461831 - Tachometer Extech - Free user manual and instructions

Product Type	Digital Stroboscope Tachometer
Brand	Extech
Model	461831
Measurement Range	100 to 10,000 RPM/FPM
Resolution	0.1 (<1000 RPM), 1 (1000-9999 RPM), 10 (10,000 RPM)
Accuracy	±(0.05% + 1 digit)
Display	4-digit (10,000 count) LED display
Flash Tube Type	Xenon lamp
Flash Energy	4 Watt-Seconds (Joules)
Flash Duration	60 to 1000 microseconds
Flash Color	White 6500°K
Beam Angle	80°
Range Selection	LOW (100-1000 RPM) and HIGH (1000-10,000 RPM)
Adjustment Controls	COARSE and FINE knobs
Power Supply	220VAC, 50/60Hz ±10%
Power Consumption	Less than 25 watts at 115V
Operating Temperature	32 to 122°F (0 to 50°C)
Operating Humidity	Less than 80% RH
Dimensions	8.3 x 4.8 x 4.8 inches (21 x 12 x 12 cm)
Weight	2.2 lbs (1 kg)
Housing Material	Impact resistant plastic with plastic lens and mirrored reflectors
Circuit	Exclusive one-chip LSI with crystal time base
Sampling Time	1 second
Usage Limits	30 min max below 3000 rpm, 5 min max above 3000 rpm; 10 min cool-down
Warranty	One year from shipment (6 months on sensors and cables)

Frequently Asked Questions - 461831 Extech

How do I measure RPM using the Extech 461831?

Remove power to the device under test. Affix a reflective mark (e.g., supplied reflective tape). Point the strobe beam toward the mark. Adjust the COARSE and FINE knobs until the mark appears stationary. Read the RPM value on the LED display. Ensure only one stationary mark appears to avoid harmonic errors.

What is a harmonic measurement and how do I avoid it?

A harmonic occurs when the strobe flash rate is a multiple or fraction of the actual speed, causing multiple stationary images. To avoid, adjust the knobs until you see two images (doubled harmonic), then reduce flash rate until only one stationary image appears. This single image indicates the true RPM.

What are the operating time limits for the Xenon lamp?

For speeds <3000 rpm, maximum continuous operation is 30 minutes. For speeds ≥3000 rpm, maximum is 5 minutes. Always allow a 10-minute cool-down between cycles to prevent damage to the instrument and prolong lamp life.

How do I replace the Xenon lamp?

Replace the Xenon lamp when readings become irregular. First, unplug the instrument. Refer to the manual for disassembly instructions. Avoid touching the glass tube of the new lamp. Use only an authorized Extech replacement lamp.

What does the flashing decimal on the display indicate?

A flashing decimal point on the far right of the LED display indicates that the reading exceeds 10,000 RPM. In this case, multiply the displayed value by 10 to obtain the actual RPM.

Can I use the 461831 for visual inspection of moving parts?

Yes. Once you achieve stop-motion (flash rate matches the object's speed), you can use the FINE adjust knob to vary the viewing perspective. This allows you to inspect gears, fans, propellers, etc., as if they were stationary. Note the time limits for prolonged use.

What is the difference between models 461830 and 461831?

The primary difference is the power supply: Model 461830 operates on 110VAC, while Model 461831 operates on 220VAC. Both are 50/60Hz. All other specifications are identical.

How do I clean and maintain the stroboscope?

Clean the exterior with a soft, dry cloth. Do not use solvents or abrasive cleaners. Keep the lens and reflector free of dust. For internal maintenance, contact Extech service. Always observe the usage time limits to avoid overheating.

What is covered under the warranty?

Extech warrants the instrument to be free from defects in parts and workmanship for one year from the date of shipment (six months for sensors and cables). The warranty excludes misuse, improper wiring, operation outside specifications, or unauthorized modifications.

How can I get technical support or repair service?

Contact Extech Customer Service at [phone]. For technical support, dial extension 200 or email [e-mail]. For repairs/returns, dial extension 210 or email [e-mail]. A Return Authorization (RA) number is required before returning any product.

USER MANUAL 461831 Extech

Digital Stroboscope Tachometer

Model 461830 and Model 461831

Line drawing of a handheld device with a circular lens and attached rectangular casing (no text or symbols)

Warranty

EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and workmanship for one year from date of shipment (a six month limited warranty applies on sensors and cables). If it should become necessary to return the instrument for service during or beyond the warranty period, contact the Customer Service Department at [phone] ext. 210 for authorization or visit our website at www.extech.com (click on 'Contact Extech' and go to 'Service Department' to request an RA number). 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.

Introduction

Congratulations on your purchase of the Extech Digital Stroboscope Tachometer. This device measures the speed of moving parts such as gears, fans, propellers, centrifuges, and pumps. The stop-motion action of this instrument permits the visual inspection of moving parts. Careful use of this instrument will provide years of reliable service.

Safety

This symbol, adjacent to another symbol or terminal, indicates the user must refer to the manual for further information.

This symbol, adjacent to a terminal indicates that, under normal use, hazardous voltages may be present

WARNING: Do not look directly at the Strobe's Xenon lamp or its reflector.

WARNING: This device causes moving objects to appear still. Take precautions against accidental contact with moving objects.

CAUTION: Do not touch the flash tube.

