920, 930, 940 SERIES Precision Motor Potentiometers BI Motor Potentiometers use a precision potentiometer connected to a DC motor by a gear box and clutch. There are eight potentiometer types and 15 gear ratios available combined with a 10,700 RPM motor. 2 In addition, motor potentiometers with special features such as center-taps, multi-taps, special shafts, and special gear ratios, etc., can be provided on special orders. Several potentiometer sections can be ganged on a single rotor potentiometer shaft. SPECIFICATIONS Motor Potentiometer Model Potentiometer Model # of Turns Element Type Potentiometer Mounting Style Resistance Range, Ohms Diameter Linearity No. of Gangs, Max. Motor Potentiometer Model Potentiometer Model # of Turns Element Type Potentiometer Mounting Style Resistance Range, Ohms Diameter Linearity No. of Gangs, Max. 922 6671 1 Conductive Plastic Bushing 1K-300K 2” ±0.25% 927 8146 10 Hybrid 929 8211 1 Hybrid 931 A 10 Wirewound Bushing 1K-100K 7/8” ±0.25% Bushing 1K-25K 2” ±0.5% 3 2 3 Bushing 10-500K 1 -13/16” <300Ω: ±0.5% ≥300Ω: ±0.25% 3 933 C 3 Wirewound Bushing 100-100K 1-13/16” ±0.5% ≥1KΩ:0.20% 3 936 7283 10 Wirewound Servo 100-100K 7/8” ≤75Ω:±0.50% 937 7286 10 Wirewound Bushing 100-100K 7/8” ±0.25% 2 2 949 5611 1 Wirewound Bushing 1K - 50K 2” <50Ω: ±1.0% ≥50Ω: ±0.5% 3 Specifications subject to change without notice. Refer to potentiometer data sheet for complete specifications. 2-25 Model 920, 930, 940 Series MOTOR SPECIFICATIONS Rotor Temperature, °C Input Voltage Range, Vdc Input Voltage, Nominal, Vdc Power Input @ Stall (6 Vdc), Watts No Load Current, mA Armature Resistance, Ohms No Load Speed @ Max. Volts, RPM No Load Speed (6.0 Vdc, RPM) Mechanical Time constant @ Max. Supply Voltage, Sec. Starting Voltage, Vdc Torque Constant, oz.-in. Torque Stall (6.0 Vdc), oz.-in. Max. Torque Continuous Duty (Gear Box), oz.-in. Max. Moment of Inertia, oz.-in. /Sec2 Motor Pot Life Expectancy @ Rated Torque, Hours Slip Friction Setting, oz.-in., Nominal Life Reduction per Load Torque Beyond Rating, Estimated Hours 22 Vis to 9.0 6.0* 1.8 ≤7 20 16,000 10,700 0.032 0.3 0.749 0.22 3 5.6 x 10-6 5,000 12 643 (TL-3) *Input voltage in continuous stall and 22°C ambient. GEAR RATIO SPECIFICATIONS Gear Ratio (N) 41:1 76:1 141:1 262:1 485:1 900:1 1,670:1 3,101:1 5,752:1 10,683:1 19,813:1 36,796:1 68,245:1 126,741:1 235,067:1 Output Speed (RPM) 261 141 76 41 22 12 6.4 3.5 1.9 1.0 0.54 0.29 0.17 0.08 0.05 Efficiency (e) .73 .66 .66 .59 .59 .53 .53 .48 .48 .43 .43 .39 .39 .35 .35 Backlash Max. (B) 4° 4° 4° 4° 4° 4° 4° 4° 4° 4° 4° 4° 4° 4° 4° Direction(D)** CW CCW CCW CW CW CCW CCW CW CW CW CCW CW CW CCW CCW ** Direction of shaft rotation with “+” voltage to red lead. 2-26 Model 920, 930, 940 Series PERFORMANCE Output Speed vs. Gear Ration at various Load Torques 200 2.5 IN-OZ 0.0177 N-M 100 2 50 40 30 5 IN-OZ 0.0353 N-M 20 10,700 RPM MOTOR 10 IN-OZ 0.0706 N-M 7.5 IN-OZ 0.0530 N-M 10 5 4 3 2 1 0.5 0.4 0.3 0.2 0.1 0.05 0.04 0.03 0.02 0.01 10 100 1K 10K 100K 1MEG Gear Ratio (X:1) 41 76 141 262 485 900 1670 3120 5750 10.7K 19.8K 37K 68.2K 127K 235K (.73) (.66) (.66) (.59) (.59) (.53) (.53) (.48) (.48) (.43) (.43) (.39) (.39) (.35) (.35) Specific Ratios (Efficiency) 2-27 Model 920, 930, 940 Series OUTLINE DIMENSIONS (Inch/mm) Models 922, 929 & 949 (Potentiometer Models 6671 & 5611) "A" Max. Mounting Surface .375 Min. 9.53 +.0000 -.0003 Dia. +0.000 6.3424 -0.0076 1.20 R. Max. 30.6 90° Max. Slider .2497 .875±.031 22.2±0.79 