Siemens 3RW4457-6BC44 880A Soft Starter SIRIUS

Siemens 3RW4457-6BC44 SIRIUS Soft Starter

Product Introduction

This section covers the Siemens 3RW4457-6BC44 in detail. This soft starter belongs to the reliable SIRIUS family. It provides a robust solution for motor control applications. The unit features a 880A operational current at 40°C. Users appreciate its integrated bypass contact system for energy efficiency. Moreover, this model supports both standard and inside-delta wiring configurations.

Key Technical Specifications

The 3RW4457-6BC44 delivers impressive performance for industrial motors. For a standard circuit at 400V, it offers 880A. This translates to 500kW of mechanical power. When you use the inside-delta circuit, the current rating increases to 1524A. Consequently, the power output reaches 900kW at 400V.

• Rated Operational Current (40°C): 880 A (Standard), 1524 A (Inside-Delta)

• Rated Power at 400V (40°C): 500 kW (Standard), 900 kW (Inside-Delta)

• Operating Voltage: 200 to 460 V AC

• Control Supply Voltage: 230 V AC (50/60 Hz)

• Integrated Bypass: Yes

• Motor Overload Protection: Yes

• Adjustable Current Limitation: Yes

Additionally, the device operates efficiently across different temperatures. At 50°C, the operational current is 780A. At 60°C, it is 693A. For inside-delta connections at 50°C, the rating is 1351A. At 60°C, it remains high at 1200A.

Mechanical and Environmental Data

This soft starter has a durable design for harsh conditions. Its dimensions are 510mm width, 640mm height, and 290mm depth. The mounting method uses screw fixing. You can rotate the unit +/-90° on a vertical surface. Furthermore, you can tilt it +/-22.5° to the front or back.

• Degree of pollution: 3 (according to IEC 60947-4-2)

• Insulation voltage rated value: 690 V

• Ambient temperature during operation: Up to 60 °C

• Installation altitude: Up to 5000 m above sea level

• Protection class (front): IP00

The device requires specific spacing for proper cooling. Keep at least 100mm space upwards. Allow 5mm on the sides. The downwards spacing must be 75mm.

Installation and Connection Guide

Proper wiring ensures the Siemens 3RW4457-6BC44 performs reliably. The main current circuit uses busbar connections. For auxiliary and control circuits, use screw-type terminals.

Main circuit connections:

• Finely stranded cable: 50 to 240 mm²

• Stranded cable: 70 to 240 mm²

• AWG cables: 2/0 to 500 kcmil

Auxiliary contacts configuration:

• Number of NO contacts: 3

• Number of CO contacts: 1

• Number of NC contacts: 0

For auxiliary contacts, you can use solid wires of 2x (0.5 to 2.5 mm²). For finely stranded wires with core end processing, use 2x (0.5 to 1.5 mm²). The maximum wire length is 500 meters.

First, mount the unit on a vertical surface using screw fixing. Next, connect the main power cables to the busbar terminals. Then, wire the control supply voltage (230V AC) to the appropriate terminals. Finally, connect the motor leads according to either standard or inside-delta configuration.

Important note: This is a phased-out product. Siemens recommends the successor type 3RW5556-6HA14 for new projects. However, the 3RW4457-6BC44 remains a reliable choice for existing installations requiring a replacement unit.

Power Loss and Efficiency

During typical operation at 40°C, the power loss is 250W. The continuous operating current can reach 115% of Ie at 40°C. This margin allows for temporary overload conditions without tripping.

Display and Control Features

The unit includes a display for fault signals. It also offers several protective functions. For instance, it evaluates thermistor motor protection. The device provides intrinsic device protection. You can use an external reset function. Additionally, it has a motor brake output component.

Frequently Asked Questions (FAQ)

1. Is the Siemens 3RW4457-6BC44 still in production?
No, this is a phased-out product. Siemens has discontinued the 3RW4457-6BC44. The official successor is the SIRIUS 3RW5 series, specifically the preferred type 3RW5556-6HA14.

2. Can I use this soft starter for inside-delta wiring?
Yes, absolutely. The 3RW4457-6BC44 supports both standard and inside-delta circuits. For inside-delta at 400V and 40°C, the rated current is 1524A and the power is 900kW.

3. What control supply voltage does this device require?
It requires a 230V AC control supply. This works for both 50Hz and 60Hz systems. The tolerance range is -15% to +10%.

4. How much space do I need around this soft starter for cooling?
You must maintain specific clearances. Leave 100mm above the unit. Keep 5mm on both sides. Allow 75mm below the unit. This spacing ensures proper airflow and cooling.

5. Does this unit have an integrated bypass contact system?
Yes, it does. The integrated bypass reduces power loss and heat generation. After the motor starts, the bypass contacts close. This allows the main current to bypass the thyristors, improving overall efficiency.