
156 Miscellaneous questions on Part I
VOLUME 1, CHAPTER 7
68.
With the aid of sketches, explain the difference between re-wirable,
cartridge and H.R.C. fuses.
69.
What is meant by fusing factor? A 30 A re-wirable fuse has a fusing
factor of 1.7. At what value of current will the fuse operate?
70.
For what purpose are H.R.C. fuses normally used and why?
71.
What is meant by discrimination? Why is it important to arrange for
discriminative protection?
72.
State three advantages of the circuit breaker over the fuse.
73.
With the aid of sketches explain the operation of a thermally
operated indirect tripping mechanism.
74.
What are the requirement ...