Descriere

VA88 circuit breakers are intended for conducting current in normal mode and switching it off at short circuits, overload, inadmissible bucking as well as operational actuation and tripping of electric circuit parts. They are designed for use in electric units having the operative voltage limited to 400 V per rated current from 12,5 to 1600 A. Correspond to the requirements of EN 60947-1, EN 60947-2. VA88 circuit breakers with MR211 electronic trip unit ensure overload and short-current protection with the help of an electronic overcurrent release. This allows securing high reliability, actuation accuracy and independence from the ambient conditions. Electronic trip unit does not require a separate power source and guarantees correct protection operation at load currents not less than 15% from the rated value even if the voltage is present only in one phase. Protection block includes three current transformers, an electronic module and a trip electromagnet influencing directly on the breaker’s mechanism. Current transformers installed inside the trip unit casing ensure supplying power to the electronic circuit and working out signals necessary for performing protection functions. Protection characteristics (actuation settings) are chosen by the consumer directly on the front panel by adjusting DIP switches in accordance with the indicated mnemonic diagram. Owing to the wide range of settings adjustment, MR211 electronic trip unit can be used in any distribution networks requiring reliability and actuation accuracy.Easy independent installation of auxiliary devices:
– signal contact;
– auxiliary contact;
– undervoltage trip;
– shunt trip;
– rotary handle;
– motor control;
– plug-in panel;
– pull-out panel.
Standard set of each circuit breaker consists of connecting busbars or cable lugs (depending on the size), phase separators, a set of screws and nuts for its mounting onto an installation panel.Position of connection for main current circuit: EV000154
Setting range over-current release: (1,5÷12) In
Number of auxiliary contacts as normally closed contact: 0
Number of auxiliary contacts as normally open contact: 0
Number of auxiliary contacts as change-over contact: 0
Number of poles: 3
Device construction: EV009212
Rated surge voltage invariability: 8
Rated voltage: 400
Rated short-circuit breaking capacity lcu at 400 V, 50 Hz: 35
Rated permanent current Iu: 250
Nominal operating max breaking capacity: 25
Nominal rated voltage: 400
Nominal rated current: 250
Degree of protection (IP): EV006405
Connection type main current circuit: EV000415
Type of control element: EV000421
Mains frequency: 50