Why brake test is conducted on DC shunt motor?

In Direct Method, the DC machine is subjected to rated load and the entire output power is wasted. The ratio of output power to the input power gives the Efficiency of DC Machine. For a DC Generator the output power is wasted in resistor. Direct Method of testing when conducted on a motor is also known as Brake Test.

What is the purpose of brake test?

The purpose of this test is to measure the brake factors and thus determine the adhesion utilization of the front and rear axles over a range of braking rates between 0.15 and 0.8 .

Which parameter is measured using brake test on DC shunt motor?

In this method, the d.c. machine is loaded and output and input are measured to find the efficiency.

How do you test a DC shunt motor?

first test the field winding with a megohmmeter to check, that the winding has no short to the housing. Then check the current consumption of the field winding. If you can, start with a low voltage and rise it until you reach the nominal voltage. Look for the maximum current at the specification plate.

What is meant by DC shunt motor?

A DC shunt motor (also known as a shunt wound DC motor) is a type of self-excited DC motor where the field windings are shunted to or are connected in parallel to the armature winding of the motor. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage.

How do you use a brake tester?

Position the BrakeCheck unit on a level surface, such as the passenger side foot well. Once the vehicle is travelling at an appropriate test speed, check for traffic approaching from behind. If safe to do so, apply the footbrake as a controlled emergency stop, without skidding.

What are the advantages of Swinburne’s test?

Advantages of Swinburne’s Test

• This test is very convenient and economical as it is required very less power from supply to perform the test.
• Since constant losses are known, efficiency of Swinburne’s test can be pre-determined at any load.

What is the principle of DC shunt motor?

The working principle of a DC Shunt Motor is, whenever a DC motor is turned ON, then DC flows throughout stator as well as the rotor. This current flow will generate two fields namely pole as well as the armature.

Why Swinburne’s test is called No Load Test?

Due to armature reaction flux is distorted at full load and, as a result, the iron loss is increased. As the Swinburne’s test is performed at no load. Commutation on full load cannot be determined whether it is satisfactory or not and whether the temperature rise is within the specified limits or not.

What are the advantages of Sumpners test?

The only advantage of a Sumpner’s test is that no actual loading is required for determining the transformer parameters, which in other tests would have caused significant losses.

How to carry out a brake test of DC motor?

Brake Test of DC Motor is carried out as shown in figure below. A belt around the air cooled pulley has its end attached to the spring balance S1 and S2. Using belt tightening hand wheels H1 and H2, the load of motor is adjusted to its rated value.

What is the working principle of DC shunt motor?

Let us address DC shunt motor, working principle, operational features, speed control, characteristics, load test, and applications of DC shunt motor respectively. Definition: It is a type of motor that is used for constant load applications. Its winding is basically arranged in parallel with the armature winding.

What is direct method of testing when conducted on a motor?

Direct Method of testing when conducted on a motor is also known as Brake Test. Brake Test of DC Motor is carried out as shown in figure below. A belt around the air cooled pulley has its end attached to the spring balance S1 and S2. Using belt tightening hand wheels H1 and H2, the load of motor is adjusted to its rated value.

Do shunt DC motors degrade over time?

Since a shunt DC motor uses brushes to connect the power source to the spinning armature, they will naturally degrade over time. Most DC motors give a brush life (in hours) so that operators can record how long the brushes have been in use and when to replace them.