Product Overview

The 3RW4425-1BC44 belongs to the SIRIUS Series. Its product type is a Soft Starter. The product classification is Drives & Motion Control. The current price for this item is ¥5,280 RMB, and the product gross weight is 3.80 kg.

Siemens designed this soft starter for high-feature motor control applications. The product includes an integrated bridging contact system (bypass) and thyristors for smooth motor starting. This unit operates with a supply voltage of 200-460 V AC and a control supply voltage of 230 V AC. Furthermore, the 3RW4425-1BC44 supports both standard and inside-delta circuit configurations. Consequently, this soft starter provides flexible motor protection and starting solutions for various industrial applications.

Technical Specifications

Current and Power Ratings (Standard Circuit)

At 40°C with standard switching, the rated operating current reaches 57A . Meanwhile, the emitted mechanical power at 400V reaches 30kW . When the ambient temperature rises to 50°C , the current rating is 51A , and at 60°C , it drops to 45A . For 230V operation at 40°C, the power rating is 15kW . Therefore, users can select the appropriate configuration based on their ambient temperature and voltage requirements.

Current and Power Ratings (Inside-Delta Circuit)

When using inside-delta circuit at 40°C , the rated operating current reaches 99A . Additionally, the emitted mechanical power at 400V reaches 55kW . At 230V , the power rating reaches 30kW . At 50°C , the inside-delta current rating is 88A , while at 60°C , it is 78A . The inside-delta configuration allows the soft starter to handle higher currents, making it suitable for more demanding motor applications.

Voltage and Frequency Specifications

The operating voltage range for standard circuit spans 200 to 460 V AC . Similarly, for inside-delta circuit, the voltage range remains 200 to 460 V AC . The relative negative tolerance for both configurations is -15% , while the positive tolerance is +10% . The operating frequency is 50 to 60 Hz with a tolerance range of -10% to +10% . Thus, the 3RW4425-1BC44 accommodates common global power systems.

Control Supply

The control supply voltage is 230 V AC at both 50 Hz and 60 Hz . The relative negative tolerance for the control supply voltage is -15% , whereas the positive tolerance is +10% . This wide tolerance range ensures reliable operation even with fluctuating control power sources.

Motor Protection Features

The soft starter includes comprehensive motor protection functions. Intrinsic device protection and motor overload protection come standard. The device also supports evaluation of thermal resistor motor protection for accurate temperature monitoring. Users can perform an external reset after a fault condition. Moreover, the soft starter includes adjustable current limitation to prevent excessive starting currents.

Additional Functions

The product includes an outlet for engine brake , enabling rapid motor stopping when required. The minimum load is 8% of I_M , allowing the soft starter to work with lightly loaded motors. The adjustable rated current for motor overload protection has a minimum setting of 11A . The continuous operating current at 40°C reaches 115% of I_e , providing some overload margin.

Power Loss

The active power loss at operating current (40°C) during the operating phase is 36W typical . This low power loss reduces heat generation and improves overall system efficiency. Therefore, the 3RW4425-1BC44 maintains cool operation even under continuous running conditions.

Auxiliary Contacts

The soft starter includes 3 normally open (NO) contacts and 1 changeover contact for auxiliary circuits. It has 0 normally closed (NC) contacts . These contacts allow integration with external control systems and status indication devices. According to UL, the auxiliary contact rating is B300 / R300 .

Mechanical Dimensions

The width measures 170 mm , the height measures 192 mm , and the depth measures 270 mm . The device uses screw fixing for mounting. For proper heat dissipation, maintain a distance of 100 mm upward , 5 mm sideways , and 75 mm downward from other components. The mounting position allows rotation of ±90° on a vertical mounting plane. It also permits tilting of ±22.5° forward and backward.

Installation Altitude

The installation altitude reaches up to 5,000 meters above sea level. However, derating may become necessary above 1,000 meters. For altitudes between 1,000 and 5,000 meters, you should consult Siemens for specific derating guidelines.

Cable Length

The maximum cable length between the soft starter and the motor is 500 meters . This long distance provides flexibility for equipment layout in large facilities. For longer runs, additional filtering or output reactors may become necessary.

