
User’s Guide
Contact Tachometer
Model 461891
• Measures from 0.5 to 19999 rpm
• Min/Max Memory Recall
• Cone, funnel, surface attachments included
• Quartz crystal time base
99 Washington Street
Melrose, MA 02176
Phone 781-665-1400
Toll Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com
Back to the Extech 461891 Product Page
Introduction
Congratulations on your purchase of Extech’s Digital Tachometer. This professional meter,
with proper care, will provide years of safe reliable service.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX 781.665.0780 - TestEquipmentDepot.com

Specifications
General Specifications
Circuit
Custom one-chip LSI microprocessor circuit
Time base Quartz crystal
Display 5-digit multi function LCD display
Measurements Rotation Speed 0.5 to 19,999 rpm
Surface Speed 0.2 to 6560 ft/min.
0.05 to 1999.9 m/min
Memory Last and Max/Min readings
Sampling Time 1 second
Operating Temperature/RH 32 °F to 122 °F (0 °C to 50 °C) / <80% RH
Power Supply 4 x 1.5V AA batteries
Power Consumption Approx. 10 mA
Weight 0.62 lb (280 g) including batteries
Dimensions 8.2 x 2.8 x1.5" (208 x 72 x 37 mm)
Accessories Cone rpm adaptor, funnel rpm adaptor, surface speed
Range Specifications
rpm 0.5 to 19,999 rpm 0.1 rpm (0.5 to 999.9 rpm)
ft/min 0.2 to 6560 ft/min 0.1 ft/min (0.2 to 999.9 ft/min)
m/min 0.05 to 1999.9 m/min 0.01 m/min (0.05 to 99.99 m/min)
Range Resolution Accuracy
test wheel, and carrying case
1 rpm (over 1000 rpm)
1 ft/min (over 1000 ft/min)
0.1 m/min (over 100 m/min)
+
(0.05% rdg +1d)
@23+
± (1% rdg + 1 digit)
5oC
2
461891 Ver. 1.9 7/02