June 7, 2023
The term “tachometer” came from two Greek words, namely: tachos which means speed; and metron which means “measure.” Hence, etymologically, the word “tachometer” means “measure of speed” or “speed measurement.” Well, the etymological meaning of tachometer tells something about what it does, for a tachometer basically measures the rotational speed of a disk or shaft. It shows this measurement in revolutions per minute (RPM) on an analogue dial, although digital tachometers are increasingly becoming popular and common. The tachometer is also referred to as revolution-counter, rev-counter, RPM gauge, and tach.
The tachometer is specifically a device that indicates the angular speed or rotary speed of any rotating shaft. However, the term sometimes only refers to the electrical and mechanical instruments that show the instantaneous values of speed in RPM but do not indicate the average values of speed for a given interval.
How To Use Tachometer on Small Engine?
Since the tachometers used on aircraft, cars, and other vehicles only indicate the rate of the engine’s crankshaft’s rotation, but they can surely show the safe range of rotational speeds. With the data a tachometer provides, a driver can readily select the specific gear and throttle settings for any given driving experience and condition. Thus, the tachometer can prompt a driver to slow down when he/she is continuously moving at high speed, for prolonged rate use of crankshaft at high speed can surely cause problems like overheating, inadequate lubrication, damage to sub-parts of the engine. The onset of these damages can eventually lead to the partial or total breakdown of the engine.
Drivers whose cars are with manual transmissions, for example, would surely benefit from the data provided by the tachometer. The analogue tachometer, for example, would prompt a red signal on the gauge area indicating that the driver is operating at unsafe speed. On the other hand, in cars with automatic transmissions, the presence of the red zone is already superfluous because automatic vehicles are already equipped with a revolution limiter that electronically prompts or limits the engine speed when the car is speeding beyond its engine limitation. Thus, you would not find this red line in cars that are equipped with this revolution limiter feature. Moreover, you would also not find this redline in machines with diesel engines that are equipped with mechanical injector systems that have an integral governor, for this integral governor is designed to prevent the engine from over-speeding.
Most Recommended Tachometers for Small Engine
1) Runleader Digital LED Engine Hour Meter
If you are looking for a multifunctional meter, you can check out the Runleader Hour Meter. This tachometer can function as a TACH/Hour meter, Temp meter gauge, hour meter, and tachometer. First, it can gauge engine temperature, TOT hours, maintenance service timer, and many more.
Second, as a temp meter gauge, you can use its temp sensor to get the engine’s temperature in real-time. You can likewise program it to give you an over-temperature alert. Moreover, you can view the maximum temp value and reset it. As an hour meter, you can use the TOT hours to track the working hours of the engine. Nevertheless, you can’t reset the TOT hours.
As a tachometer, this equipment records the RPM value in real-time. It also enables you to adjust the engine idle time. Moreover, you can program the patterns of engine firing to keep more accurate the RPM value.
You can quickly install its LED display, and a 12V external power supply powers it. It also retains data when you shut it down, and it comes with a two-year warranty.
2) AIMILAR Digital Tach Hour Meter Tachometer
AIMILAR Digital Tach Hour Meter is a popular product that many consumers use. It is popular because it is affordable and of quality. It would not burn your wallet when buying this tach/hour meter. It is easy to install and operate. You only need to activate it when you use it for the first time by pressing S1+S2. It will show 00000-99999. Then, it shuts off. In doing so, you successfully activate it.
This unit will function on two-stroke single, two cylinders, two-stroke, four-stroke single-cylinder, four-stroke two-cylinder, and four-stroke four-cylinder engines. It also features a power-saving mode.
Its LCD will automatically shut off if you are not operating it for sixty seconds. It also automatically starts when you start the engine. Moreover, you need to set the firing pattern of the spark plug correctly. Its factory default setup is also once every revolution. (1P1R).
The AIMILAR Meter features a green backlight. It also comes with a sizeable seven-segment LCD with a CR2450 Internal battery.
3) Runleader Hour Meter Tachometer
Runleader Hour Meter Tachometer is another excellent option that is easy to program and suits different applications. It is easy to install and works well. Moreover, it comes with features like Tachometer (RPM), Service Timers (SVC&SVC2), Hour Meter, Resettable Job Timer (JOB). The data is easy to view, and you can manage with ease the health of your engine using this device.
You can program the maintenance interval service timer. It can also remind you about the countdown tracking service. Once the SVC time is reached, you will see a warning icon on its LCD, and its backlight will turn red.
