A long shunt dynamo running at 1000 rpm supplies 33 kW at a terminal v...
To find the torque exerted by the prime mover in a long shunt dynamo, we can use the formula:
\[T = \frac{P_{\text{output}}}{\omega}\]
Where:
T = Torque exerted by the prime mover (in N-m)
\(P_{\text{output}}\) = Output power of the dynamo (in watts)
\(\omega\) = Angular velocity (in radians/second)
Let's calculate the output power first:
\[P_{\text{output}} = P_{\text{terminal}} - P_{\text{losses}}\]
Where:
\(P_{\text{terminal}}\) = Terminal power (in watts)
\(P_{\text{losses}}\) = Power losses in the dynamo (in watts)
The terminal power can be calculated using the formula:
\[P_{\text{terminal}} = V_{\text{terminal}} \times I_{\text{terminal}}\]
Where:
\(V_{\text{terminal}}\) = Terminal voltage (in volts)
\(I_{\text{terminal}}\) = Terminal current (in amperes)
To find the terminal current, we can use Ohm's law:
\[I_{\text{terminal}} = \frac{V_{\text{terminal}}}{R_{\text{total}}}\]
Where:
\(R_{\text{total}}\) = Total resistance of the circuit (in ohms)
The total resistance can be calculated as:
\[R_{\text{total}} = R_{\text{armature}} + R_{\text{shunt field}} + R_{\text{series field}}\]
Now, let's calculate the power losses:
\[P_{\text{losses}} = I_{\text{terminal}}^2 \times (R_{\text{armature}} + R_{\text{shunt field}} + R_{\text{series field}})\]
Finally, we can calculate the torque exerted by the prime mover:
\[T = \frac{P_{\text{output}}}{\omega}\]
Given values:
\(P_{\text{output}} = 33 \, \text{kW} = 33000 \, \text{W}\)
\(\omega = 1000 \, \text{rpm} = \frac{1000}{60} \, \text{rad/s}\)
\(V_{\text{terminal}} = 220 \, \text{V}\)
\(R_{\text{armature}} = 0.05 \, \Omega\)
\(R_{\text{shunt field}} = 10.0 \, \Omega\)
\(R_{\text{series field}} = 0.06 \, \Omega\)
Let's substitute the values and calculate the torque:
\[I_{\text{terminal}} = \frac{V_{\text{terminal}}}{R_{\text{total}}} = \frac{220}{0.05 + 10.0 + 0.06} \, \text{A}\]
\[P_{\text{losses}} = I_{\text{terminal}}^2 \times (R_{\text{armature}} + R_{\text{shunt field}} + R_{\text{series field