Question 9: Sources of Heat:
Heat generate due to ohmic energy losses in the winding. Winding is made up of wire and have resistance to it. so when current is passed, I^{2}R power is being dissipated as heat.
In DC motor there is shunt field winding, Amrature Windings, Iron losses ( that are being classified as Hysteresis Loss and Eddy current losses) and fiction in ball bearing are the sources of Heat.
Question 10: YES, When a cooling fan is mounted on the shaft it increases the load of the motor because the fan drag the air to the motor, this air resistance and the weight of fan adds to the load of the motor.
Question 11: Losses are undesirable because:
1) They waste power, can cause excessive heating in the motor, can accelerate wear-out and cause premature failure of the motor, etc.
2) the problems above increase the need for maintenance, thus increasing lifetime cost.
Question 12: How much torque does this motor have?
Torque is not only the main characteristic for the motor to know. a person should also know the Efficiency and power consumption. so the question should be reframed as: What is the efficiency and power consumption of this motor. This would give major idea of power calculation. Please post Full previous questions to able to answer the questions and Recommendation exactly.
QUESTIONS Question-3: Draw "speed vs. torque" curve using data in Table-1. The completed graph represents the speed vs. torque characteristics of a typical DC shunt-wound motor. Terax Qu...
QUESTION 1 A) (10 marks) A 10 kW, 250 V DC self-excited shunt generator, with an armature resistance of 0.1 ohm, is delivering 80 % of rated power to the mains at rated voltage when being run at 1000 r.p.m. (revolutions per minute). The field circuit resistance is 220 ohms. The brush contact drop is 0.5 V and rotational (mechanical) losses are 750 W Calculate The induced voltage The electromagnetic torque developed The shaft torque The overall efficiency B) (15...
A 220 V DC shunt motor has an armature resistance, Re-0.1 S2, a field resistance, Ry=100 12, and negligible rotational losses. Under certain load conditions, the shunt motor runs at 1600 rpm while drawing a total current, I = 100 A. Determine: a. the output power of the motor; b. the output torque in N-m; and, c. the efficiency Without making any changes to the applied voltage or the field, the motor operates with a new M mechanical load that...
Hello i need help with question #4 , please show your work ty! /3 TABLE 1 VOLTS 115 0.6532 EC613-31BRAKE. ECG13-43 TABLE 2 BASE UNIT 23 140 53 3 TABLE 3a sov( TABLE 3b 5A IIS 0.3 38 FIGURE 1 ASSIGNMENT Draw a cirauit diagram for the DC Motor used in this experiment. 1 What are the losses in a motor? Which ol the losses are constent and which are variable? (2) Caleulate the following trom the deta in Table...
need the answer for the question no. 1 ENGR 113 Homework DC Motor Objectives Plot the Torque-Speed curve for a given DC motor given the stall torque and no load speed values Calculate the rotational power for a DC motor given the stall torque and no load speed values Plot the rotational power on a Torque-Speed curve to see the relationship between torque, speed, and power Calculate the maximum efficiency of a DC motor. Calculate the operating point for a...
Show all working 1. A 4 pole, 220 V, 10 H.P, d.c. shunt motor is rotating at a speed of 320 rpm. Then the developed useful torque is 2. A 4 pole, lap wound d.c. motor drawing an armature current of 20 A has 360 conductors. If the flux per pole is 0.015 Wb then the gross torque developed by the armature of motor is 3. A 220 V, d.c. motor draws an armature current of 20 A. Its armature...
1. A 300 V compound motor has armature resistance 0.18 Ω, series field resistance 0.3 Ω and shunt field resistance 100 Ω. The rotational losses are 200 W. On full load the line current is 25 A and the motor runs at 1800 rpm. Determine: (i) the developed mechanical power (ii) the output power (iii) the output torque (iv) the efficiency at full load 2. A 120 V series motor has 0.2 Ω field resistance. On full load, the line...
MESB443, Semester 1 2018/19 QUESTION 3 [10 marks) A 200V DC shunt motor develops a rated output power of Shp at 1000rpm, drawing 25A. Having Ra=0.50 and RF = 10092, find: a) The total rotational losses of the motor at rated conditions [4 marks] b) The no-load speed of the motor at 2001. [6 marks] Answer:
Question (3) Speed Control [10 Marks A 50 hp, 220 V, 1500 rpm DC shunt motor with an armature resistance of 0.04 Q and a field resistance of 50 Q. The motor has compensating windings, so armature reactance can be ignored. Mechanical and core losses may be ignored also. The moter is driving a load toque that is proportional with speed, Ti a (n). The motor is driving a load with a line current of 80 A and an initial...
14. The following details are known about a 200 hp, 500 V, 435 rpm de shunt motor: full-load current is 330 A, insulation class is H, weight is 3400 kg, external diameter of the frame is 915 mm and length of the frame is 1260 mm. If the motor is running at full-load, calculate: a. the total losses and efficiency. b, the approximate shunt field exciting current if the shunt field causes 15% of the total losses. the value of...
5.2. (15 pt.) A shunt DC motor has the following characteristics Prated 30 hp, Vt = 240 V; nated 1200 rpm Ra-0.19 Ω; Rs 0.02 2; Rotational losses at full load 3550 W rated= 110 A NF 2700 tums per pole NSE 12 turns per pole Radj 100 to 400 Ω 320 Speed = 1200 r/min 240 き 200 180 3 160 140 120 100 0 0. 0.2 0.3 04 0.5 0.6 0.7 0.8 0.9 1.0 1. 2 13 1.4...