Extech 461995 Laser Photo and Contact Tachometer, 99,999 RPM

461995 is the Extech laser photo and contact tachometer. In photo mode a Class 2 laser pointer reads reflective tape on a rotating part from 50 mm to 2000 mm away for 10 to 99,999 rpm; in contact mode a rotating ring or surface speed wheel measures rpm and linear speed. Accuracy is 0.05 percent of reading plus one digit for rpm.

Two ways to read rpm from one hand-held meter

Where it is safe to touch the shaft, the contact ring or surface speed wheel gives rpm from 0.5 rpm and linear surface speed in ft/min (0.2 to 6560) or m/min (0.05 to 1999.9). Where the shaft is hot, moving too fast or out of reach, the laser beam reads a square of reflective tape attached to the rotating part, from 2 to 79 inches away.

The display reverses character direction depending on the mode, so the digits can be read with the meter held either way. Last, maximum and minimum readings are stored while the measure button is held and recalled with the memory key, and cleared after about 10 seconds of inactivity.

Features stated in the datasheet and manual

• Large 0.4 in (10 mm) 5-digit LCD; quartz crystal time base for accuracy.
• Photo range 10 to 99,999 rpm; resolution 0.1 rpm below 1000 rpm and 1 rpm above.
• Memory for last, maximum and minimum readings.
• Supplied with contact tips and wheel, four AA batteries, reflective tape and carrying case.

Technical specification

Range and accuracy (manual)

General specification

Choosing between 461895 and 461995

The companion model 461895 shares the same datasheet but lacks the laser beam; it reads 5 to 99,999 rpm in photo mode. The 461995 adds the narrow-beam laser for non-contact measurements from up to 6.5 ft (2 m) and starts at 10 rpm. NIST certificate versions are ordered as 461995-NIST.

If the target rotates slowly, the manual advises adding more squares of tape and dividing the reading by the number of tape squares to find true rpm when the display shows below 50.

Operating and safety notes from the manual

Photo mode: stick reflective tape on the part, set the function switch to PHOTO, aim the laser at the tape from 50 to 2000 mm, press and hold the measure button and release when the reading stabilises. Bright ambient light can interfere; shade the target area if required.

Contact mode: press the ring lightly against the centre of the shaft, hold the measure button and release after about two seconds. Never point the laser at eyes or use it near explosive gases, and take extreme care with rotating machinery.

Typical uses in Gulf plants

General engineering note: tachometers are used to confirm pump, fan, conveyor and motor speeds after drive or pulley changes, check VFD display accuracy, and measure surface speed on belts, rollers and line shafts. The non-contact mode avoids touching rotating parts and is useful on ventilation fans and cooling tower fan shafts.

Related Extech items

For vibration screening of the same machines see the VB450 and for temperature the IR400. See the portable test and measurement category.

Field use and calibration notes

Tachometers are used in the region by maintenance teams in water plants, power stations, factories and HVAC plant rooms to check the speed of motors, fans, pumps, conveyors and belts. For photo mode, fix a small piece of reflective tape on the rotating part and keep the rest of the surface dark, so the meter sees only one reflection per turn. For contact mode, keep the meter in line with the shaft and apply only light pressure.

Always keep hands, loose clothing and the meter away from moving parts, and never look into the laser beam. Use the surface speed wheel to check belt and conveyor speeds. Arrange calibration at regular intervals where readings are used for reports or acceptance tests.

Store the meter in its case and replace the batteries when the low battery indicator appears.

Information to send with an enquiry

• Machine types and speed ranges
• Calibration certificate requirement
• Quantity

Related Extech products: Extech VB450 Pocket Vibration Meter, 10 Hz to 1500 Hz, Extech PQ3450 3-Phase Power Analyzer and Datalogger, Extech IR400 Mini IR Thermometer with Laser Pointer, 332 C, Extech EX820A 1000 A True RMS AC Clamp Meter with IR Thermometer, Extech LT300 Digital Light Meter, 400,000 Lux and Extech EX530A Heavy Duty True RMS Multimeter, 50000 Count.

Documents and quotation

This page carries the official Extech datasheet and manual for 461995. Seven Star LLC is an independent supplier in Muscat and sources Extech products on request; tell us the quantity and delivery point to receive a quotation. Always confirm the order code and technical values in the documents first. See more in the product category.