Question

In: Physics

The constant-speed magnetization curve for a 25-kW, 250-V dc machine at a speed of 1200 r/min...

The constant-speed magnetization curve for a 25-kW, 250-V dc machine at a speed of 1200 r/min is shown in figure below. This machine is separately excited and has an armature resistance of 0.14 Ω. This machine is to be operated as a dc generator while driven from a synchronous motor at constant speed. a. What is the rated armature current of this machine? b. With the generator speed held at 1200 r/min and if the armature current is limited to its rated value, calculate the maximum power output of the generator and the corresponding armature voltage for constant field currents of (i) 1.0 A, (ii) 2.0 A and (iii) 2.5 A. c. Repeat part (b) if the speed of the synchronous generator is reduced to 900 r/min.

Solutions

Expert Solution


Related Solutions

‏The speed of a 11 KW, 150 V, 1300 rev/min separately excited DC motor is controlled...
‏The speed of a 11 KW, 150 V, 1300 rev/min separately excited DC motor is controlled by a ‏single-phase fully-controlled thyristor converter. The rated motor current is 25 A, and the ‏armature resistance is Ra = 0.5 Ohm. The ac supply is 160 V. The motor voltage constant KE = ‏0.182 V/rev/min. Assume that sufficient inductance is present in the armature circuit to make ‏the armature current continuous and ripple free. ‏For a firing angle of alpha = 20 degree...
A 1200 kW, 550 V DC generator has a terminal voltage of 500 V at rated...
A 1200 kW, 550 V DC generator has a terminal voltage of 500 V at rated current. It is being driven at a speed of 400 rpm. The armature resistance is 0.0009 Ω. a. Determine the armature voltage. b. Determine the developed torque. c. Determine the armature copper loss.
A 100 hp, 220 V, 1200 rpm DC shunt motor with an armature resistance of 0.05...
A 100 hp, 220 V, 1200 rpm DC shunt motor with an armature resistance of 0.05 ? and a field resistance of 50 ?. The motor has compensating windings, so armature reactance can be ignored. Mechanical and core losses may be ignored also. The motor is driving a drilling machine, TL ? (1/n). The motor is driving a load with a line current of 120 A and an initial speed of 1200 rpm. Assume Linear Magnetization curve i. What is...
A 5-kW, 250-V shunt motor has an armature resistance of 0.1 ? and a field-circuit resistance...
A 5-kW, 250-V shunt motor has an armature resistance of 0.1 ? and a field-circuit resistance of 80 ?. When the motor is operating at rated voltage, the speed is observed to be 1200 r/min when the machine is loaded such that the armature current is 30 A. In order to protect both the motor and the dc supply under starting conditions, an external resistance will be connected in series with the armature winding (with the field winding remaining directly...
A 230 V, 250 rpm, 100 A separately excited dc motor has an armature resistance of...
A 230 V, 250 rpm, 100 A separately excited dc motor has an armature resistance of 0.5 Ω. The motor is connected to 230 V dc supply and rated dc voltage is applied the field winding. It is driving a load whose torque-speed characteristic is given by TL = 500 − 10ω where ω is the speed in rad/sec and TL is the load torque in N-m. Find (a) the steady state speed at which the motor will drive the...
Problem 5) A long shunt 600 V, 1200-rpm DC motor has a series field winding resistance...
Problem 5) A long shunt 600 V, 1200-rpm DC motor has a series field winding resistance of 0.05 Ω, a shunt field winding resistance of 200 Ω, and an armature resistance of 0.1 Ω. The machine is connected to 600 V DC source. The rotational loss is 3.2 kW. If the machine draws a 100 A from the supply, calculate a. Back EMF b. Determine the machine’s converted power (or developed power) and its efficiency. c. Determine the speed regulation...
A 240 V DC shunt motor draws 40 A while driving a constant torque load. The...
A 240 V DC shunt motor draws 40 A while driving a constant torque load. The armature resistance is Ra = 0.2 Ω, the field resistance is Rf = 240 Ω and machine constant is Ka = 120. The part of magnetization characteristic (field flux versus field current) related to the question is: If (A) :      0.70 0.80 0.86 0.90 1.00 1.10 1.20 1.30 1.40 ϕ (mWb) : 5.80 6.30 6.59 6.70 7.20 7.60 7.96 8.20 8.45 The constant rotational...
A 25 kg suitcase is being pulled with constant speed by a handle that is at...
A 25 kg suitcase is being pulled with constant speed by a handle that is at an angle of 26 ∘ above the horizontal. If the normal force exerted on the suitcase is 170 N , what is the force F applied to the handle?
Consider the Potential V(r) =Vo (c/r) exp (-r/c) (where c is a constant) and a deutron...
Consider the Potential V(r) =Vo (c/r) exp (-r/c) (where c is a constant) and a deutron of reduced mass m moving in this potential . (a) Using a trial wave function R(r) = exp (- d *r / c) (d is constant ) find the ground state energy if Vo= 1.35 (b) If one bound state energy is -2.2 find Vo
A long, straight wire carrying a current of 3.00 A moves with a constant speed v...
A long, straight wire carrying a current of 3.00 A moves with a constant speed v to the right. A 5-turn circular coil of diameter 1.25 cm, and resistance of 3.25 µΩ, lies stationary in the same plane as the straight wire. At some initial time, the wire is at a distance d = 19.5 cm from the center of the coil. 4.55 s later, the wire is at a distance 2d from the center of the coil. What is...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT