Siemens 3RW4444-6BC44 Soft Starter 250A

Siemens 3RW4444-6BC44 SIRIUS Soft Starter for High Feature Applications

Product Introduction

The 3RW4444-6BC44 belongs to Siemens’ SIRIUS series of soft starters. This model handles very demanding motor control applications. You can use it for standard switching or inside-delta circuits. In standard mode at 40°C, it provides 250A. When you wire it for inside-delta, it delivers 433A at the same temperature. Such high current capacity makes it ideal for large industrial pumps, compressors, heavy fans, and conveyors.

Key Technical Specifications

The 3RW4444-6BC44 offers a rated operating current of 250A at 40°C for standard circuits. For inside-delta circuits, the current reaches 433A at 40°C. It delivers 132kW at 400V in standard mode. In inside-delta mode, it provides 250kW at 400V. The operating voltage range is 200 to 460V AC. Its control supply voltage is 230V AC at 50 or 60 Hz. You can adjust the motor current from 50A up to 250A. The minimum load is 8% of I_M. Furthermore, the continuous operating current reaches 115% of I_e at 40°C. Typical active power loss during operation is only 110W.

This soft starter includes an integrated bridging contact system and thyristors. It also features motor overload protection and an external reset option. Additionally, the adjustable current limitation gives you precise control. The device is ready for inside-delta circuits. One standout feature is the motor brake output. Another key advantage is its ability to evaluate thermal resistor motor protection. This significantly improves motor safety and longevity.

Temperature Derating Data

At 50°C, the standard current for the 3RW4444-6BC44 drops to 215A. At 60°C, it becomes 185A. For inside-delta at 50°C, the current is 372A. At 60°C, it is 320A. Therefore, you must consider ambient temperature when you plan the installation. Proper ventilation around the unit helps maintain full performance.

Control and Display Features

The control electronics use an AC supply at 230V. Frequency tolerance is ±10%. A built-in display shows fault signals clearly. This helps you identify issues quickly. Moreover, the device supports an external reset. This feature reduces downtime during fault conditions. The control supply voltage tolerances are -15% and +10% at both 50 Hz and 60 Hz.

Mechanical and Environmental Data

The 3RW4444-6BC44 has a width of 210 mm, a height of 230 mm, and a depth of 298 mm. Mounting is done with screw fixing. You can rotate it ±90° on a vertical plane. You can also tilt it ±22.5° forward and backward. Maintain clearance distances of 100 mm upward, 5 mm sideways, and 75 mm downward. The installation altitude can reach up to 5000 meters above sea level. Maximum cable length is 500 meters. Protection class is IP00. Ambient operating temperature goes up to 60°C. Storage temperature ranges from -25°C to +80°C.

Electrical Connections

For the main current circuit, the 3RW4444-6BC44 uses busbar connections. For auxiliary and control circuits, it uses screw-type terminals. It provides three NO contacts and one changeover contact for auxiliary contacts. There are no NC contacts. Conductor cross-sections for main contacts range from 70 to 240 mm² for finely stranded wires. For stranded wires, you can use 95 to 300 mm². For AWG conductors, the range is 3/0 to 600 kcmil at the front clamping point. You can also use DIN cable lugs from 50 to 240 mm². For auxiliary contacts, solid wires from 0.5 to 2.5 mm² are acceptable.

Frequently Asked Questions (FAQ)

1. Can the 3RW4444-6BC44 be used for both standard and inside-delta wiring?
Yes. The 3RW4444-6BC44 supports both standard circuits and inside-delta circuits. In inside-delta mode, it delivers a much higher current of 433A at 40°C.

2. What is the maximum motor power this soft starter can handle?
For a standard circuit at 400V and 40°C, it handles 132kW. For an inside-delta circuit at the same voltage and temperature, it handles 250kW.

3. Does this device include a motor brake output?
Yes. The 3RW4444-6BC44 comes with a motor brake output as a standard product component. This feature simplifies system wiring for quick stopping applications.

4. What clearance spaces are required around the unit?
You must leave 100 mm above, 5 mm on the sides, and 75 mm below the 3RW4444-6BC44. These spaces ensure proper cooling and safe operation.

5. Which shipping carriers do you use for this product?
We ship the 3RW4444-6BC44 via FedEx, UPS, or DHL. The actual carrier depends on your destination and order weight.