Siemens 3RW4453-6BC44 Soft Starter 954A 560kW

3RW4453-6BC44 SIRIUS Soft Starter for High-Power Industrial Motors

The 3RW4453-6BC44 belongs to Siemens’ high-feature SIRIUS soft starter family. You can use this device for demanding motor starting applications up to 560kW. It significantly reduces mechanical stress and inrush current during startup. Moreover, this model provides complete motor protection and thermal monitoring for critical industrial processes.

Key Electrical Specifications of the 3RW4453-6BC44

This soft starter operates at a rated voltage of 200–460V AC. For standard three-phase circuits, the operating current reaches 551A at 40°C. When you use the inside-delta configuration, it delivers an impressive 954A at the same temperature.

The mechanical power output scales accordingly. At 400V with standard switching, you get 315kW. In inside-delta circuit, power output jumps to 560kW at 400V. Additionally, at 230V, standard switching provides 160kW while inside-delta gives 315kW.

Frequency support covers 50–60 Hz with ±10% tolerance. The adjustable motor current ranges from 110A up to the full rated value. Continuous operating current reaches 115% of Ie at 40°C without any performance degradation.

Control Supply and Integrated Protection Features

The 3RW4453-6BC44 requires a 230V AC control supply at either 50 Hz or 60 Hz. Voltage tolerance sits at -15% to +10%, making it suitable for regions with unstable grid conditions.

Built-in protection features are extensive. The unit includes intrinsic device protection and motor overload protection. It also evaluates thermistor inputs for precise motor temperature monitoring. Furthermore, you get an external reset function, adjustable current limitation, and full inside-delta circuit support.

A motor brake output comes standard with this model. The unit also includes an integrated bridging contact system and thyristors for reliable switching operations.

Mechanical Dimensions and Mounting Requirements

The 3RW4453-6BC44 measures 510 mm wide, 640 mm high, and 290 mm deep. At 67 kg, this is a substantial device designed for floor-standing cabinets or heavy-duty wall mounting.

Protection class is IP00 on the front. Mounting uses screw fixing with flexible positioning options. You can rotate the unit ±90° on a vertical surface. Tilting ±22.5° forward or backward is also acceptable for challenging installation spaces.

Required spacing includes 100 mm upward, only 5 mm sideways, and 75 mm downward. Maximum cable length reaches 500 meters between the soft starter and the motor. Installation altitude goes up to 5,000 meters above sea level.

Temperature Ratings and Derating Guidelines

Operating temperature ranges from -25°C to 60°C. However, derating begins at 40°C. Therefore, at 50°C the standard current drops to 494A. At 60°C it reduces further to 438A.

For inside-delta operation at 50°C, current becomes 856A. At 60°C, it decreases to 759A. Storage temperature spans -25°C to +80°C, giving you good flexibility for warehouse storage and logistics planning.

Terminal Connections and Conductor Sizes

Main current circuit connections use busbar terminals. For DIN cable lugs, finely stranded wires require 50–240 mm². Stranded wires accept 70–240 mm².

AWG conductors for main contacts range from 2/0 to 500 kcmil. This wide range accommodates various international wiring standards.

Auxiliary contacts accept solid wires of 2x (0.5–2.5 mm²). Finely stranded wires with end processing take 2x (0.5–1.5 mm²). For AWG conductors, auxiliary contacts accept 2x (20–14). Finely stranded AWG wires without end processing take 2x (20–16).

This model provides three normally open auxiliary contacts and one changeover contact. It includes no normally closed contacts, so plan your control circuit accordingly.

Frequently Asked Questions (FAQ)

1. What is the maximum motor power for the 3RW4453-6BC44?
In standard circuit at 400V, it handles 315kW. In inside-delta circuit at 400V, it handles 560kW. For 230V applications, inside-delta reaches 315kW.

2. Why is the inside-delta current (954A) much higher than standard current (551A)?
Inside-delta connection places the soft starter inside the motor's delta loop. This reduces the current through each thyristor by 1/√3, allowing the 3RW4453-6BC44 to control a higher power motor without increasing its component ratings.

3. Can I use this soft starter at 60°C ambient temperature?
Yes, but derating applies. Standard current drops to 438A at 60°C. Inside-delta current drops to 759A. Always plan your thermal budget accordingly for high-temperature environments.

4. What type of motor protection does the 3RW4453-6BC44 include?
The unit provides motor overload protection, thermistor (PTC) evaluation, adjustable current limitation, intrinsic device protection, and external reset capability.

5. What clearance space do I need around this 67 kg device?
You need 100 mm above, 75 mm below, and only 5 mm on each side. Despite its large size, the 3RW4453-6BC44 maintains the same compact spacing requirements as smaller SIRIUS soft starters.