What is the working principle of a DC shunt motor?

Answer 1

To ensure that the Lathe machine's motor working properly, DC motor starter is added in which it used to protect motor against damage from: • short-circuit, • long term overload, • excessive starting current, and yet to made the operating speed of motor easily to be control by operator. During starting, the motor is not turning, hence there is no internal voltage .The internal resistance is very low and thus the current flow through is very high. This condition may cause damage to the motor Hence, a staring resistor is added in which connect in series with the armature to limit the current flow until the internal voltage of motor is increasing to do the limiting. In order to prevent losses as the speed of the motor is build up; the starting resistor should be removed

Answer 2

A DC shunt motor usually runs on a fixed-voltage supply.

1. The field current sets the field intensity, and the armature voltage is proportional to the field intensity and the armature speed.

2. The armature current is the difference between the supply voltage and the armature voltage, divided by the armature resistance.

3. The torque is proportional to the field intensity and the armature current.

That's about all you need to know.

In an ideal motor the armature has zero resistance and the armature rotates at a constant speed determined by the supply voltage and the field current (from 1.). If the field current is increased, the speed falls.

The armature current is determined by the load torque (from 3.).

In a non-ideal motor there is a finite armature resistance, an increased load torque causes more current to be drawn, and the armature voltage has to fall so that the current can flow, so the speed falls.

Answer 3

Some Uses of DC Shunt motors are as below:

Reciprocating pump

Centrifugal pump

Lathe

Blower and Fan

Machine tools

Constant speed line shaft, etc...

Answer 4

D.C. motors are categorised according to the way in which the field winding is connected in relation to the armature winding. The term 'shunt' is an archaic word for 'parallel', so a d.c. 'shunt motor' is one in which the field winding is connected in parallel with its armature winding. Another category is the d.c. 'series motor', in which the field winding is connected in series with the armature winding. Yet another category is the d.c. 'compound motor', in which there are two field windings; one in parallel, and the other in series, with the armature winding. Each of these connections gives a d.c. motor a different operating characteristic, making them suitable for different types of load.

Answer 5

'Shunt' is an archaic term for 'parallel'. So a 'shunt d.c. motor' is one whose field winding is connected in parallel with the supply voltage.

Answer 6

Dc shunt implies field windings in parallel to armature,dc series means field windings in series with armature windings.