Basic knowledge - Non-electronic products

Mechanical and electrical systems can be used as an alternative to electronics for a range of applications. They use proven technology and widely available components to provide robust and reliable solutions.

The key mechanisms in these systems are:

  • Tachometer – the instrument that measures the rotational speed, usually through direct connection
  • Indicator – the instrument that displays the required parameters, usually using a dial with rotating pointer. For mechanical systems, the tachometer and indicator are frequently the same unit

These are used for example where there is either no local power supply, or continuity of power is uncertain, and offer several options to measure rotational speed as well as the consequences such as linear speed, distance, flow, etc. Additionally they don’t require specialist electronics knowledge for installation or minor repairs.

The proven technical principles used with mechanical and electrical instruments not only give a long service life, but can also provide security against the technological advances that often render electronic components and systems obsolete in a relatively short time, making repairs/replacement a simple process.

In some situations there are clear benefits in using a pointer to indicate outputs. The pointer rotation provides an easily identified measure as it is more intuitive than a numerical display, and any system problems or vibration is often visible as the pointer will ‘wobble’.

RHEINTACHO have been making these systems for many years and can offer support to help provide a solution, and even reverse engineer systems to replace obsolete instruments where the original manufacturer has ceased production.

Mechanical tachometers / indicators

RHEINTACHO mechanical tachometers simultaneously measure the speed of rotating objects and display the required parameters on a dial. As they are connected directly to the point of movement they need no additional power supply and are often used in hazardous areas.

Also referred to as eddy current tachometers, they are exceptionally robust and ideally suited for use in harsh, industrial environments. We also take account of operational aspects, using clear displays with a well-structured, high-contrast and clear figures making them easy to read. Dials can be marked with identifications such as red lines, warning zones or direction of movement. In some cases it is also possible to incorporate counters to record additional information.

We offer an extensive range of options, and whilst each instrument is produced and calibrated to individual specification, there are standard case sizes and configurations. To help us to understand your requirements there is also a download form for specifications.

Operating principles
Mechanical tachometers use the eddy current principle. The indicator is directly connected to the point of movement, either with a fixed shaft/connector or through a flexible cable drive. The movement is transferred to the indicator shaft and this rotation creates a magnetic field which causes the pointer to deflect. As the speed of rotation increases, so does the strength of the magnetic field and therefore the deflection. The instrument is calibrated to the application and the scale range and units specified by the customer.

Mechanical tachometers are regularly used in many different applications where the display needs to be close to and directly connected to the point of measurement. Typical examples include process monitoring, test rigs and control centres. In turn, these are employed in mining (drilling equipment), on ships (engines and gears), in steel mills and chemical plants (mixing equipment). Further applications include large engines and turbines where they both measure speed as well as providing a clear indication that the equipment is operating.