Fluke 931 Contact and Non-Contact Tachometer

Fluke 931 Overview

Some shafts can be reached with a contact tip, some can only be seen through a guard, and conveyors need linear speed rather than RPM. The Fluke 931 covers all three cases in one handheld tool: optical (non-contact) RPM measurement with reflective tape, contact RPM with a cone tip, and surface speed or length with the measuring wheel. Fluke rates both modes at ±0.02% of reading ±1 digit.

In the UAE, maintenance teams often use the 931 on chilled-water pumps, AHU and cooling-tower fans and plant conveyors, where one tool has to cover guarded shafts, exposed shafts and belt speed.

Who Needs the Fluke 931?

Fluke positions the 931 for maintenance work in:

• Heavy manufacturing, machining and chemical plants
• Water purification and pumping stations
• HVAC systems, for example compressor and fan speed checks
• Any site that needs belt or conveyor surface speed as well as shaft RPM

Fluke 931 Key Features

What the 931 brings over a single-mode tachometer:

• Two measuring methods in one tool: optical up to 99,999 RPM and contact up to 19,999 RPM
• Surface speed in m/min, ft/min or m/s, and length up to 99,999 m, ft or in, using the measuring wheel
• ±0.02% of reading ±1 digit accuracy in both RPM modes
• Optical sensing distance of 500 mm (20 in), keeping hands away from rotating parts
• Memory recalls the maximum, minimum, average and last reading
• Runs about 40 hours on two AA batteries; 250 g and 175 x 60 x 28 mm

Fluke 931 Applications

Typical measurements with the Fluke 931:

• Verifying motor and pump shaft speed after a drive or pulley change
• Checking fan and compressor speed during HVAC commissioning
• Measuring conveyor, roller and belt surface speed with the wheel
• Measuring lengths of material on production lines

Only need non-contact RPM? The Fluke 930 is the optical-only model. Other tachometers in our tachometer range include the Testo 470 and Testo 460. More Fluke tools are on our brand page.

What comes with the Fluke 931

Fluke’s product page lists:

• Fluke 931 tachometer
• 0.1 m measuring wheel
• Conical head and inner-cone head for contact RPM
• Lengthening rod
• 10 reflective strips for optical measurement

The users manual also mentions a 6 in wheel; please confirm the exact box contents with us when ordering.

Fluke 931 Specifications

Key figures from Fluke’s specifications for the 931:

Fluke 931 FAQ

Questions about the Fluke 931:

What is the difference between the Fluke 930 and 931?

The 930 measures RPM optically only. The 931 adds contact RPM, surface speed and length with the included tips and wheel.

How far away can I measure optically?

Fluke specifies an optical sensing distance of up to 500 mm, with a reflective strip on the rotating part.

Can it measure belt speed?

Yes. With the measuring wheel held against the belt it reads surface speed in m/min, ft/min or m/s.

What powers it and for how long?

Two AA batteries, for about 40 hours of use.

Choosing the Fluke 931 with MME

Not sure whether you need contact, optical or surface-speed readings? MME can compare the Fluke 930, the 931 and other tachometers against your machines. Contact us for a quote.