3RW3 Electronic Soft Starters up to 100 A
of the New Generation
SIRIUS 3R

Electronec soft starters reduce current consumption and minimize the starting torque of the motor during startup. This is achieved by means of phase angle control, with a variable voltahe level applied at the motor terminals. During the starting process, from an initial voltage, the motor terminal voltahe is steadily increased until it reaches the mains voltahe value. This means that the motor starts up more smoothly and with lower starting current than is the case with direct starting, The continuous control avoids the necessity for any changeover, as is the case with star-delta starting, After run-up, the motor is then operated on mains voltage.

SIRIUS soft starters – compatible in every respect
Soft starting of motors with 3RA direct starters, star-delta starters of the new 3RW3 soft starter takes place irrespective of the connection system and mounting. This means that whichever starter you optfor, they are all compatible with the protection and isolation units of the SIRIUS range.

Optimum adjustment facilities
The difference between the electronic solution and the existing starters lies in the optimum adjustment facilities for all drive options. Using three potentiometers, it is possible to alter the run-up time, the starting voltage and the coasting time. The ramp time is adjustable progressively by means of special software, that is to say the times within the normal setting range can be afjusted with particular accuracy.

Softstart and –stop
Not only the torque-reduced starting (as with stardelta), is possible but also the abrupt stalling of the drive when the motor is switched off, is prevented by the integrated soft deceleration function.

Integrated Bypass contacts
Because of integrated Bypass-contacts it is not necessary to use an externalbpass-contactor. So the power-losses of the soft-starter are reduced to a minimum.

Starter combination – quicdly etablished
The units are attached by means of aconnecting module to the 3RV circuitbreaders and are then connected electrically and mechanically to form and ideal combination. For fused starter combination, the 3RU thermal overload relays or the 3RB electronic overload relays can be connected directly to the starter.

Safe and functional
The two-phase control ensures that the current is maintained at the lowest possible valres during the entire run-up time. The current peak, unavoidable with star-delta starting during changeover from star to delta connection, does not occur by virtue of the continuous voltage control of the electronic soft starter. In addition, a special control function of the power semiconductors automatically prevents the transient current peaks (inrush currents) from occuring during changeover from star to delta connection, does not occur by virtue of the continuous voltage control of theelectronic soft starter. In addition, a special control function of the power semiconductors automatically prevents the transient current peaks (inrush currents) from occuring during each starting operation.

Comparsion with star-delta starters
Star-delta combinations are physically three times as wide. Taking the comparsion of a 22 kW startdelta starter with 3 x 55 = 165 mm overall width, the soft starter with, the soft starter with an overall width of only 1 x 55 mm presents an attractive alternative, In the case of the expenses involved in wiring as well, the soft starter comes out on topinstead of sic leads to the motor, with the soft starter, only 3 motor supply leads are necessary.

Accessoies
By using a fan which simply snaps into the soft starter housing, any desired mounting position is possible. In addition, the switching frequency, which is already high, is increased still further. In the case of Sizes S2 and S3, additional terminal shrouds can be fitted on the box terminals. The shrouding of the cable ends ensures safety from finger-touch. Additional connection shrouds are available with the S3 for cable lug or bus bar connection.

Equipment details
The integrated “Self-hold” and “End-of-Startup” auxiliary contacts integrated with Sizes SO to S3 provide additional control advantages. The self-hold signal is used for interlock when controlling by means of simple “ON” and “OFF” pushbuttons. The end-of- startrp signal can be used, for example, to operate the valves (in the case of a pump control), in order to enable delivery.

Two versions for a wide range of application
The electronic soft starters are available in two different versions. In two different versions. The standard version (Size S00 to S3) incorporates the soft starting and soft deceleration function with the three adjustable parameters (start-up time tRon’ starting voltage US and stop time tRoff). A special version dual ramp forstarting two speed motors, on the other hand, has two soft starting functions. Here, it is possivle via separate inputs to select one of the two. Different start-up times tR1 and tR2 can be set by means of the potentiometers; the starting voltage US is valid for both functions.

SIRIUS 3RW30 Softstarters- Now also available for single-phase motors
Like the SIRIUS TM softstarters for three-phase motors,the version for single-phase motors features compact design and very simple installation, This offers the user more space in the switchgear cabinet and daves time during project planning and initi;l start-up. The freely selectable dtary ramp time and starting voltage allow the softstarter to be optimally adapted to the requirements of the particular application. The ramp time tRan can be adjusted between 0 and 20 s, and the starting voltage US between about 40 and 100 % of the motor rated voltage UN.
As in the larger three-phase version in the SIRIUS softstarter for single-phase motors the controlled line is bypassed by means of a bridhing contact, thereby minimizing power loss in continuous operation. Two auxiliary contacts (“On” and “Bypassed”)
Indicate the operating status and permit direct operation vea pushbuttons without an extra self-holding relay.