Product Overview

The 3RW4427-1BC44 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 ¥6,850 RMB, and the product gross weight is 3.90 kg.

Siemens designed this soft starter for demanding motor control applications requiring higher power output. The product includes an integrated bypass contact system 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 3RW4427-1BC44 supports both standard and inside-delta circuit configurations. Consequently, this soft starter provides flexible motor protection and starting solutions for larger industrial applications up to 90kW.

Technical Specifications

Current and Power Ratings (Standard Circuit)

At 40°C with standard switching, the rated operating current reaches 93A . Meanwhile, the emitted mechanical power at 400V reaches 45kW . When the ambient temperature rises to 50°C , the current rating is 82A , and at 60°C , it drops to 72A . For 230V operation at 40°C, the power rating is 22kW . 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 161A . Additionally, the emitted mechanical power at 400V reaches 90kW . At 230V , the power rating reaches 45kW . At 50°C , the inside-delta current rating is 142A , while at 60°C , it is 125A . The inside-delta configuration allows this soft starter to handle substantially higher currents, making it suitable for very 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 3RW4427-1BC44 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 thermistor 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 a motor brake output for rapid motor stopping when required. The minimum load is 8% of rated current , allowing the soft starter to work with lightly loaded motors. The adjustable motor current for motor overload protection has a minimum setting of 18A . The continuous operating current at 40°C reaches 115% of Ie , providing some overload margin.

Power Loss

The active power loss at operating current (40°C) during the operating phase is 55W typical . This low power loss reduces heat generation and improves overall system efficiency. Therefore, the 3RW4427-1BC44 maintains cool operation even under continuous running conditions.

Auxiliary Contacts

The soft starter includes 3 normally open (NO) contacts and 1 changeover (CO) contact for auxiliary circuits. It has 0 normally closed (NC) contacts . These contacts allow integration with external control systems and status indication devices.

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 core end processing, the range expands to 2.5 to 35 mm² . For finely stranded conductors without core 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 core 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.

Environmental Categories (IEC 60721)

The 3RW4427-1BC44 complies with strict environmental standards according to IEC 60721. For transport conditions, the device meets 3K6 (no ice formation, no condensation), 3C3 (no salt mist), 3S2 (sand must not enter devices), and 3M6 requirements. When considering storage, the same categories apply: 3K6, 3C3, 3S2, and 3M6 . Under normal operation, the device also satisfies 3K6, 3C3, 3S2, and 3M6 standards. Consequently, this soft starter suits a wide range of demanding industrial environments.

UL/CSA Ratings (Standard Circuit)

At 200/208V with standard circuit at 50°C, the HP rating is 25 hp . This UL/CSA rating ensures compliance for North American installations requiring standard circuit configuration.

Installation Guide

Follow these steps to install your 3RW4427-1BC44 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 3RW4427-1BC44 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 (93A or 161A).

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 CO 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 3RW4427-1BC44 SIRIUS Soft Starter

• 1 x Terminal label set

• 1 x Mounting instruction sheet

Frequently Asked Questions (FAQ)

1. What is the power difference between standard and inside-delta circuits?
Standard circuit delivers 45kW at 400V with 93A . In contrast, inside-delta circuit delivers 90kW at 400V with 161A from the same physical device. Therefore, inside-delta provides double the power output.

2. Does the 3RW4427-1BC44 need external bypass contactors?
No, this soft starter includes integrated bypass 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. What is the minimum adjustable current setting for motor protection?
The adjustable motor current for motor overload protection has a minimum setting of 18A . This allows the soft starter to protect smaller motors connected to the same power range.

4. What environmental conditions can this soft starter withstand?
The 3RW4427-1BC44 meets IEC 60721 categories 3K6, 3C3, 3S2, and 3M6 for transport, storage, and operation. It tolerates no ice formation, no condensation, no salt mist, and limited sand ingress.

5. What is the typical power loss of this soft starter during operation?
The typical power loss is 55W at operating current and 40°C during the operating phase. This low loss ensures efficient operation and reduced cooling requirements.