Electrical Connections (Main Circuit)

The main current circuit uses box terminals for electrical connections. Solid conductors require an acceptable cross-section ranging from 2.5 to 16 mm² . When dealing with finely stranded conductors that have end processing, the range expands to 2.5 to 35 mm² . For finely stranded conductors without end processing, you should use a cross-section between 4 to 50 mm² . Lastly, stranded conductors need a cross-section between 4 to 70 mm² . Additionally, the AWG range for main contacts spans from 10 to 2/0 .

Electrical Connections (Auxiliary Circuit)

The auxiliary and control current circuits use screw-type terminals . Solid conductors here require a cross-section of 2x (0.5 to 2.5 mm²) . Finely stranded conductors with end processing need 2x (0.5 to 1.5 mm²) . Meanwhile, the AWG range for auxiliary contacts is 2x (20 to 14) .

Ambient Conditions

The maximum operating temperature is 60°C , with derating starting at 40°C . The storage temperature ranges from -25°C to +80°C . The protection class is IP00 , meaning the device requires installation in an enclosure for protection against contact and dust.

UL/CSA Ratings

For standard circuit at 200/208V at 50°C, the HP rating is 15 hp . At 220/230V , the HP rating is also 15 hp . At 460/480V , the HP rating reaches 30 hp . For inside-delta circuit at 200/208V , the HP rating is 25 hp . At 220/230V , it reaches 30 hp . Finally, at 460/480V , the HP rating reaches 60 hp . These UL/CSA ratings ensure compliance for installations in North America.

Installation Guide

Follow these steps to install your 3RW4425-1BC44 correctly.

1. Select Mounting Location: Choose a vertical mounting surface. Ensure clearance of 100 mm above , 5 mm sideways , and 75 mm below the device.

2. Mount the Soft Starter: Secure the 3RW4425-1BC44 using screw fixing through the mounting holes. Tighten screws to the recommended torque.

3. Connect Main Power: Wire the three-phase supply to the input terminals. Use appropriate cable sizes based on your current rating (57A or 99A).

4. Connect Motor Leads: Wire the motor leads to the output terminals. For inside-delta circuit, follow the specific wiring diagram in the manual.

5. Connect Control Supply: Apply 230 V AC to the control supply terminals. This powers the internal control electronics.

6. Wire Auxiliary Contacts: Connect the 3 NO contacts and 1 changeover contact to your control system. Use these for status indication and interlocking.

7. Configure Parameters: Set the motor rated current, starting ramp time, and current limit using the integrated display and buttons.

8. Test Operation: Run a test start and verify smooth motor acceleration. Check that the bypass contactor engages after starting completes.

Package List

• 1 x 3RW4425-1BC44 SIRIUS Soft Starter

• 1 x Terminal label set

• 1 x Mounting instruction sheet

Frequently Asked Questions (FAQ)

1. What is the difference between standard circuit and inside-delta circuit?
Standard circuit connects the soft starter in series with the motor windings. In contrast, inside-delta circuit connects the soft starter inside the motor delta loop. Inside-delta allows the soft starter to handle 99A instead of 57A , giving 55kW instead of 30kW at 400V. Therefore, inside-delta provides higher power output from the same physical device.

2. Does the 3RW4425-1BC44 need external bypass contactors?
No, this soft starter includes integrated bridging contactors . After the motor reaches full speed, the internal bypass contacts close, taking the thyristors out of the circuit. Consequently, this design reduces power loss and heat generation during continuous running.

3. How do I reset the soft starter after a fault?
You can perform an external reset via a wired input signal. Alternatively, you can use the integrated display for manual reset. The product also supports automatic reset depending on your parameter settings.

4. What motor protection features does this soft starter provide?
The 3RW4425-1BC44 provides motor overload protection , intrinsic device protection , and thermal resistor motor protection evaluation . It also includes adjustable current limitation to prevent excessive starting currents.

5. Can I use this soft starter at high altitudes?
Yes, the installation altitude reaches 5,000 meters above sea level. However, derating becomes necessary above 1,000 meters due to reduced cooling efficiency. For altitudes between 1,000 and 5,000 meters, consult Siemens for specific current derating values.