Efficiency and Testing of DC Machines

If the field current and armature current are reversed, then

Swineburne’s test is applicable to those machines in which flux is practically _____

Hopkinson’s test is also called regenerative test due to

In the Hopkinson’s test on two DC machines. Machine A has field current of 1.4A and B has field current of 1.3A. Which machine acts as generator?

In the hopkinson’s test on two DC machines. Machine A has field current of 1.4A and B has field current of 1.3A. Which machine acts as motor?

The main concern before doing hopkinson’s test for finding efficiency is

A dc motor is connected in the short-shunt configuration, but the series and the shunt windings get interchanged by mistake and the motor is connected to the rated voltage,

The efficiency in the swineburne’s test can be found.

The quantities needed to complete retardation test are/is

The most appropriate relation to find efficiency of the generator

Mark the possible causes of overheating of commutator in a DC machine

Similarity between Hopkinonson’s and field’s test is that

The possible assumption is/are made while doing swineburne’s test
(i) mechanical loss constant
(ii) Armature reaction neglected
(iii) Increases in flux

______ test is used for determining the efficiency of a traction motor

Retardation test on DC shunt motor is used for finding _______