Extech Instruments 461895 User manual

INSTRUCTION MANUAL
English / Espanola
Model 461895
COMBINATION CONTACT/PHOTO TACHOMETER
1. INTRODUCTION
Congratulations on your purchase of Extech's Combination Contact/Photo Tachometer,
Model 461895. The combination tachometer is a patented design providing contact and
non-contact RPM measurements. In addition, linear surface speeds can be measured in
ft/min. or m/min.
Features
•Use of an exclusive micro-computer LSI-circuit and crystal time base offers high 0.05%
accuracy and fast measuring time
•RPM measurements span wide ranges: 5 to 99,999 RPM for photo tachometer and 0.5
to 20,000 RPM for contact tachometer
•Suppression of insignificant zeroes in large, 5 digit LCD display provides exact RPM
while saving battery power
•Last value and last max/min readings can be automatically stored and recalled
actoolsupply.com
actoolsupply.com
actoolsupply.com
Extech 461895 Combination Contact Photo Tachometer
Extech 461895-NIST Combination Contact Photo Tachometer

461895 V1.8 August 2001
2
2. SPECIFICATIONS
2-1 General Specifications
Circuit Custom one-chip LSI microprocessor circuit.
Time base Quartz crystal
Display 5 digit, 10 mm (0.4") LCD display with function annunciation
Measurement Photo Tachometer - 5 to 99,999 rpm
Contact Tachometer - 0.5 to 19,999 rpm
Surface Speed - 0.2 to 6,560 ft/min
Surface Speed - 0.05 to 1,999 m/min
Memory Last value, last max. reading, last min. reading
Sampling Time Photo Tachometer - 1 sec. (over 60 rpm)
Contact Tachometer - 1 sec. (over 6 rpm)
Detecting Distance -
Photo Tachometer
50 to 150 mm (2 to 6 inches) depending on ambient light
Operating Temperature 32 °F to 122 °F (0 °C to 50 °C)
Power Supply 4x 1.5 V AA (UM 3) batteries
Weight 0.66 lbs. / 300g (including battery)
Size 8.5 x 2.6 x1.5” (215 x 65 x 38mm)
Accessories Reflective tape (23"), cone and funnel rpm adaptor, surface
speed test wheel, and carrying case
2-2 Electrical Specifications
Measurement Range Resolution Accuracy (% rdg)
Photo
Tachometer
5 to 99,999 rpm 0.1 rpm (0.5 to 999.9 rpm)
1 rpm (over 1000 rpm)
Contact
Tachometer
0.05 to 19,999 rpm 0.1 rpm (0.5 to 999.9 rpm)
1 rpm (over 1000 rpm)
+ (0.05% + 1 digit)
Surface
Speed
0.2 to 6560 ft/min 0.1 ft/min (0.1 to 999.9 ft/min)
1 ft/min (over 1000 ft/min)
Surface
Speed
0.05 to 1999.9
m/min
0.01 m/min (0.05 to 99.99 m/min)
0.1 m/min (over 100 m/min)
± (1% rdg + 1d)
3. FRONT PANEL DESCRIPTION
3-1 Reflective tape
3-2 Signal light beam
3-3 Monitor indicator
3-4 Display
3-5 Measure button
3-6 Memory button
3-7 Function switch
3-8 Rotating ring
3-9 Circumferential speed ring
3-10 Battery compartment
3-1
3-2
3-3
3-4
3-6
3-7
3-8
3-9
3-5
3-10
actoolsupply.com
actoolsupply.com

461895 V1.8 August 2001
3
4. OPERATION
4.1 Photo Tachometer
a) Slide the Function Switch to the "rpm PHOTO" position.
b) Apply a 0.5” (12mm) square piece of reflective tape to the object being measured.
c) Press the Measure button and align the visible light beam with the object being
measured. Check that the Monitor Indicator lights when the reflective tape
passes through the light beam. Release the Measure button once the display
stabilizes (approx. 2 seconds). For best results, hold the meter's light source 6 -
12" from the object being measured (low ambient light recommended).
d) If the RPM measurement is less than 50, apply additional squares of reflective
tape (equidistant). Divide the reading shown on the display by the number of
reflective squares to get the actual RPM.
NOTE: Bright ambient light may interfere with the reflected light beam. Shading the
target area may be necessary in some cases.
CAUTION: Rotating objects can be dangerous. Use extreme care when holding the
meter near any such object.
4.2 Contact Tachometer
a) Slide the Function Switch to the "rpm CONTACT" position.
b) Press the Measure button while lightly pressing the rotating ring against the
center opening of a rotating shaft. Release the Measure button once the display
has stabilized (approx. 2 seconds).
4.3 Surface Speed Measurement
a) Slide the Function Switch to "SURFACE SPEED ft/min" or "m/min".
b) Affix the Surface Speed Wheel on the meter shaft.
c) Press the Measure button and hold the surface speed wheel against the device
being measured. Release the Measure button once the display has stabilized
(approx. 2 seconds).
4.4 Memory Recall
When measuring, the last reading and last max and min values are automatically
stored before the Measure button is released. Recall the values by pressing the
Memory button the appropriate number of times (see below).
a) Press once and hold - the last value is displayed followed by "LA"
b) Press again and hold - the maximum value is displayed followed by "UP"
c) Press again and hold - the minimum value is displayed followed by "dn"
5. BATTERY REPLACEMENT
5.1 The low battery indication appears as a "LO" on the display.
5.2 To replace the battery:
a) Loosen the screw on the battery cover (3-10, Fig. 1) and remove.
b) Replace with 4 x 1.5V AA batteries and replace cover.
actoolsupply.com
actoolsupply.com

461895 V1.8 August 2001
4
6. CALIBRATION / REPAIR SERVICES
Extech offers complete repair and calibration services for all of the products we sell.
For periodic calibration, NIST certification or repair of any Extech product, call customer
service for details on services available. Extech recommends that calibration be
performed on an annual basis to insure calibration integrity.
7. WARRANTY
EXTECH INSTRUMENTS CORPORATION warrants this instrument tobe free of defects in parts and
workmanship for one year from date of shipment (a six month limited warranty applies on sensors and
cables). Ifit should become necessary to return the instrument for service during or beyond the warranty
period, contact the Customer Service Department for authorization. A Return Authorization (RA) number
must be issued before any product is returned to Extech. The sender is responsible for shipping charges,
freight, insurance and proper packaging to prevent damage in transit. This warranty does not apply to
defects resulting from action of the user such as misuse, improper wiring, operation outside of
specification, improper maintenance or repair, or unauthorized modification. Extech specifically disclaims
any implied warranties or merchantability or fitness for a specific purpose and will not be liable for any
direct, indirect, incidental or consequential damages. Extech's total liability is limited to repair or
replacement of the product.
The warranty set forth above is inclusive and no other warranty, whether written or oral, is expressed or
implied.
actoolsupply.com
actoolsupply.com