Siemens 3RW4455-6BC44 Soft Starter 693A 400kW

Siemens 3RW4455-6BC44 SIRIUS Soft Starter for High Power Applications

Product Introduction

The 3RW4455-6BC44 belongs to the Siemens SIRIUS series. It handles large industrial motors with ease. This device limits inrush current effectively. It also reduces mechanical stress on driven equipment. Therefore, you get longer service life from pumps, fans, compressors, and conveyors. The built-in thyristors and bridging contactor save panel space. Consequently, this soft starter offers a compact and efficient starting solution for demanding environments.

Main Electrical Ratings

The 3RW4455-6BC44 operates at a rated voltage of 200–460V AC. The control supply voltage is 230V AC at 50 or 60 Hz.

For standard circuits at 40°C, the rated current is 693A. This supports a 400kW motor at 400V. At 50°C, the standard current is 615A. At 60°C, it becomes 551A.

For inside-delta circuits at 40°C, the rated current reaches 1200A. This allows a 710kW motor at 400V. At 50°C, the inside-delta current is 1065A. At 60°C, it is 954A.

Additionally, the adjustable current range starts from 138A. The unit allows 115% continuous overload at 40°C. Typical power loss is only 220W during operation. This high efficiency keeps your panel cool.

Protection and Control Features

This SIRIUS soft starter offers complete motor protection. It includes intrinsic device protection and motor overload protection. Furthermore, it supports thermal resistor 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 3RW4455-6BC44 has an outlet for an engine brake.

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 makes the 3RW4455-6BC44 suitable for many sites.

Electrical Connections

Main current circuit connections use busbars. The 3RW4455-6BC44 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.

Frequently Asked Questions (FAQ)

1. What is the power difference between standard and inside-delta for the 3RW4455-6BC44?
Standard connection delivers 400kW at 400V with 693A. Inside-delta connection delivers 710kW at 400V with 1200A. Therefore, inside-delta nearly doubles the power capacity.

2. Does the 3RW4455-6BC44 require an external bypass contactor?
No. This Siemens model includes an integrated bridging contactor. It automatically bypasses the thyristors after starting. As a result, heat loss stays low, and you save panel space.

3. What is the minimum motor current this soft starter can protect?
The adjustable motor overload protection starts at 138A. Below this value, the device may not detect overload conditions accurately. Consider a smaller soft starter for very low current motors.

4. Can I install the 3RW4455-6BC44 at high altitudes?
Yes. The unit works up to 5000 meters above sea level. However, above 1000 meters, you may need to derate the current. Consult the Siemens manual for exact derating factors.

5. Which shipping carriers do you use for this soft starter?
We use FedEx, UPS, and DHL for all shipments. Each order includes full tracking and insurance. Delivery typically takes 3 to 7 business days worldwide.