Siemens 3RW4456-6BC44 Soft Starter 780A 450kW

Siemens 3RW4456-6BC44 SIRIUS Soft Starter (Discontinued Model)

Important Product Status Notice

The 3RW4456-6BC44 is a phased-out product. Siemens no longer manufactures this unit. However, many existing installations still use it. Therefore, this page provides technical reference data for maintenance purposes. The preferred successor type is the 3RW5554-6HA14 from the SIRIUS 3RW5 series. For new projects, select the 3RW5 family instead.

Product Introduction

The 3RW4456-6BC44 belongs to the Siemens SIRIUS series. It controls large three-phase motors smoothly. This device limits inrush current effectively. It also reduces mechanical stress on pumps, fans, compressors, and conveyors. The built-in bypass contactor and thyristors save panel space. Consequently, this soft starter offers a compact solution for demanding applications.

Main Electrical Ratings

The 3RW4456-6BC44 operates at a rated voltage of 200–460V AC. The control supply voltage is 230V AC at 50 or 60 Hz. Insulation voltage is 690V.

For standard circuits at 40°C, the rated current is 780A. This supports a 450kW motor at 400V. At 50°C, the standard current is 693A. At 60°C, it becomes 615A.

For inside-delta circuits at 40°C, the rated current reaches 1351A. This allows an 800kW motor at 400V. At 50°C, the inside-delta current is 1200A. At 60°C, it is 1065A.

Additionally, the adjustable current range starts from 156A. The unit allows 115% continuous overload at 40°C. Typical power loss is only 214W during operation. Minimum load required is 8% of I_M.

Protection and Control Features

This SIRIUS soft starter offers complete motor protection. It includes intrinsic device protection and motor overload protection. Furthermore, it supports thermistor motor protection for accurate temperature monitoring.

You can reset the device externally after a fault. The current limitation is fully adjustable. The inside-delta circuit function comes standard. Moreover, the 3RW4456-6BC44 has a motor brake output.

For signaling, it provides three NO contacts and one changeover contact. A clear display shows fault signals instantly. Therefore, troubleshooting becomes quick and straightforward.

Mechanical Design and Mounting

The device measures 510 mm wide, 640 mm high, and 290 mm deep. It weighs 28.6 kg. The protection class is IP00, which suits enclosed control panels. Mounting uses screw fixing for secure installation.

You can rotate the unit ±90° on a vertical mounting plane. Additionally, you can tilt it ±22.5° forward or backward. Maintain these clearances for proper cooling: 100 mm upward, 5 mm sideways, and 75 mm downward.

The maximum cable length is 500 meters. Installation altitude can reach 5000 meters above sea level. This flexibility made the 3RW4456-6BC44 suitable for many sites during its production life.

Electrical Connections

Main current circuit connections use busbars. The 3RW4456-6BC44 accepts copper cables from 50 to 240 mm² for finely stranded wires. For stranded wires, the range is 70 to 240 mm². AWG cables from 2/0 to 500 kcmil are also compatible.

Auxiliary and control circuits use screw-type terminals. They accept solid wires of 2x (0.5 to 2.5 mm²). For finely stranded wires with end processing, the range is 2x (0.5 to 1.5 mm²). AWG sizes from 20 to 14 work well.

UL/CSA Ratings for Reference

For applications requiring UL/CSA compliance, here are the ratings. At 200/208V with inside-delta circuit at 50°C, the rated output is 450 hp. At 220/230V with standard circuit, it is 250 hp. With inside-delta at 220/230V, it reaches 500 hp.

At 460/480V with standard circuit at 50°C, the rated output is 600 hp. With inside-delta at 460/480V, it reaches 1050 hp. Auxiliary contact rating according to UL is B300/R300.

Ambient Conditions and Installation Guidelines

The operating temperature range goes up to 60°C. However, derating begins at 40°C. Storage temperature is from -25°C to +80°C. Meanwhile, the operating frequency range is 50 to 60 Hz, with ±10% tolerance.

For installation, ensure proper ventilation around the unit. Do not block the cooling paths. Use appropriate cable lugs for main terminals. Tighten all screws to the torque specified in the manual.

Frequently Asked Questions (FAQ)

1. Is the 3RW4456-6BC44 still available for purchase?
No. This model is phased out. Siemens has discontinued production. However, we may have limited remaining stock. Contact us for availability. Otherwise, please order the successor 3RW5554-6HA14.

2. What is the direct replacement for the 3RW4456-6BC44?
The preferred successor type is the 3RW5554-6HA14 from the SIRIUS 3RW5 series. It offers similar or better performance with modern features.

3. Can I mix a 3RW4456-6BC44 with a 3RW5 unit in the same system?
Yes, but careful configuration is required. The control logic and communication protocols differ. Therefore, using the same series for all units is strongly recommended.

4. What is the power difference between standard and inside-delta for this model?
Standard connection delivers 450kW at 400V with 780A. Inside-delta connection delivers 800kW at 400V with 1351A. Therefore, inside-delta gives nearly 78% more power.

5. Does the 3RW4456-6BC44 work with 480V systems?
Yes. For 460/480V at 50°C with inside-delta, it delivers 1050 hp. Always check the UL ratings table for exact values at different voltages.