RPM Meter for Motors and Rotating Components

Frequently Asked Questions About Speed Measurement

Rotational speed can be measured electronically via the vehicle or a machine control system, or independently, directly on the rotating component. The most appropriate method depends on accessibility, the speed range, the surface, and the diagnostic task. The MT 6000 enables both non-contact and mechanical measurements and can also measure linear velocity.

• What does a tachometer measure?

  A tachometer measures how many times a shaft, pulley, or other rotating component rotates within a given period of time.

  In the automotive and machinery sectors, rotational speed is typically expressed in:

  revolutions per minute – rpm.

• When is external speed measurement useful?

  Independent speed measurement can be useful, for example, when:

  • no electronic speed signal is available,
  • a displayed speed value needs to be verified,
  • work is being performed on engines or machines without vehicle diagnostics,
  • the speed of a separate shaft or other rotating component needs to be determined,
  • a mechanical or optical comparative measurement is required.
• Can a tachometer measure engine speed?

  Yes, provided there is a suitable and safe measurement point.
  
  The MT 6000 can measure RPM either noncontact or mechanically. As a result, it does not rely on an electronic signal from the engine control unit.

• What is MT 6000?

  The MT 6000 is a digital precision tachometer for:

  • non-contact speed measurement,
  • mechanical contact speed measurement,
  • linear velocity measurement.

  The device also features automatic range switching and an automatic data logger.

• What speed can the MT 6000 measure without contact?

  For non-contact measurement, Leitenberger specifies a measurement range of:

  5 to 99,999 rpm.

  This means the device covers a very wide speed range.

• What is the maximum rotational speed that the MT 6000 can measure during contact measurement?

  For mechanical contact measurement, the specified range is:

  5 to 19,999 rpm.

  The measurement range thus differs significantly from that of noncontact measurement.

• Why is the measurement range smaller for contact measurements?

  In contact measurement, motion is mechanically transmitted to the measuring device.

  As a result, the following factors, among others, affect the measuring device:

  • rotational speed,
  • mechanical contact,
  • measuring probe,
  • mounting

  directly on the measuring device.

  Noncontact measurement does not require this mechanical contact and is therefore specified for significantly higher rotational speeds in the MT 6000.

• How does noncontact speed measurement work?

  In non-contact measurement, rotation is detected optically.

  The MT 6000 comes with reflective tape that can be attached to a suitable location on the rotating component. The measuring device then detects the recurring reflection and uses it to determine the rotational speed.

• Why is reflective tape needed?

  The reflective tape creates a clearly recognizable optical reference point on the rotating component.
  
  With each revolution, this mark passes through the device's measurement range again.
  
  The rotational speed can be calculated based on the number of these events per unit of time.

• How much reflective tape is included?

  The package includes 0.60 m of reflective tape. ET 43 is also available as a 60-cm reflective tape replacement part.

• Does the reflective tape have to be applied all the way around?

  No.
  
  For normal speed measurement, the device requires a defined, recurring reference point and does not require a fully reflective surface.
  
  The mark must be positioned so that it can be reliably detected.

• Why should only a unique reflective marker be used?

  If multiple equivalent reflection marks are detected per revolution, the device may register multiple pulses per actual revolution.
  
  As a result, a correspondingly multiple speed value may be displayed.
  
  For simple, direct speed measurement, a clearly defined measurement point should therefore be used.

• Can measurements be taken without reflective tape?

  That depends on whether the existing surface produces a sufficiently distinct optical signal.
  
  For reproducible noncontact measurements, the provided reflective tape is the more reliable solution.

• What is the advantage of non-contact speed measurement?

  The main advantage is that the measuring device does not need to make mechanical contact with the rotating component.

  This is particularly useful in the following cases:

  • high rotational speeds,
  • shafts that are difficult to access mechanically,
  • sensitive components,
  • and applications where rotation should, if possible, not be affected by a measuring contact.
• Is a noncontact measurement automatically safe?

