Tachometer: how the makes thing easier

Tachometers work on the principle of tacho generators which means the motor generates a voltage according to the velocity of the shafts. The operation can be magnetic, optical-based or simply electromagnetic. Power, accuracy, RPM range, measurements, and display are the specifications of a tachometer. They can be of either analogical or digital. Here we list for you the different digital types.

Differentiation

Based on data inputs, the tachometers are basically of two types: Contact Type and Non-Contact Type. Based on operation techniques, the tachometers are also of two types: Time measurement and Frequency measurement.

Contact Type

The type of tachometer that remains in contact with the rotating shaft is known as Contact Type Tachometer. It is attached to the electric motor or the machine directly. The rotation per minute or RPM can be measured by attaching a magnetic sensor or an optical encoder. They are capable of measuring low-speeds at 0.5 rpm and high speed at 10,000 rpm and also chances for circumference measurement is available.

Non-Contact Type

The type of tachometer having no contact with the rotating shaft is known as Non-contact type Tachometer. An optical disk or a laser is attached that sends output in form of beams that directly reaches the device. This type of tachometer can measure from 1 to 99,999 rpm; the measurement angle is less than 120 degrees, and the tachometer has a five-digit LCD display. Unless the Contact ones these are more durable, reliable and accurate in measurements.

Time Measurements

This type of tachometer calculates the speed by measuring the time period between the incoming pulses. The calculation is independent of the speed of measuring and also the device is more accurate during low-speed calculations.

Frequency Measurements

This type of tachometer calculates speed by measuring frequencies of incoming pulses. It is designed by using a red LED and speed revolution I dependent on the rotation shaft. This device is more accurate during high-speed calculations. These tachometers are of low-cost and high-efficiency, which is in between 1Hz-12 KHz.

Tachometer Generators

It is basically an electrical machine that is used to convert shaft values and rotating speeds into an electric signal. The principle of working of the generator is that the EMF generated is proportional to the angular velocity of the rotor. They are of both AC and DC types and are used as sensors in automobiles and computers as micro electrical machinery.

Electronic Tachometers

Such tachometers are designed only with electronic equipment and are used to measure the speed of engines or any other moving objects according to revolutions per minute. They are mostly used in dashboards of cars to flash the speed details. They are easily visible, low weight and also give accurate readings in any conditions.

The various parts if said in chronological order would be Optical sensing, Magnetic sensing, Signal Conditioning, Microcontrollers, memory and display units.

Nehmat Sandhu is the Contant Writer for Countronics. Countronics is the manufacturer and supplier of Scientific instruments like pH Meter and Controller, Humidity Meter and Controller, Data logger, Digital Counter and timer etc.