When we buy an infrared camera, we often notice a parameter, which is the minimum illumination. So, what is the concept of minimum illumination? The minimum illuminance of the infrared camera is the brightness value of the monitored scene when the brightness of the monitored scene is low to a certain extent and the video signal level output by the camera is lower than a certain value. There are some people in the market with the minimum illumination of the infrared camera, or even the default is 0, you can imagine, how funny it is. We know that CCD is a photosensitive component. How can it be imaged without light? Therefore, the minimum illuminance can only be close to the value of 0, but it must not be equal to 0. We pay attention to this when purchasing an infrared camera. When the minimum illumination of the selected infrared camera is higher than the requirement of the infrared lamp, the effective illumination distance of the infrared lamp will be affected. Users should be reminded that there are two kinds of abnormal conditions in the minimum illumination of the technical performance of some cameras on the market. One is that the minimum illumination of the camera manufacturer is the so-called target illumination, that is, the illumination on the CCD image sensor. It is about 10 times lower than the illumination of the scene; the other is the technical indicator that the individual camera manufacturer or seller falsely reports the minimum illumination. At present, the actual minimum illumination of a black and white camera on the market (some minimum illumination is 0.01 to 0.02Lx) is only 0.1 to 0.2Lx. If the infrared lamp used requires the minimum illumination of the infrared camera to be 0.02Lx, it will inevitably affect The effective illumination distance of the infrared light. For cameras with a minimum illumination of 0.02 Lux, the price may be at least double that of a camera with a minimum illumination of 0.1 to 0.2 Lux.
Roller bearing, one of the two members of the class of rolling, or so-called antifriction, bearings (the other member of the class is the Ball Bearing). Like a ball bearing, a roller bearing has two grooved tracks, or races, but the balls are replaced by rollers. The rollers may be cylinders or truncated cones. Only radial loads (i.e., loads perpendicular to the axis of rotation) can be carried when the rollers are cylindrical, but with conical rollers both radial and thrust, or axial, loads (i.e., ones parallel to the axis of rotation) can be carried. A needle bearing has cylindrical rollers that are relatively slender and completely fill the space between the races; in many cases the inner race is dispensed with. Because there is line contact between a roller and the races, while in a ball bearing there is point contact, in a given space a roller bearing can carry a greater radial load than a ball bearing.
Roller bearings are used in all main shaft and auxiliary drive shaft applications to support pure radial load, and allow for axial shaft elongation due to temperature changes with no additional load effect on the bearing. They are usually located at the ends of the turbine and compressor shafts and are often mounted in a housing, but separated from it by a layer of pressurized oil known as a squeeze film damper. Roller Bearing,Self-Aligning Roller Bearing,Double Row Roller Bearing,Neddle Roller Bearing Shijiazhuang Longshu Mechanical & Electrical Equipment Trading Co., Ltd. , https://www.lsjgbearing.com
In many cases, instead of having a separate inner race for roller bearings, the [inner race" is an integral part of the shaft or stub shaft. This reduces complexity, weight, and build-up of concentricity tolerances. Overall, this is cost effective, but the cost of replacement or repair is likely to be higher than for separate inner races.
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