  No.
  
  “Non-contact” simply means that the measuring device does not require mechanical contact with the rotating component.
  
  Rotating components can still pose significant hazards. The measurement point, distance, and operating procedure must therefore be selected so that the measurement can be performed in accordance with applicable safety and manufacturer specifications.

• What is a mechanical contact measurement?

  In contact measurement, a suitable measuring attachment is placed directly against a rotating shaft or measuring surface.

  The rotation is mechanically transmitted to the measuring device, which then determines the rotational speed.

  The MT 6000 is supplied with, among other things, a probing tip and a hollow cone for this purpose.

• What is the probe tip used for?

  The probe tip is used to establish mechanical contact at a suitable rotating measurement point.
  
  The choice of tip or attachment depends on the shape and accessibility of the rotating shaft.

• What is the hollow cone used for?

  The hollow cone offers an alternative contact geometry.
  
  It can be mounted on a suitable shaft or axle shape where a probe tip is not the most practical contact option.
  
  The MT 6000 includes both a probe tip and a hollow cone.

• When is contact measurement more appropriate than optical measurement?

  A contact measurement may be useful if:

  • no suitable optical surface is available,
  • a reflective strip cannot be attached,
  • the shaft has an easily accessible contact point,
  • and a linear velocity is also to be measured.

  However, at high rotational speeds or when access is difficult, noncontact measurement may offer advantages.

• Can the MT 6000 also measure speed?

  Yes.

  In addition to rotational speed, the MT 6000 can measure linear speed using the included impeller.

  The measurement range is:

  0.05 to 1,999.9 m/min.

  Alternatively, the device can display 0.2 to 6,560 feet/min.

• What does m/min mean?

  m/min stands for meters per minute.

  In this case, it is no longer the number of revolutions that is measured, but rather the linear distance that a surface travels in one minute.

• What can linear velocity measurement be used for?

  Linear speed measurement can be useful, for example, in:

  • conveyor belts,
  • rollers,
  • moving belts,
  • machines,
  • test benches

  The MT 6000 thus expands beyond pure rotational speed measurement to include an additional mechanical measurement function.

• How is linear velocity measured?

  To do this, use the impeller included in the package.

  In a suitable application, the impeller is driven by the moving surface. The measuring device then determines the linear velocity based on the impeller's rotation.

  The included impeller is designed for measurements in meters or feet per minute.

• Can the rotational speed be measured at the same time as the wheel is turning?

  The encoder is primarily used to convert rotation into a linear velocity reading.
  
  For direct speed measurement, however, the appropriate optical or mechanical speed measurement methods are used.

• What is the difference between rotational speed and velocity?

  Rotational speed describes how often a component rotates:

  rpm

  Linear speed, on the other hand, describes the distance a surface travels:

  m/min

  For example, a roller may have a specific rotational speed, while its circumferential speed also depends on the roller's diameter.

• Can you automatically calculate speed from the RPM?

  Only if the relevant geometry—such as the diameter of a roller—is also known.
  
  The MT 6000 therefore offers direct linear contact measurement with the impeller for suitable applications.

• What is the display accuracy of the MT 6000?

  Leitenberger specifies the display accuracy as:

  ±0.05% or ±1 digit of the measured value.

  Of course, to ensure a meaningful measurement, the measurement method and measurement point must also be selected correctly.

• What kind of display does the MT 6000 have?

  The device has a five-digit LCD display.

  The digit height is 10.2 mm.

• Why is a five-digit display useful?

  The wide speed range extends to nearly 100,000 rpm.
  
  A five-digit display therefore allows even high speeds to be shown directly without the need for additional conversion.

• What does “automatic range switching” mean?

  The MT 6000 automatically adjusts the measurement range to the measured variable.
  
  This eliminates the need for the user to manually switch between ranges every time the speed changes. Leitenberger explicitly specifies this feature for the MT 6000.

• What does the automatic data logger do?

