Operation - Siemens 3VA1 100 A Manual

Description
2.3 Technical details
2.3.2

Operation

①
②
The main contacts of the molded case circuit breakers are opened and closed by means of a
handle mounted on the front of the unit. All contacts open and close simultaneously on all
3VA molded case circuit breakers in response to the following events:
● The handle is moved from OFF to ON.
● The handle is moved from ON to OFF.
● The tripping mechanism is activated by a trip unit.
● The tripping mechanism is activated by auxiliary releases (e.g. shunt trips, trip units).
Reclosing the circuit breaker contacts from the TRIP position
Follow the steps below to reclose the circuit breaker contacts from the TRIP position:
1. Move the handle to the OFF position.
2. Move the handle to the ON position.
→ The breaker contacts are now closed.
Free tripping
All 3VA molded case circuit breakers have a free tripping capability. This function ensures
that the breaker cannot be prevented from tripping even if the operator blocks or is held
manually in the ON position or if the breaker is about to close.
Follow the steps below to test the free tripping function in order to verify that the breaker's
mechanical release system is working correctly:
1. Move the handle to the ON position.
2. Hold the handle in the ON position and press the button marked <PUSH TO TRIP>.
→ The circuit breaker trips and opens the main contacts.
→ The handle moves quickly into the TRIP position as soon as you release it.
Failure of the molded case circuit breaker to trip indicates that it is defective and must be
replaced.
50
ON: Main contacts closed
TRIP: Switching position following a trip
③
OFF: Main contacts open
④
PUSH TO TRIP: Initiates a mechanical trip
Manual, 04/2015, A5E03603177010-02
3VA molded case circuit breakers