Extech 461750 Operating Manual

User's Guide

Mini Photo Tachometer Model 461700
Mini Contact Tachometer Model 461750

Introduction

Congratulations on your purchase of the Extech Tachometer.
The Model 461700 Photo Tachometer uses precision optics and reflective tape to

measure the RPM of rotating devices such as fans and gears.
The Model 461750 Contact Tachometer uses convex and concave attachments to

measure RPM. It also has a built-in wheel to measure the linear surface speed of moving
devices such as conveyors and treadmills. Careful use of this tachometer will provide
years of reliable service.

Specifications

General Specifications

Display 5-digit LCD Display
Range selection Automatic range selection
Time Base 4MHz Quartz Crystal
Sampling Time 1 second (>60 rpm); >1 second (10 to 60 rpm)
Photo Tachometer Distance 2 to 12” (5 to 30cm)
Operating Temperature 32 to 122
Operating Humidity 80% RH Max.
Power supply 9V Battery
Battery Life 40 hours (approx.)
Applicable standards EN 50081-1/1992 (EN 55022)
EN 50082-1/1997 (EN 55024)
Dimensions 461700: 4.9 x 2.0 x 1.3” (124 x 51 x 33mm)
461750: 5.9 x 2.0 x 1.3” (150 x 51 x 33mm)
Weight 461700: 4.0 oz. (114g); 461750: 5.0 oz. (142g)

o

F (0 to 50oC)

Range Specifications

Measurement Range Accuracy

Rotation
(461700 Photo)
Rotation
(461750 Contact)

Surface Speed
(461750)

10.000 to 99999 rpm ± (0.1% reading + 2 digits)

10.000 to 9999 rpm ± (0.1% reading + 2 digits)

3.0000 to 6560.0 ft/min

1.0000 to 1999.9 m/min

1.0000 to 5000.0 yds/min

2

± (1.5% reading + 2digits)

461700 / 461750 Version 2.3 Mar 2004

Meter Description

1. RPM adaptor (461750 only)

2. Wheel for linear surface measurements (461750 only)

3. Adaptor shaft (461750 only)

4. Model 461700 optics

5. Hand Guard (461750 only)

6. Power ON/OFF and HOLD button

7. Unit of measure selection button (461750 only)

8. LCD Display

9. Alternate Power ON/OFF button
Note that the battery compartment is located

on the rear of the instrument

Display Description

1. Low Battery

2. Data Hold

3. Rotations per minute

4. Meters per minute
Feet per minute
Yards per minute

3

461700 / 461750 Version 2.3 Mar 2004