A tachometer is a device that measures the speed of rotation of an axis, usually the speed of a motor. It is measured in revolutions per minute (RPM). In antiquity, the first tachometers were based on measuring the centrifugal force. It is not safe, but it is believed that the inventor was a German engineer who used it to measure the speed of the machines about the year 1817. About 30 years later, it began to be used to measure the speed of locomotives.
Currently, it is usually installed on board of certain road vehicles, to indicate and record automatically, the data related to the kilometers traveled and the speed of the vehicles, as well as the times of activity and rest of their drivers. They can be analog or digital. Tachometers measure both the number of revolutions (turns of an axis) and the speed with which the axis rotates and, by extension, the speed with which a motor rotates.
They measure the revolutions per minute. To make their expression easier, they express this unit of the frequency multiplied by 1,000. Therefore, the indicator can express numbers from 1 to 8 for example. If the needle of the tachometer shows a 4, it means that the engine we are analyzing rotates at a speed of 4,000 revolutions per minute. This engine would complete 4,000 laps in a minute. Initially, the tachometers were mechanical and measured by the centrifugal force. Currently, most are digital and so are much more accurate.
We often find tachometers in cars, although not all models include them. In some cars, the device is part of the instrument panel and tells the driver how fast the engine crankshaft turns. Thus, the driver can see what speed of rotation can potentially be dangerous to the engine and thus adapt the gear. Through the tachometer of a car, it is possible to know the effort that the engine is making. It is not an essential instrument for driving and perhaps less important than others, such as the speedometer, but even so, it can be a very useful tool.
We also find portable hand tachometers. The hand tachometer can measure in two ways, optically without contact, or mechanically using adapters. In the optical measurement, a beam of light is focused on the object to be measured, which bounces off a reflective band stuck on the object to be measured, indicating the frequency of rotation. The result appears on the 5-digit LCD screen. The distance between the digital tachometer and the object to be measured can reach up to 600 mm. The mechanical measurement of the revolution is made with a tip adapter that is placed on the axis of the moving part. For the measurement of speed or distance, a wheel adapter is placed on the tip. A digital adapter allows you to measure distances and speeds of wires, wires or fibers (glass) with the digital tachometer.
The digital tachometer is very useful when installing machines and installations, as well as for maintenance, checking or work in the development laboratory. It can measure revolutions of motors, turbines, pumps, agitators, centrifuges or transport facilities, as well as lengths of wires, sheets or bands.
Tachometers usually have the following parts:
– Reflective brand
– Signal indicator
– Measure button for laser
– Selection button
– Function switch
– Outdoor antenna
– Antenna under construction
– Variable resistor