General Specifications

Circuit Exclusive one-chip	LSI circuit with crystal time base
Display	4-digit (10,000 count; 0 to 9999) LED display
Measurement unit	RPM (revolutions or rotations per minute) is the speed of the moving device under test which equals the FPM rate (strobe flashes per minute)
Operating Temperature 32 to 122°F (0 to 50°C)
Operating Humidity < 80% RH
Power Supply	110VAC (461830) or 220VAC (461831) 50/60Hz ±10%
Power Consumption <25 watts @ 115V
Weight 2.2 lbs. (1kg)
Dimensions	8.3 x 4.8 x 4.8" (21 x 12 x 12cm)
Housing construction	Impact resistant plastic with plastic lens and mirrored reflectors

Electrical Specifications

Measurement Range 100 to 10,000	RPM/FPM
Resolution 0.1 (<1000 RPM/FPM)	1 (1000 to 9999 RPM/FPM)10 (10,000 RPM/FPM)
Accuracy ± (0.05% + 1 digits)
Sampling Time 1 second
Strobe Flash adjust range	LOW: 100 to 1,000 RPM/FMPHIGH: 1000 to 10,000 RPM/FPM
Strobe Flash tube type	Xenon lamp
Strobe Flash duration	60 to 1000 microseconds
Strobe Flash Energy	4 Watt-Seconds (Joules)
Strobe Beam Angle	80°
Strobe Flash Color	White 6500°K

Notes: Replace the Xenon lamp when readings appear irregular. To prolong the Xenon lamp life and ensure safe operation, please adhere to the following recommendations.

• A 30-minute use limit < 3000rpm and 5-minute use limit > 3000rpm exists. Do not use the instrument for periods longer than specified otherwise damage to the instrument may result.
  • Always permit a 10-minute cool-down between cycles.
  • Do not touch the Xenon flash tube.

• Xenon lamp

• LED Display
• Grip handle

• COARSE adjust knob

• FINE adjust knob

• Power ON/OFF switch
• Range Select Switch
• AC power cord and jack

Powering the instrument

1. Plug the supplied power cable into the instrument's power cable jack.
2. Plug the other end of the cable into an appropriate AC power source. The Model 461830 requires 110VAC and the 461831 requires 220VAC. Do not plug the device into an incorrect power source otherwise damage to the instrument will result.
3. Use the ON/OFF switch to turn the instrument on or off.

Speed (RPM) Measurements

1. Remove power to the device under test so that it is stationary.
2. Affix a reflective mark or place a small piece of the supplied reflective tape on the device under test.
3. Point the Stroboscope's beam toward the reflective mark.
4. Use the 'FINE' and 'COARSE' adjustment knobs to synchronize or "stop" the motion of the reflective mark (read the 'Display Notes' section below).
5. Read the RPM value on the LED display.

Range Adjustments

1. While measuring, use the RANGE button to select the range as desired
2. The LOW range is used for measurements below 1,000 RPM. The HIGH range is used for measurements above 1,000 RPM.

Display Notes for Speed Measurements

Care must be taken to ensure that the reflective mark is providing a 1:1 measurement.

Check that there is only one mark and not two, four, or more stationary marks on the object under test.

Two or more stopped marks indicate a 'harmonic' measurement (2:1, 3:1, 4:1 etc.) and the instrument will display double, triple, or quadruple the actual speed. A useful method of avoiding harmonic measurements is to adjust the FINE/COARSE knobs until two images (reflective marks) appear and then lower the flash rate (via COARSE/FINE knobs) until a single, stationary image appears. This will be the actual speed.

In the example below, a rotating shaft is affixed with one piece of reflective tape. The illustrations below represent several possible images that would appear when the strobe beam is pointed to the shaft.

If more than one reflective mark appears (as in columns 3, 4, and 5 below) the image is showing a 'harmonic'. The bold column (column 2) shows the actual speed of the shaft.

Column 1 shows a harmonic whereby the actual speed is divided in half. Because of this, it is good practice to adjust the 'FINE' and 'COARSE' knobs until you can see the 'doubled harmonic' (Column 3) and then the 'halved harmonic' (Column 1) and then find the setting in-between (Column 2 in bold).

Note that the LED display has an AUTO RANGE INDICATOR (flashing decimal at the far right) that appears when the readings are over 10,000 RPM. In these cases, multiply the displayed reading by 10.

Visually inspecting a moving object (stop-motion)

When the speed of the moving object matches the flash rate of the stroboscope, the moving object appears still. Measure the speed of a moving object as described in the previous sections to obtain a stop-motion. Once stop-motion is achieved, the FINE adjust knob is used to vary the viewing perspective of the object under test for visual inspection.

Important note on Test Durations

The Xenon lamp used in this instrument has time restrictions on usage. If the specified test times and cool-off periods (shown in the table below) are not observed, damage to the instrument can result and the life span of the lamp can be shortened.

RPM Max.	Operating Time Cool-Off	Time
< 3,000 rpm 30	minutes	10 minutes
> 3,000 rpm 5	minutes

Extech offers repair and calibration services for the products we sell. Extech also provides NIST certification for most products. Call the Customer Service Department for information on calibration services available for this product. Extech recommends that annual calibrations be performed to verify meter performance and accuracy.

Support Hotline [phone]

Tech support: Ext. 200; Email: [e-mail]

Repair/Returns: Ext. 210; Email: [e-mail]

Website: www.extech.com

Copyright © 2003 Extech Instruments Corporation

All rights reserved including the right of reproduction in whole or in part in any form.