Q9. With reference to reverse power protection for A.C. generators operating in parallel:
(a) explain why traditional reverse power relays, operating on mechanical principles, have been replaced by electronic digital microprocessor types; (2)
(b) describe, with the aid of a sketch, a generator reverse power protection circuit that uses an electronic phase sensitive detector. (8)
Q9. With reference to voltage variation profiles caused by load changes imposed on alternating current generators when starting large motors online:
(a) sketch a voltage dip, showing an acceptable recovery time; (2)
(b) state FOUR salient factors that cause the variation in part (a); (4)
(c) outline FOUR salient factors that assist recovery from the deviation shown in part (a). (4)
Q11. With reference to large electrical transformers on board ships:
(a) state where these transformers may be used; (1)
(b) state a typical efficiency range for a transformer; (1)
(c) state the regulations pertaining to transformers; (3)
(d) state the protective devices that are fitted; (2)
(e) describe the maintenance requirements. (3)
Username or email address *Required
Password *Required
Note: Entering wrong username in the login form will ban your IP address immediately. Entering wrong password multiple times will also ban your IP address temporarily.
Log in
Lost your password? Remember me
No account yet?
