MGVCL Exam Paper (30-07-2021 Shift 2)
The miniature circuit breaker (MCB) with Class D trip characteristics trips instantaneously when the current flowing through it reaches ____ the rated current.
Class B trip curve : The MCB with class B trip characteristics trips instantaneously when the current flowing through it reaches between 3 to 5 times rated current. These MCBs are suitable for cable protection.
Class C trip curve: MCB with class C trip characteristics trips instantaneously when the current flowing through it reaches between 5 to 10 times the rated current. Suitable Domestic and residential applications and electromagnetic starting loads with medium starting currents.
Class D trip curve: MCB with class D trip characteristics trips instantaneously when the current flowing through it reaches between Above 10 (excluding 10) to 20 times the rated current. Suitable for inductive and motor loads with high starting currents.
Class K trip curve: MCB with class K trip characteristics trips instantaneously when the current flowing through it reaches between 8 to 12 times the rated current. Suitable for inductive and motor loads with high inrush currents.
When different types of consumers are charged at different uniform per unit rates, it is said to be Flat Rate Tariff. In this type, the consumers are grouped into different classes. Each class is charged at different uniform rate.
The main function of an interposing CT is to balance the currents supplied to the relay where there would be an imbalance due to the ratios of the main CTs. Interposing CTs are equipment with a ratio that can be selected by the user to achieve the balance required. An interposing CT is installed between the secondary winding of the main CT and relay.
EXAMIANS