  The automatic data logger helps ensure that measured values remain available or readable after a measurement.
  
  This is particularly useful when the display cannot be monitored continuously during the actual measurement.

• Does the MT 6000 require a power supply from the vehicle?

  No.

  The tachometer operates independently of the vehicle's electrical system.

  It is powered by four R6 AA batteries, each rated at 1.5 V.

• Does that mean the MT 6000 can also be used on the go?

  Yes.

  Since no connection to the vehicle's electrical system or to shop compressed air is required, the handheld unit can also be used on the go with:

  • vehicles,
  • engines,
  • machines,
  • test benches
• Can MT 6000 be used in gasoline and diesel engines?

  The measurement principle does not depend on the type of fuel.
  
  What matters is that there is a suitable rotating measurement point for optical or mechanical detection.
  
  Therefore, external RPM measurement can be useful for both gasoline and diesel engines.

• Does the MT 6000 need to be connected to the ignition?

  No.

  To measure engine speed, the device does not need to be connected to:

  • ignition wires,
  • the ignition coil,
  • the fuel injection system,
  • or the engine control unit.

  It measures the actual mechanical rotation optically or via contact.

• Does the MT 6000 need to be connected to the OBD interface?

  No.
  
  The MT 6000 is a standalone mechanical-optical measuring device and operates independently of the OBD interface.

• What is the difference between the MT 6000 and a diagnostic device?

  A diagnostic tool can read a RPM value from the engine control unit in a compatible vehicle.
  
  The MT 6000, on the other hand, measures the actual rotation directly on the component being tested.
  
  These are therefore two different measurement methods.

• Why can an independent RPM measurement still be useful despite OBD?

  The value displayed by the control unit is based on:

  • the sensor,
  • signal transmission,
  • the control unit,
  • and available diagnostic data transmission.

  An external measurement records the mechanical rotation independently of these factors.

  This allows it, for example, to serve as a reference measurement or to be used on components for which rotational speed data is not available via OBD at all.

• Does a discrepancy between the OBD RPM and the MT 6000 automatically mean that the RPM sensor is defective?

  No.

  First, the following must be checked, among other things:

  • correct measurement point,
  • correct reflection mark,
  • measurement conditions,
  • correct correlation between the measured wave and the displayed engine speed.

  Only then can it be determined whether there is actually a significant deviation.

• Can the MT 6000 measure the rotational speed of a turbocharger?

  I would not make a blanket recommendation here.

  Turbochargers can reach extremely high rotational speeds, and their rotating components are typically not accessible as suitable external measurement points during operation.

  For this reason, special turbocharger test and diagnostic tools are available for diagnosing turbochargers.

• Can the fan speed be measured?

  In general, rotating components that can be measured noncontact can be detected if:

  • the rotational speed is within the measurement range,
  • a suitable optical reference is available,
  • a safe measurement position is possible.

  When fans are running, particular attention must be paid to maintaining the required safety distance.

• Can the rotational speed of a pulley be measured?

  Provided the surface is safely accessible and suitable, a pulley can generally serve as a potential optical measurement point.
  
  It is crucial that the measured rotational speed actually corresponds to the component being diagnosed.

• Do all of an engine's pulleys rotate at the same speed?

  No.
  
  Due to differences in pulley diameters or gear ratios, auxiliary components can operate at speeds different from that of the crankshaft.
  
  Therefore, a measurement taken at any pulley should not automatically be interpreted as the engine speed.

• Can the MT 6000 be used to measure the slippage in a belt drive?

  By comparing appropriate rotational speeds or velocities—and given knowledge of the gear ratio—additional information can be obtained.
  
  However, a single rotational speed measurement alone does not prove belt slippage.

• Can the rotational speed of an electric motor be measured?

  The optical or mechanical measurement principle is not, in principle, limited to internal combustion engines.
  
  Therefore, if a suitable, accessible shaft is available, the rotational speed of other engines or machines can also be measured.
  
