Circuit Breakers

3RV1 circuit-breakers are compact, current limiting circuitbreakers which are optimized for load feeders. The circuitbreakers are used for switching and protecting three-phase induction motors of up to 45 kW at AC 400 V and for other loads with rated currents of up to 100 A.

Short-circuit protection

If a short-circuit occurs, the short-circuit releases of 3RV1 circuitbreakers isolate the faulty load feeder from the mains supply and thus prevent further damage.

Circuit-breakers with a short-circuit breaking capacity of 50 kA or 100 kA are virtually short-circuit proof at a voltage of AC 400 V, since higher short-circuit currents are not to be expected in practice. Motor protection The tripping characteristics of 3RV10/3RV11 circuit-breakers are designed mainly to protect three-phase induction motors.

The circuit-breakers are therefore also referred to as motor circuit-breakers. The rated current In of the motor to be protected is set on the setting scale. Factory setting of the short-circuit release is 13 times the rated current of the circuit-breaker. This permits trouble-free start-up and ensures that the motor is properly protected.

The phase failure sensitivity of the circuit-breaker ensures that it is tripped in time in the event of a phase failure and overcurrents that occur as a result in the other phases.
Circuit-breakers with thermal overload releases are normally designed in accordance with trip class 10 (CLASS 10). Circuitbreakers of sizes S2 and S3 are also available in class 20 (CLASS 20) and therefore allow motors to be started up under arduous conditions.

Motor protection with overload relay function (automatic reset)

Circuit-breakers for motor protection with overload relay function are designed for the protection of three-phase induction motors.

They are equipped with the same short-circuit release and overload release as circuit-breakers for motor protection without overload relay function. The circuit-breaker always remains closed in the event of an overload. The overload release activates only two auxiliary contacts (1 NO + 1 NC). The overload trip can be signaled to a higher-level control with the help of these auxiliary contacts.

Generally, it is also possible to open a downstream contactor directly.
The overload signal is reset automatically. The circuit-breaker itself only trips if a short-circuit occurs downstream.

Plant protection

The 3RV10/3RV11 circuit-breakers for motor protection are also suitable for plant protection.
In order to prevent premature tripping due to phase failure sensitivity, the three conducting paths must always be uniformly loaded. The conducting paths must be connected in series in the case of single-phase loads.

Downloads:

Sirius Circuit Breaker Technical catalogue. (PDF - 2.5MB)