NAME: ____________________ LAB Section: __________________ TA: ___________________ Quiz 2.A (Practice) The questions refer to the robot DC motor sketched here, and the DC motor equations shown. VDC = RM I DC + LM
VEMF = kω
T=J
dI DC
+ VEMF
dt
dω
+ Bω + Tload
dt
T = kI DC
1. Frequency of the encoder pulses is fenc = 384 Hz. What is the wheel speed in revolutions per second [rps]? 2. The DC motor constant is k = 1 Nm/A. Resistance of the armature winding is RM = 2 Ω. The DC motor is supplied from a bench dc power supply, which has been set to 6 V and 1 A limits. 2.1. When the wheel is locked (speed is zero), find the following in steady state: (a) Motor DC voltage VDC = (b) Motor DC current IDC = (c) Generated mechanical torque, T = 2.2. When the wheel is allowed to rotate freely, IDC = 0.1 A. Find the following in steady state: (a) Motor DC voltage, VDC = (b) Wheel speed in radians per second, ω = Fall 2011 Electronics Design Laboratory