3RV Motor Starter Protectors/Circuit Breakers up to 100 A General data System protection The 3RV10 and 3RV11 motor starter protectors for motor protection are also suitable for plant protection. A fuse is connected in parallel with each conducting path of the motor starter protector. When a fuse blows, the current flows through the parallel conducting path and trips the motor starter protector. In order to prevent premature tripping due to phase failure sen- sitivity, the three conducting paths must always be uniformly loa- ded. The conducting paths must be connected in series in the case of single-phase loads.
The 3RV16 11-0BD10 motor starter protector for fuse monitoring must be equipped with a transverse or lateral auxiliary switch (see "Accessories") that signals a tripping operation of the motor starter protector and thus the tripping of the fuse, or switches off all poles of the disrupted electric circuit with the help of an ap- propriate switching device. The 3RV17 and 3RV18 circuit breakers are suitable for system protection and at the same time they are approved as circuit breakers according to UL 489 and CSA C22.2 No. 5-02 for 100 % rated current (100 % rated breaker).
Short-circuit protection for starter combinations The 3RV13 motor starter protectors for starter combinations in sizes S0, S2 and S3 provide short-circuit protection with the help of a contactor and overload relay combination. Like the motor starter protectors for motor protection, they are equipped with short-circuit releases which are permanently set to a value equivalent to 13 times the rated current of the motor starter protectors. They are not equipped with overload releases. On overload, the overload relay triggers the contactor, the motor starter protector remains closed. Only when a short-circuit occurs in the feeder does the motor starter protector trip as well.
Motor starter protector for fuse monitoring Notes on safety The motor starter protector for starter combinations must always be used in combination with an overload relay because the motor starter protector alone cannot protect the motor and itself against overload. When monitoring fuses with safety isolating functions, a warning sign must be affixed near the fuses indicating that voltage may still be present through the parallel circuit of the monitoring equipment assumed to be isolated after the fuse has been remo- ved and if the monitoring equipment is not switched off.
Transformer protection When control transformers are protected on the line side, the high inrush currents generated at the time the transformers are switched on often cause spurious tripping in the protection me- chanisms. We recommend the following text for this warning: Caution! For safety isolation, also switch off fuse monitoring equipment with the item code ...... 3RV14 motor starter protectors in sizes S0 and S2 and 3RV18 circuit breakers in size S0 for protecting transformers are there- fore fitted with electronic trip units which are permanently set in the factory to a value equivalent to 20 times the rated current.
For the 3RV17 circuit breakers in sizes S0 and S3 these electronic trip units are set in the factory to approximately 13 times the ra- ted current. The 3RV16 11-0BD10 motor starter protector for fuse monitoring is suitable for the following voltages: AC 50 Hz/60 Hz from 24 V to 690 V and up to 450 V DC. Fuse monitoring with 3RV16 11-0BD10 motor starter protector is not permissible in feeders with power controllers that can induce DC feedback of higher values when an error occurs. Motor starter protectors can thus be used to provide line-side protection for transformers, the inrush peak currents of which are up to 30 times the rated current.
With parallel cables and meshed systems, the motor starter protector will only trip, and a signal will be output to indicate this, if the voltage difference across the motor starter protector is at least 24 V. The 3RV17 and 3RV18 are approved as circuit breakers accor- ding to UL 489 and CSA 22.2 No. 5-02 for the protection of transformers, the 3RV18 circuit breakers size S0 are designed specially for the protection of transformers with high inrush cur- rent. Use of IT systems (IT networks) 3RV1 motor starter protectors are suitable for operation in IT systems according to IEC 60947-2. In the event of a three- pole short-circuit, their response in this system is the same as in others:
Therefore, the same short-circuit breaking capacity I cu and I cs applies, (see "Technical specifications") . This version of motor starter protector is not necessary in the case of control-power transformers with low inrush currents, such as control transformers from Siemens. 3RV1 motor starter protectors for motor protection can be used in this case. An initial fault (ground fault) does not necessarily force immedi- ate disconnection of the network when operating IT systems. If a second independent error occurs (ground fault), the switching capacity of the motor starter protector might be reduced.
Main and EMERGENCY-STOP switches The 3RV10, 3RV11, 3RV13, 3RV14 and 3RV16 motor starter protectors comply with the isolating function to IEC 60947-2, the- refore they can be used – taking IEC 60204-1 into account – as main and EMERGENCY-STOP switches. This is the case if both ground faults occur in different phases and if one of the ground faults occurs on the input side and the other on the outgoing terminal of the motor starter protector. 3RV19 .6-2. door-coupling rotary operating mechanisms for heavy duty also comply with the requirements for the isolating function.
In order to maintain the short-circuit function of the motor starter protector even with two independent ground faults (double ground faults), the reduced short-circuit breaking capacity with double ground faults must be taken into account in IT systems I cuIT (see "Technical specifications") . If a ground fault is instanta- neously recognized and remedied (ground-fault monitoring), the risk of double ground fault and thus reduced short-circuit brea- king capacity I cuIT can be minimized. Fuse monitoring The 3RV16 11-0BD10 motor starter protector size S00 is used for fuse monitoring. 11 Siemens · 2009