Its JOB timer will also allow you to measure a specific work job like change oil and even the job time for air filter replacement. Besides, you can reset the value and view the SVC and JOB readings by clicking on the related buttons.
4) Searon Store’s Small Engine Tachometer Hour Meter
If you need a tachometer to track your engine’s RPMs as well as its running time, you should consider the Searon Store’s Small Engine Tachometer. A CR2032 battery powers it, so you don’t need to connect it to any external power. With the help of its 5-ft insulated wire, the connection of this Tach/hour meter is made possible. You simply need to wrap the wire five times to the spark plug. The engine’s spark activates this Tach/Hour Meter.
The common usage of this Tach/hour meter includes RC toys, (2/4 stroke) engines, marine engines, motorcycles, tractors, chain saws, marine engines, (gas-powered) tools, and lawnmowers. This (Tach/hour) meter records the operation’s total run time, which is non-resettable. It can also registers job time which you can reset. Besides, you can program its SVC timer from 0 to 200 hours.
5) Foundown’s Engine Hour Meter
If you want something with a powerful timing system as well as an RPM measuring system, you should check the Foundown’s Engine Hour Meter. Its timing system includes accumulating total running time and recording JOB time. It also has a maintenance timer that you can set freely from 0 to 200 hours SVC. It also has an RPM measuring system that includes current engine RPM measurement and allows you to view MAX RPM’s engines.
It also sets an Overspeed Warning function, and you can also set its refresh rate. Moreover, it comes with a unique design that makes it easy to install, with a replaceable CR2032 battery. It can store data automatically after replacing its battery, and comes with a green backlight LCD.
It also comes with a waterproof Rate IP65. Besides, it is the perfect rev counter for ATV, motorcycles, PWC, scooters, chainsaws, and cleaners.
Purposes of Using Tachometers on Small Engines, Tractors, Trucks & Other Vehicles
Trucks and tractors are usually equipped with tachometers that have other markings such as that of a green arc that indicates the range of speed wherein the engine can produce maximum torque. Operators of the abovementioned vehicles would surely benefit from this green arc feature of the tachometer. Some tractors that are equipped with a power take-off system are also fitted with tachometers that indicate the necessary engine speed for rotating the PTO. It basically indicates the standardized speed required for most PTO-driven equipment.
Regulations vary from country to country with regards to the requirements for a tachometer. Many countries, for example, require tractors to be fitted with a speedometer. Since it would be superfluous to have another dial that indicates speed, the tachometers are usually fitted with a second scale that indicates the unit of speed, and this second scale is fairly sufficient for practical use on the road. On the other hand, tractors that have multiple gears are usually equipped with multiple speed scales. For aircraft tachometers, however, a green arc is generally fitted into the tachometers that indicates the standard cruising speed range of the aircraft’s engine.
Different Types of Tachometers That You Can Use On Small Engine
It has been mentioned above that there are analog tachometers and digital tachometers. However, there are also contact and non-contact tachometers and time and frequency-measuring tachometers. Here is an in-depth description of these different types of tachometers:
1) Analog Tachometers
These tachometers feature a dial-type interface and a needle. They, however, does not come with storage for readings and are incapable of computing the average and deviation in RPM. The analog tachometers make use of a mechanism that converts speed into voltage. The voltage is eventually displayed on the tachometer.
2) Digital Tachometers
The digital tachometers feature either a LED readout or an LCD readout with concomitant memory for storage. These tachometers can do statistical operations and can provide precise monitoring and measurement of whatever type of time-based quantities. There is increasing use of digital tachometers nowadays, and they are becoming fairly common for they are easy to read with their numerical readings.
3) Contact and Non-contact Tachometers
The contact type of tachometers features a direct contact with the rotating shaft. They are equipped with a magnetic sensor or an optical encoder. On the other hand, the non-contact type is suitable for mobile applications. It also makes use of an optical or laser disk. These two types of tachometers are basically ideal for use if you want to have precise measurements and they are useful for data acquisition purposes.
4) Time and Frequency Measuring Tachometers
These tachometers relied heavily on measurement methods. The time-measuring tachometers, for example, readily calculate the speed by merely measuring the temporal interval or lapse between two incoming impulses. These tachometers are ideal for use in measuring low speed. On the other hand, the frequency-measuring tachometers calculate the speed by merely measuring the incoming pulses’ frequency. Lastly, the frequency-measuring device is suitable for measuring high-speed rate.