What is Hopkinson test in DC machine?

Hopkinson’s Test is another useful method of testing the efficiency of a DC machine. It is a full load test and it requires two identical machines which are coupled to each other.

What is the purpose of Hopkinson test?

Definition: A full load test which is used to test the efficiency of a DC machine is known as Hopkinson’s test. An alternate name of this test is back to back, heat run, and regenerative test. This test uses two machines which are connected electrically and mechanically with each other.

How does Hopkinson test is done?

Hopkinson’s Test is also known as Regenerative Test, Back to Back and Heat Run Test. In Hopkinson Test, two identical shunt machines are required which are coupled both mechanically and electrically in parallel. One is acting as a motor and another one as a generator.

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.

Which applications require high starting torque?

Which of the following application requires high starting torque?

• Lathe machine.
• Centrifugal pump.
• Locomotive.
• Air blower.

How voltage is built in DC shunt generator?

As there is small voltage is there across the terminals of DC Shunt Generator and Switch S is closed, therefore a small current will start flowing through the field circuit of DC Shunt Generator which in turn will produce magnetic flux and if the produced magnetic flux adds the residual magnetic flux then net flux will …

What is the use of 3 point starter?

A three-point starter is an electrical device, used for starting as well as maintaining the DC shunt motor speed. The connection of resistance in this circuit is in series which decreases the initial high current and guards the equipment against any electrical failures.

What is the use of 4 Point starter?

Four-point starter: The four-point starter works as a current controlling device in the deficiency of back EMF while it starts running off the DC motor. A four-point starter also works as a protecting device.

What is the use of Swinburne test?

The Swinburne test is an indirect method for determining the efficiency of DC motors. It works by finding the no-load losses experimentally and then estimating additional losses from the rated motor data. From this information, the efficiency can be determined at any applied load.

Why is a DC machine test done?

To perform its electrical characteristics, several tests are conducted for testing of a dc machine (Generator or Motor). Testing of machines is used for finding Losses, Temperature rise and Efficiency. When losses are decrease, The efficiency is increase and it is vice-versa.

Which DC motor has maximum self loading property?

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.

How are shunt machines used in Hopkinson test?

In Hopkinson Test, two identical shunt machines are required which are coupled both mechanically and electrically in parallel. One is acting as a motor and another one as a generator. The input to the motor is given by the supply mains.

What kind of test is the Hopkinson test?

Hopkinson Test. Hopkinson’s Test is another useful method of testing the efficiency of a DC machine. It is a full load test and it requires two identical machines which are coupled to each other.

Which is the best DC shunt machine to use?

This test is mainly applicable for conducting a No-load test. DC shunt machine is the best option for conducting No-test. During the No-load test, the current directly appears across the field winding of the DC series machine which results in the burning of winding.

Can a Hopkinson’s test be built with a generator?

The circuit diagram of the Hopkinson’s test is shown below. The circuit can be built with a motor as well as a generator together with a switch. Whenever the motor is started then the shunt filed resistance of this motor can be adjusted so that it runs at its rated speed.