Post-Lab for DC Machines Locked Rotor Test Attach the vise grips provided in the lab kit to one of the machine shafts so that the shafts cannot rotate. Slowly adjust the voltage and current knobs of the supply until its output current is 1A. Record the supply voltage. Continue to increase the supply output until its output current is 2A. Once again, record the supply voltage. You will use this data to estimate the armature winding resistance R₂ of the machine. Set the output voltage and current of the power supply to zero. 1A = 1.2V 2A = 2.4V

Fig: 1