃.

       High temperature environment temperature:

+200℃, +175℃, +155℃, +125℃, +100℃, +85℃, +70℃, +65℃, +60℃, +55℃, +50℃, +45℃, +40 ℃, +35℃, +30℃.

       The allowable range of temperature deviation is ±2℃. After the temperature of the test sample is stable, the duration of the high and low temperature test is selected from the following data as needed: 2H, 16H, 72H, 95H, etc.

The basic requirements that the product should meet after the high and low temperature test:

        The quality of the product after the high and low temperature test is generally tested according to the product technical conditions or the requirements specified in the technical agreement. For example, the impact of high temperature environment on the performance of motor products is manifested in the increase in the resistance of conductive materials, resulting in changes in current, and for motors with accuracy requirements, it will also affect accuracy. Therefore, after the high temperature test, the insulation resistance should be measured in the test box, and its value should not be less than 5 MΩ. At the same time, other properties of the motor should be tested. Under normal circumstances, if the product can meet the following basic requirements after temperature test, it is considered that the product meets the high and low temperature requirements.

      1) The surface of the product has no defects such as damage or deformation. If it is a coated surface, there should be no peeling, blistering or discoloration of the coating.

      2) For plastic parts, there are no cracks, blisters and deformation on the surface.

      3) Rubber products are free from aging, bonding, softening and cracking.

      4) There is no flow phenomenon in the welding part of the product.

      5) Product performance data and structural functions meet the requirements of technical specifications, and there should be no other defects that hinder the normal operation of the product.

Introduction to Ward Laboratory: Equipped with walk-in high and low temperature test box, 1m³ constant temperature and humidity test box, 0.8m³ high temperature test box, three comprehensive constant temperature and humidity test boxes, according to customer needs, choose different sizes of cabinets in order to save testing Costs and test scheduling at any time.