Model 21 Multidial www.vishay.com Vishay Spectrol Mounting Instructions PRINCIPLES OF OPERATION The inner scale of the Model 21 Multidial is graduated in hundredths of a turn. The outer scale (read through the viewing window) counts the number of turns (0 to 15) that have been completed. Example: If the numeral in the window reads 7 and the inner scale reads 21, the reading is 7 turns plus 21/100 of the eighth turn. In the case of a 10-turn potentiometer, this equals 72.1 % of 10 turns. Each complete revolution of the inner scale transfers the outer scale numerals in the window. Numeral transfer on the outer scale occurs between 94 and 0 on the inner scale. MOUNTING INSTRUCTIONS The following instructions apply when the Model 21 Multidial is used on a 1/8" panel in conjunction with Spectrol 800 series potentiometers. It may be necessary to modify these instructions when using the Model 21 Multidial with other than 1/8" panel thicknesses or multiturn devices having different mounting and/or shaft dimensions: 1. Turn the shaft of the potentiometer against its counterclockwise stop. 2. Turn the inner scale of the Model 21 Multidial so that “0” appears in the viewing window and the inner scale reads higher than 10. 3. With the braking lever released (in the counterclockwise position) slip the Model 21 Multidial over the potentiometer shaft. The locating lug on the multidial should enter the potentiometer locating lug hole in the panel. 4. Seat the Model 21 Multidial lightly against the panel. 5. Turn the inner scale counterclockwise slowly until “0” of the inner scale is opposite the index mark. Then tighten the recessed set screw firmly against the potentiometer shaft. 6. The dial is now ready to operate. Note • The locating lug on the Model 21 Multidial is designed to occupy the same panel hole that accommodates the potentiometer locating lug. In instances where cabinet panels are less than 1/8" in thickness, it may be necessary to file or grind off part of the locating lug of either the Model 21 Multidial or the potentiometer. In instances where the Model 21 Multidial is used with other than Spectrol 800 series potentiometers, it may be necessary to drill a 1/8" hole 0.562" directly below the horizontal centerline of potentiometer mounting hole to accent the locating lug. Mounting face 1.000 (25.40 ± 0.015 ± 0.38) Drive sleeve Brake lever Counting dial 22° ± 5° 1.094 R max. (27.79) 46° ± 5° 0.046 + 0.000 - 0.015 + 0.00 (1.17 - 0.38 ) 0.128 (3.25) Ø 1.812 (46.02) Base Graduated dial 0.268 + 0.015 - 0.000 (6.81 - 0.00 ) 0.578 + 0.015 - 0.000 (14.68 + 0.38 + 0.38 - 0.00 ) 0.922 ± 0.031 (23.42 ± 0.79) Panel Locking lever Set screw* Spectrol multiturn potentiometer Model 21 multidial *Set screw location at no 75 on dial face Locating lug Potentiometer locating lug hole Dimensions in inches (millimeters) Revision: 10-Aug-12 Document Number: 57110 1 For technical questions, contact: [email protected] THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000