Calculate the field winding temperature for a machine with a field resistance of 1.35 ohms hot,...
A series of excitation DC motors have an armature winding resistance of 0.3 ohms, a field winding resistance of 0.1 ohms, a rotational speed of 650 rpm, a back emf is 120 V, and an armature current of 78 A. If the torque is constant, 0.6 ohms is connected in series with the armature, what is the speed of the motor after it is stabilized?
10. A primitive de machine has a field winding of resistance 20052 and inductance 40H. The armature winding has a resistance 0.152 and inductance 0.1H and connected to a load resistance of 52 and inductance 5H, With a steady field current of 1A, the armature on open circuit is 200V. Determine the expression of the armature current after a voltage sudden connection of the field to a 200V supply. 10. A primitive de machine has a field winding of resistance...
Q: The field winding of a d.c. motor is connected directly across a 440 V supply. When the winding is at the room temperature of 17 °C, the current is 2.3 A. After the machine has been running for some hours, the current has fallen to 1.9 A, the voltage rem aining unaltered. Calculate the average temperature throughout the winding, assuming the temperature coefficient of resistance of copper to be 0.004 26/°C at 0 °C.
a coil has a resistance of 18 ohms when its mean temperature is 20C and of 20 ohms when its mean temperature is 50C. find the mean temperature rise when its resistance is 21 ohms and the surrounding temperature is 15C.
If a certain machine makes electrical resistors that have an average resistance of 40 ohms and a standard deviation of 2 ohms, what is the probability that a random sample of 32 of these resistors has an average resistance of at most 39.5 ohms? Write the result with up to 4 decimals.
A copper wire has a resistance of 9.00 ohms at 33.0 degrees. Determine the resistance (in ohm) at 433 degrees celsius. The temperature coefficient of resistivity for copper wire is 3.90*10^-3 degrees celsius to the negative one power. (Assume that the temperarure coefficient of resistivity was measured using the reference temperature 20 degrees celsius.)
A length of AWG #12 copper wire has a resistance of 0.020 Ohms at 20 °C. Calculate the temperature for which the resistance is 0.023 Ohms.
The tungsten filament of an incandescent lamp has a resistance of 200 Ohms at room temperature. A) What would the resistance be at an operating temperature of 1600 C? B) Assuming it is plugged into a 120-V outlet, what is its power output when just starting up? C) By how much does its power output change from the room temperature value when it is at its operating temperature?
it is found that the resistance of a coil of wire increases from 40 ohms at 15C to 50 ohms at 60C. calculate the resistance temperature coefficient at 0C of the conductor material?
03 (5pts): A 250-V shunt motor has an armature resistance of 0.25 Ohms and a field resistance of 125 Ohms. At no-load the motor takes a line current of 5.0 A while running at 1200 rpm. If the line current at full-load is 62.0 A, what is the full-load speed? When the line current is 62 A, the field resistance is increased to 200 Ohms, what is the new speed of the motor?