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IEC 61992-2-2014 pdf free download

IEC 61992-2-2014 pdf free download.Railway applications – Fixed installations – DC switchgear – Part 2: DC circuit-breakers.
The rated characteristic values shall be specified by the purchaser. Nominal voltage values shall be selected from the values indicated in Table 1 of lC 61992-1; current values and track time constant (based on the track configuration which gives the largest track time constant) should have one of the preferred values listed in 5.1.2 of lEG 61 992-1.
These values should be confirmed by the supplier, who should indicate the rated values for the type of circuit-breaker proposed and supply any other relevant data.
All these values shall be stipulated in accordance with 5.3.2 to 5.3.4. Definitions are given in IEC 61992-1. Some data may be omitted by agreement.
5.3.2 Voltages
A circuit-breaker is identified by the following voltages:
— system voltages and limits (see 3.2.1 and 5.1.3 of lEG 61992-1);
— nominal voltage (Jo, (see lEG 60850):
— rated voltage UNe (see of IEC 61992-1);
— rated insulation voltage VNm (see of IEC 61992-1). It shall be equal to or higher than Umax;
— rated impulse withstand voltage UNi (see of IEC 61992-1);
— power-frequency voltage withstand level (dry) Ua (see and Table 1 of IEC 61992-1);
— maximum arc voltage (see of IEC 61992.1);
— rated auxiliary and control supply voltages (see of IEC 61992-1).
5.3.3 Currents
A circuit-breaker is defined by the following currents:
— conventional thermal current ‘th’‘the (see 3.2.3 and 3.2.4 of lEG 61992-1); rated service current ‘No (see 3.2.5 of IEC 61 992-1);
— rated short-circuit current ‘Nss (see 3.2.10 of lEG 61 992-1);
— rated short-time withstand current ‘Ncw (see 3.2.7 of IEC 61 992-1);
NOTE 1 Short-time ratings only apply to circuit-breakers not fitted with series trip devices, or in a unidirectional device where a series trip is inoperative. In practice, this would apply to a rectifier circuit breaker In the forward direction where a series trip only acts in the reverse direction.
NOTE 2 Rated short•time Currents do not need to have the same value as the rated short-circuit current 1Ng
— overload capability: the purchaser shall inform the supplier of the load cycle requirements (see 3.2.5, Note 2 of IEC 61992-1).
5.34 Short-circuit characteristics Rated short-circuit breaking and making capacities
These values are defined in 3.2.19 and 3.2.23 of IEC 61992-1 and are associated with the rated voltage UNe, the rated service current ‘No’ the rated short-circuit current ‘Nss’ the rated track time constant TNC and the class designation H-ec–, V-.o4-. S or C.
The rated short-circuit making capacity is the prospective peak value of the rated short-circuit current ‘Nss (see 3.2.10 of IEC 61992-1).
A rated short-circuit breaking capacity requires the circuit-breaker to be able to interrupt any short-circuit current of a value lower than or equal to this rated breaking capacity at the circuit time constant stipulated.
A H, V and S circuit-breakers having a breaking capacity at a rated track time constant TNC are capable of the same breaking capacity at all lower values of tack circuit time constant t. For Type C circuit breakers the initial rate of rise shall not exceed the limits given in Table 6.
The prospective maximum short-circuit current is the sum of the prospective short-circuit currents from all sources connected to the system. including rectifier converters and regenerative trains.IEC 61992-2 pdf download.

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