Answer:
a) 2.2 KW
b) 1899.616 W
c) 300.383 W
d) $54.208
Step-by-step explanation:
Given:
- current drawn by motor i = 20 Amps
- Voltage supplied V = 110 V
- speed of shaft N = 2000 rpm
- Torque of the shaft T = 9.07 N-m
Find:
(a) the magnitude of the power input in W
(b) the output power, in W
(c) the magnitude and direction of any heat transfer that must be present, in W
(d) the cost of 224 hours of operation if electricity is valued at $0.11 per kW-hr.
Solution:
(a)
W_in = P = i * V
W_in = (20 Amps)*(110 V) = 2200 W
(b)
W_out = T*w
W_out = (2*pi*N*T) / 60 = (2*pi*2000*9.07) / 60
W_out = 1899.616 W
(c)
Q_loss = W_in - W_out
Q_loss = 2200 - 1899.616
Q_loss = 300.383 W
(d)
Cost = Rate * W_in*time
Cost = ($ 0.11 / KW-h) * (2.2 KW)*(224 h)
Cost = $54.208