Is armature current and field current same?

Is armature current and field current same?

In shunt generator armature current will be sum of Field current and Load current. In shunt Motor the load current is equal to the sum of field current. and armature In shunt motor the load current is equal to the armature current.

What is armature current and field current?

In the armature, an electromotive force is created by the relative motion of the armature and the field. When the machine or motor is used as a motor, this EMF opposes the armature current, and the armature converts electrical power to mechanical power in the form of torque, and transfers it via the shaft.

Can you explain why there is an armature voltage even when the field current is zero?

However, even when the field current is zero, some amount of emf is generated (represented by OA in the figure below). This initially induced emf is due to the fact that there exists some residual magnetism in the field poles. Due to the residual magnetism, a small initial emf is induced in the armature.

What kind of relationship exists between the armature voltage EA and the DC motor speed N?

Linear Relationship
Linear Relationship Between the Motor Speed and the Armature Voltage. Since the relationship between voltage E, and speed n is linear, a dc motor can be considered to be a linear voltage-to-speed converter as shown in Figure 2-10.

Which DC motor has maximum self loading property?

Series motor. Shunt motor. Cumulatively compounded motor.

What is the formula for armature current?

For initial operating point: IL1 = 20 A, ra = 0.5 Ω and supply voltage V = 220 V. Field current If1 = 220/220 A = 1 A Armature current Ia1 = 20 A – 1 A = 19 A Now we write down the expressions for the torque and back emf corresponding to the initial condition.

What is a field current?

: the current supplied to the field windings of a generator or motor to establish the magnetic field for its operation.

How the voltage is build up when field current is zero?

When 1 amp current is flowing through the field some flux would build up. Now, if we reduce the field current to zero then due to residual magnetism property of the field core it would hold some flux which leads to slightly increase the voltage above 6 Volt. Hence in both cases terminal voltage will be same.

What are the parts of DC motor?

What are DC Motor Parts and how they work?

• Stator. A stator is one of the DC motor parts that is, as the name suggests, a static unit containing the field windings.
• Rotor.
• Yoke.
• Poles.
• Field Windings.
• Armature Windings.
• DC Motor Commutator.
• Brushes.

What is the relation between armature voltage and speed?

the armature voltage has a control over the torque developed in the armature. for example, if load increases, speed decreases, back emf decreases (emf equation), then the factor (v-EB) increases, so Ia=(v-Eb)/Ra increases. if Ia increases, torque increases(torque equation).

What is self loading property of motor?

4. Which DC motor has got maximum self-loading property? Explanation: A differentially compound DC motor, flux reduces so sharply at small increase in load at higher values of load. It is advisable that motor should not be used beyond some load value, as it may damage itself by self-loading.

How are current and torque related in an armature loop?

The armature voltage equation and torque equation, together with the linear relationship for flux, can be substituted into the series armature loop voltage equation to obtain and understanding of the relationship between speed, current and torque at as a function of terminal voltage.

What is the relationship between armature voltage and IA?

The input voltage being constant, the input current has to increase, ie, Ia. . In the above equation, all are constants except Eb. The motor adjusts its speed such that it draws more Ia. According to equation two, Eb has to decrease to draw more Ia and hence the motor speed decreases.

How is armature, field and terminal currents equal?

In a series connected machine, the armature, field and terminal currents are equal: As the armature current of a machine is typically much higher than the field current of a separately excited machine, the field winding in a series machine has fewer turns than the field winding in a separately excited machine.

How to calculate the armature voltage at 1200 rpm?

The armature winding resistance R A = 0.2 Ω, and the armature terminal voltage V T = 130 V. Friction and windage losses can be neglected. The motor drives a load at 1200 rpm. Calculate the armature voltage at 1200 rpm if the field resistance R F = 60 Ω