DC SHUNT MOTOR STARTER DOWNLOAD

DC SHUNT MOTOR STARTER DOWNLOAD

DC SHUNT MOTOR STARTER DOWNLOAD!

Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor's armature winding and restricts the current to an acceptable level. FIGURE 1: Equivalent circuit of a DC shunt motor. One way to limit the inrush current is to reduce the voltage that is applied to the motor and then bring it up. Abstract. This paper is presented as an overview of starter designing and characteristics of DC shunt motor. The aim is to introduce in brief the.


DC SHUNT MOTOR STARTER DOWNLOAD

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DC SHUNT MOTOR STARTER DOWNLOAD


To find the answer to this question let us look into the working of No Voltage Coil.

DC SHUNT MOTOR STARTER DOWNLOAD

So when field current flows, dc shunt motor starter NVC is magnetized. Now when the handle is in the 'RUN' position, a soft iron piece is connected to the handle and gets attracted by the magnetic force produced by NVC, because of flow of current through it.

3 Point Starter | Working Principle and Construction of Three Point Starter

The NVC is designed in such a way that it holds the handle in 'RUN' position against the force of the spring as long as supply is dc shunt motor starter to the motor.

Now when there is any kind of supply failure, the current flow through NVC is affected and it immediately loses its magnetic property and is unable dc shunt motor starter keep the soft iron piece on the handle, attracted.

At this point under the action of the spring force, the handle comes back to OFF position, opening the circuit and thus switching off the motor. So due to the combination of NVC and the spring, the starter handle always comes back to OFF position whenever there is any supply problem.

3 Point Starter | Working Principle and Construction of Three Point Starter

Thus it also acts as a protective device safeguarding the motor from any kind of abnormality. Because Ra is designed to be small, applying full voltage to it could result in current several dc shunt motor starter the rated current of the machine.

Such a high current could cause serious commutation problems because the commutator must reverse the current in a coil during the time the brushes are shorting out the coil. If the current is too high, it will not reverse during the commutation interval and arcing will occur at the brushes.

In general, the motor starting current should be limited to twice the rated full-load current to prevent excessive commutator arcing.

Starting methods of a DC motor

Equivalent circuit of a DC shunt motor. One way to limit the inrush current is to reduce the voltage that is applied to the motor and then bring it up slowly to rated voltage.

Of course, that requires a variable-voltage DC supply. Although such a supply is frequently available in the laboratory, it is usually not in the workplace. Thus, we must limit the dc shunt motor starter by other means.

Starting methods of a DC motor |

In particular, we can change the voltage applied to the motor by placing the resistance in series with it, as shown in Figure 1.

By placing a large resistance in the circuit dc shunt motor starter starting and reducing it in steps as the speed increases, the motor may be started quickly without excessive armature current.

Dc shunt motor starter may cause severe damage. To avoid this, a suitable DC motor starter must be used. Very small dc motors, however, may be started directly by connecting them to the supply with the help of a contactor or a switch.

It does not result in any harm because they gather speed quickly due to small rotor inertia.

DC Motor Starters and Their Circuit Diagram | Electrical Academia

In this case, the large starting current will die down quickly because of the fast rise in the back emf. DC motor starters To avoid the above dangers while starting a DC motor, it is necessary to limit the starting current.

So, a DC motor is started by using a starter.