Question

An 800 rpm, 500 V, 120 A (armature current), series motor has a field resistance of 0,04 Ω and an armature resistance of 0.11 Ω. Determine the speed of the motor: 2.1 For a supply voltage of 550 V and a current of 60 A. (9) 2.2 For a torque of 50% of full-load, a supply voltage of 500 V and a diverter across the field of 0.08 Ω. (11) 2.3 With a resistance of 1 Ω in series with the armature, the torque being 75% of full load and a supply voltage of 500 V.

Answer #1

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...

A separately excited DC motor has the following parameters:
field resistance = 250 ?, armature resistance = 0.03 ?, terminal
voltage = 250 V and field voltage = 250 V. Initially the machine
runs at 1000 rpm with the terminal voltage = 250 V and armature
current = 120 A. a) find the speed of the motor if the load torque
dropped to 50% of its original value, b) find the speed of the
motor if the armature voltage is...

A 200 V DC, 1,800 RPM shunt connected motor has an armature
resistance of 0.4 ohm and a brush resistance of 0.4 ohm; brush
voltage drop of 6.0 V, independent of load. The resistance of the
shunt field is 230 ohm. The full load rated line current is 40 A.
When the motor is operated at no load the line current is 5 A and
the speed is 1750 RPM.
Calculate speed at rated load
Calculate speed at .3 rated...

The full-load armature current of a 5 hp, 150 V shunt dc motor
is 30 A. The field (shunt) resistance and the armature resistance
of the motor are ????F = 125 ? and ???????? = 0.15, respectively.
At a random speed of 1800 rpm magnetization curve of the motor has
measured and is shown in the table below. ????0 (V) armature
voltage 10 90 110 140 170 185 ???????? (A) field (shunt) current 0
0.82 1 1.2 1.7 2.88 Calculate...

A 230-V DC shunt motor has armature circuit resistance of 0.25 ?
and field circuit resistance of 115 ?. At
full load armature draws a current of 38 A and the speed is
measured at 1050 rpm. Find the developed
torque.
The field rheostat is now changed so that total field resistance is
144 ?. Find the speed under this condition.
Assume that the armature current does not change. Assuming the
rotational losses amount to 600 W, find the
efficiency...

Question 2
The full-load armature current of a 5 hp, 150 V shunt dc motor
is 30 A. The field (shunt) resistance and the armature resistance
of the motor are ????F=125 ? and ????????=0.15, respectively. At a
random speed of 1800 rpm magnetization curve of the motor has
measured and is shown in the table below.
EO(V) armature voltage
10
90
110
140
170
185
IF (A) field (shunt) current
0
0.82
1
1.2
1.7
2.88
Calculate the following:
a....

A 100 hp, 250 V, 1200 rpm DC shunt motor
with an armature resistance of 0.03 ? and a field
resistance of 41.67 ?. The motor has compensating
windings, so armature reactance can be ignored.
Mechanical and core losses may be ignored also. The
motor is driving a load with a line current of 126 A and
an initial speed of 1103 rpm. The magnetization curve is
shown in the following figure.
1. What is the motor speed if the...

B// A 4- pole 220 V, lap wound shunt D.C motor runs at 800 rpm
takes 35 A. The shunt field resistance is 110 Ω and armature
resistance is 0.4 Ω iron and friction losses is 800 W. Find. a-
Maximum efficiency. b- The resistance sections of starter connected
to this motor by using same armature resistance and voltage supply
from above. if maximum armature current is 50 A and the resistance
of first section is 1.95 Ω

A separate excited DC motor is running at 1000 rpm when the
armature voltage is 600 V. The motor has a field constant Kphi = 4
V.sec and the armature resistance of the motor is 0.8 Ohms.
i. Calculate the value of the resistance of the dynamic braking at
full load. The armature current should be limited to 200 % of the
rated value.
ii. If the motor operates in regenerative braking at a speed of
1200 rpm, calculate the...

A 5-kW, 220-V shunt motor has an armature resistance of 0.15 ?
and a field-circuit resistance of 100 ?. The motor delivers rated
output power at rated voltage when its armature current is 20 A.
When the motor is operating at rated voltage, the speed is observed
to be 1000 r/min when the machine is loaded such that the armature
current is 15 A. In order to protect both the motor and the dc
supply under starting conditions, an external...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 2 minutes ago

asked 2 minutes ago

asked 13 minutes ago

asked 15 minutes ago

asked 15 minutes ago

asked 29 minutes ago

asked 42 minutes ago

asked 43 minutes ago

asked 44 minutes ago

asked 49 minutes ago

asked 1 hour ago

asked 1 hour ago