Answer Posted / abhi
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. One of these two machines is operated as a generator to supply the mechanical power to the motor and the other is operated as a motor to drive the generator. For this process of back to back driving the motor and the generator, Hopkinson's test is also called back-to-back test or regenerative test.
If there are no losses in the machine, then no external power supply would have needed. But due to the drop in the generator output voltage we need an extra voltage source to supply the proper input voltage to the motor. Hence, the power drawn from the external supply is therefore used to overcome the internal losses of the motor-generator set.
| Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
what material is used in capaciter
What are the functions of temperature scanner in power transformer?
what is the difference between unarmoured & Flexible cable? How to identified?
what is upper impedance and lower impedance of a distance relay
is that a problem if i connect a single phase load to a secondry delta connected transformer but i get a neutral from other transformer i the system?
What is voltage divider rule?
How to calculate the current of Highpressure Mercury Vapour Lamp?what is the basis?whether we have to consider power factor or not?
What is the function of electron gun assembly used in crt?
Why negative feedback is preferred in the control system?
Hoe do calculate the Cable size for Amps rating ?
Whata are the types of Cables?
what is the meaning of osr in transformer.
What is the current carrying capacity of 0SWG,3SWG,10 & 12 SWG solid bare overhead copper conductors?
derive DC RMS value for half wave rectifier?
Why the cores of large transformers build up of circular cross section?