  The applicable safety requirements and permissible rotational speeds must be taken into account.

• Can this be used to measure the rotational speed of an electric vehicle's drive motor?

  Not across the board.
  
  In electric vehicle drivetrains, the rotating high-voltage components are typically located in enclosed and safety-critical assemblies.
  
  These must not be opened or made accessible solely for the purpose of external speed measurement.
  
  The device should only be used at designated and safe external measurement points.

• Can the RPM be measured while driving?

  The MT 6000 is a handheld measuring device designed for suitable stationary testing and measurement applications.
  
  Using it to measure freely rotating components on a moving vehicle would not be a practical or safe application.

• Why does the measurement point need to be easily accessible for contact measurements?

  The measuring device or measuring probe must make mechanical contact with the rotating part.

  An unsuitable, unstable, or hard-to-reach measuring position can:

  • skew the results,
  • cause the measuring probe to slip off,
  • pose a safety risk.

  Therefore, if access is difficult, it is better to check whether noncontact measurement is possible.

• Can the contact measurement affect the rotational speed of the component?

  For small or low-power drives, a mechanical measuring contact can generally place an additional load on the system.
  
  Therefore, you should use only the measuring attachment intended for the device and apply as little contact pressure as necessary.

• What can cause an incorrect optical measurement?

  Possible causes of implausible values include, for example:

  • multiple reflection points per revolution,
  • an unsuitable surface,
  • poor alignment,
  • varying distance,
  • interference reflections,
  • incorrect measurement location.

  If a measurement value is unexpected, the measurement setup should therefore be checked first.

• What does it mean when the rotational speed is twice as high as expected?

  One possible cause could be that the system is detecting two marks per actual revolution.
  
  In that case, the measuring device registers two events per revolution.
  
  Other causes are also possible, which is why the measurement point and the reflective mark should be checked.

• What does a speed value that is half as high mean?

  This can occur, for example, if not every rotation is reliably detected.
  
  Possible causes may include an unsuitable measurement point or unstable optical detection.
  
  Here, too, the measurement setup should be checked first.

• Can the device display speed fluctuations?

  The MT 6000 measures the current speed.
  
  If the speed changes during the measurement, the recorded values will change accordingly.
  
  However, the device is not designed to function as a data logger for comprehensive time-series recording or graphical speed analysis.

• Does the MT 6000 store complete measurement curves?

  No, the current product page does not specify a continuous data logging or charting function.

• Can the MT 6000 generate measurement reports?

  There is no PDF or app-based documentation provided for the MT 6000.
  
  If formal digital documentation is required, the measured value must therefore be documented through the appropriate workshop process.

• What is included with the MT 6000?

  The current package includes:

  • 1 probe tip
  • 1 hollow cone
  • 1 combined wheel for meters/feet per minute
  • 0.60 m reflective tape
  • Carrying case with foam insert.
• Are there replacement parts for the MT 6000?

  Yes.

  The current lineup includes, among other items:

  • ET 43 – Reflective tape, 60 cm
  • ET 434 – Hollow cone rubber probe
  • ET 435 – Pointed rubber probe
  • ET 436 – Combined meter/feet-per-minute counter
  • ET 437 – Complete rotary axis
• What are the advantages of a device that combines optical and mechanical measurements?

  The user can adapt the measurement method to the specific situation.

  Noncontact measurement is particularly suitable for visually accessible rotating components.

  Contact measurement is an alternative for suitable shafts or surfaces.

  The impeller can also be used to measure linear velocity.

  This allows a single measuring device to cover multiple workshop applications.

• What other measuring instruments are useful additions to a tachometer?

  Depending on the diagnostic task, tools such as digital thermometers for workshop and vehicle diagnostics, compression pressure testers, engine pressure loss testers, or other engine testers may be useful.

  You can find additional mechanical testing and service equipment under Test, Diagnostic, and Service Equipment for Internal Combustion Engines.