3RV Motor Starter Protectors/Circuit Breakers up to 100 A
General data
8Siemens · 2012
System protection
The 3RV10 and 3RV11 motor starter protectors for motor
protection are also suitable for plant protection.
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 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 si-
zes 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.
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.
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.
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.
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.
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.
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.
Main and EMERGENCY-STOP switches
The 3RV10, 3RV11, 3RV13, 3RV14 and 3RV16 motor starter
protectors comply with the isolating function to IEC 60947-2,
therefore they can be used – taking IEC 60204-1 into account –
as main and EMERGENCY-STOP switches.
3RV19 .6-2. door-coupling rotary operating mechanisms for
heavy duty also comply with the requirements for the isolating
function.
Fuse monitoring
The 3RV16 11-0BD10 motor starter protector size S00 is used for
fuse monitoring.
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.
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.
Motor starter protector for fuse monitoring
Notes on safety
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.
We recommend the following text for this warning:
Caution!
For safety isolation, also switch off fuse monitoring equipment
with the item code ......
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.
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.
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 Icu
and Ics applies, (see "Technical specifications").
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.
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.
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
IcuIT (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 IcuIT can be minimized.