150 damentals Industri I d d s ia l l Rob bo tics s Fu un Copyright Goodheart-Willcox Co., Inc. Copyright Goodheart-Willcox Co., Inc. Activity 6 -5 DC Stepping Motors Objectives DC stepping motors represent a unique electromechanical rotary actuator that is used in robotic systems. These motors are designed to change electrical pulses into rotary motion. The amount of rotary movement or angular displacement produced by each pulse is repeated precisely for each succeeding pulse. The resulting rotation of these motors may be used to locate or position worktables or fi xtures accurately for automatic machining operations. Very precise degrees of fi accuracy can be achieved with these devices. In this activity, you will construct a simple test circuit for a dc stepping motor. You will be able to produce very accurate shaft movements by using different switching step combinations. Both the four-step and eight-step switching com- binations will be tested. Through this activity, you will be able to observe the b physical operation and test the accuracy of motor shaft rotation. The switching operation of this activity is achieved automatically by logic devices in actual oper- ating circuits. Precise switching operations obviously improve the accuracy of this circuit. Equipment and Materials • DC stepping motor—Superior Electric Type M061-FD02 or equivalent. • SPST switches (4). • Resistor—50 Ω, 20 W. • Resistor—1000 Ω, 1/2 W. • DC power supply—0–25V, 1 A. • Diodes—1N4004 (4). Safety Use protective eyewear during this activity. Procedure: 1. Construct the stepping motor test circuit as shown in the next fi gure. fi 2. The physical movement of the stepping motor shaft is small and rather diffi to observe. By attaching a simple indicating device, such as a small ficult wire or paper pointer, to the motor shaft the mechanical rotation can be readily observed. 3. The switching sequence in the full-step mode will produce 1.8 steps for each switching combination.