LABORATORY PRECISION IN A PORTABLE UNIT The Mark 3 Tachometer Tester not only has all the test capabilities required for two pole and four pole engine tachometers, but also provides stable and precise low speeds in the 100 rpm region for items such as wheel speed sensors. The drive pad speed ranges have been selected to accommodate both types of tachometer generators. Drive pad rotation is selectable in either clockwise or counterclockwise direction. The Mark 3 Tachometer Tester provides dual AND 20005 Type XV-B mounting pads with a speed range of 0 to 5000 RPM on one pad and 0 to 2500 rpm on the other. The tachometer tester's precision closed loop drive system regulates the drive speed within plus or minus 1RPM of SET SPEED from no load to full load from 100 to 5000 rpm and a line voltage change of +/-10%. The digital speed indicator is switch selectable to read the speed of each tachometer testing pad directly in RPM or in PERCENT. The read out accuracy is 0.01% plus or minus one least significant digit. To provide certainty of measurement at extremely low speeds the low speed pad indicates speed to 1/10th of one rpm throughout its range. A three phase switch selectable precision resistive load bank is provided internally. The loads are 20 or 40 ohms three phase Y connected or 15 or 30 ohms Delta connected. A load "OFF" position permits using the mounted generator to test indicators. A digital voltmeter is also mounted on the instrument panel. The meter is provided with a selector switch to select between phases.

• Power requirements - 120 volts 50/60 hz. 3 amps.
• Also available - 220-240 volts 50hz. or 120 volts - 400 hz.
• Drive pads - Two each AND 20005 Type XV-B
• Drive speed - 0 to 5000 rpm adjustable by both coarse and fine controls.
• Both Clockwise and Counterclockwise rotation.
• Voltmeter, digital - 0 to 30 volts AC selectable to all three phases.
• Speed indication - Selectable, each drive pad or percent
• Load banks - Three phase resistive, switch selectable, 20 or 40 ohms three phase Y connected or 15 or 30 ohms delta connected.
• Voltmeter accuracy - Plus or minus 0.05% of reading plus two least significant digits.
• RPM indicator accuracy - Crystal accuracy (0.01%) plus or minus one rpm in both 0-5000 range and 0-2500 range, 1/100% in percent range.
• Drive Regulation - Load: Plus or minus 1 RPM, 100 to 5000 rpm, no load to full load.
• Drive Regulation - Line: Plus or minus ½% for 10% line change.
• Adapters - Cable adapters are provided for connection to both two and four pole tachometers.
• Dimensions: 20" Wide X 10 1/2" Deep X 11 1/2" High
• Net Weight: 30 lbs (14 kg)