2.00 Dia. 50.8 CCW CW 1.25 R. Max. 31.8 1.375 Dia. 34.93 .063 Lead Wires 5.50 Min. Length 1.59 140 +.000 -.002 +0.00 10.3 -0.05 .375 -32 NEF 9.53 Thread .375 9.53 .406 Locating Hole .129 .063 Dia. x Deep 3.28 1.59 Position as shown ± 5° .531 R. 13.5 No. of Sections Dim. "A" 1 Models 927 & 937 (Potentiometer Models 8146 & 7286) 2 3 "A" Max. CCW Slider Mounting Surface .813±.031 20.6±0.79 CW Lead Wires 5.50 Min. Length 140 +.0000 -.0005 Dia. +0.000 6.35 -0.013 .375 -32 NEF Thread 9.53 .250 +.000 -.010 +0.00 1.58 -0.25 .062 .313 7.94 75° Max. +.000 -.002 +0.00 10.3 -0.05 .406 +.005 -.000 Dia. +0.13 22.2 -0.00 3.55 90.2 4.11 104 4.68 119 .625 R. Max. 15.9 .875 Model 931 (Potentiometer Model A) No. of Sections Dim. "A" 3.55 1 90.2 4.11 2 104 Mounting Surface "A" Max. CCW CW .063 1.59 Slider Lead Wires 5.50 Min. Length 140 .063 1.59 .813±.031 20.6±0.79 .375 -32 NEF Thread 9.53 .125 Dia. 3.18 Locating Lug +.0000 .2497 -.0003 +0.000 6.3424 -0.0076 1.25 R. Max. 31.8 +.000 -.002 Dia. +0.00 10.3 -0.05 .406 .563 14.3 1.813 Dia. 46.05 No. of Sections Dim. "A" 4.63 1 118 6.83 2 174 8.73 3 222 .313 7.94 2-28 Model 920, 930, 940 Series OUTLINE DIMENSIONS (Inch/mm) Model 933 (Potentiometer Model C) Mounting Surface .813±.031 20.6±0.79 .063 "A" Max. CCW Slider Lead Wires 5.50 Min. Length 140 CW .375 -32 NEF Thread 9.53 .313 7.94 .063 1.59 .125 Dia. 3.18 Locating Lug 1.25 R. Max. 31.8 +.000 -.002 Dia. +0.00 10.3 -0.05 .406 1.59 2 .563 14.3 +.0000 .2497 -.0003 +0.000 6.3424 -0.0076 1.813 Dia. 46.05 No. of Sections Dim. "A" 3.70 1 95.8 5.05 2 129 6.09 3 155 Model 936 (Potentiometer Model 7283) "A" Max. .062 1.58 CCW CW Slider Mounting Surface .375±.031 9.52±0.79 .062 1.58 +.000 -.001 Dia. +0.00 15.9 -0.03 .625 105° Max. .625 R. Max. 15.9 .005 -.000 Dia. +0.13 22.2 -0.00 .875 Lead Wires 5.50 Min. Length 140 .781 Dia. Max. 19.8 .057 Min. 1.45 +.0000 -.0003 +0.000 3.170 -0.008 .1248 .922 23.4 Max. Clamp Dia. No. of Sections Dim. "A" 3.50 1 88.9 2 2-29 4.19 106 Model 920, 930, 940 Series MOTOR POT AND LOAD PERFORMANCE CALCULATIONS 1. To determine motor and load starting voltage: Vis = V s + e = Gear ratio Efficiency Jl = Load inertia (oz. in.-sec2) 6T1 eNTs 2. To determine slew velocity at terminal voltage: in.-sec2) Jm = Motor inertia (oz. Jt = Total inertia at motor shaft (oz. in.-sec2) Kt = Motor torque constant (oz. in./A) N = Gear ratio (N:1) Ra = Armature d-c resistance (ohms) Sni = No load motor speed at rated voltage (RPM) So = Slew velocity (RPM) t = Travel time (seconds) Tl = Load torque (oz. in.) Must include pot tm = Mechanical time constant (seconds) Ts = Motor stall torque at rated voltage (oz. in.) Vs = Motor no load starting voltage (Vdc) Vls = Start torque of motor and load Vdc) Vt = Terminal voltage (Vdc) θ = Degrees traveled So = SnlVt T1 Ts – eN 6TsN 3. To determine gear ratio: N= Snl 2So 1+ 1– 4TISo TsSnl 4. To determine degrees traveled: θ = 6So[t–tm(1 + 2.72-t/tm )] 5. To determine mechanical time constant: tm = RaJt 7X10-3 Kt2 Where: JI Jt = Jm + 2 N ORDERING INFORMATION 927 R5K T 5 L.25 G485 Model Series Resistance Value Gear Ratio Linearity Optional Non-Standard Tolerance NOTES CIRCUIT DIAGRAM Metric equivalents, based on 1 inch = 25.4mm are rounded to the same number of significant figures as in the original English units and are provided for general information only. (S) (CCW) INCH mm Tolerances unless otherwise specified: Linear = ± .01 inches (.25mm) Angular = ± 2 degrees (CW) 2-30 Model 920, 930, 940 Series