Description

1. Product Overview

Siemens 6RA7095-4KV62-0-Z is a four-quadrant fully digital DC drive unit under the SIMOREG DC Master 6RA70 series, designed for high-precision speed control of high-power DC motors. With a rated three-phase AC input of 460V and a rated DC armature current of 2000A, it is compatible with 1450kW DC motors. It enables stable four-quadrant operation including forward/reverse motoring and regenerative braking, with energy fed back to the power grid. It is widely adopted in heavy-duty industrial applications requiring wide speed regulation, fast dynamic response and frequent forward/reverse rotation, such as steel rolling, mine hoists, papermaking, metallurgical traction and large extrusion equipment.

Equipped with a microprocessor-based fully digital control architecture and a standard CUD1 main control board, the unit supports multiple setpoint modes including analog, digital and fieldbus. It integrates sophisticated dual closed-loop regulation algorithms for armature and excitation circuits, featuring speed-current double closed-loop speed regulation, field weakening speed-up, automatic fault diagnosis and parameter retention upon power failure. Parameter upload/download, waveform recording and fault traceability analysis can be realized via the DriveMonitor commissioning software. Optional communication boards such as Profibus-DP and SIMOLINK allow connection to PLC and DCS automation systems. It is applicable to new heavy-duty drive projects as well as spare part replacement and upgrade for legacy DC drive systems of the same specification.

2. Hardware Structure and Composition

2.1 High-power Thyristor Rectifier Power Unit

It adopts a three-phase fully-controlled bridge B6(A)C four-quadrant rectifier topology with disc-type high-power thyristor modules. The armature circuit features a rated DC voltage of 725V and a rated DC current of 2000A, with a short-term overload capacity of 180% rated current. An independent forced air cooling system is configured, with multiple built-in temperature sensors monitoring the temperature of thyristors and heat sinks in real time. The unit automatically derates or triggers over-temperature protection shutdown upon overheating. The excitation circuit adopts single-phase controlled rectification with a maximum DC excitation voltage of 375V and a rated excitation current of 40A, supporting constant excitation and field weakening speed regulation for motors. Fast semiconductor fuses are integrated in the power circuit to rapidly cut off the main loop under short-circuit faults and protect power devices from breakdown damage.

2.2 CUD1 Main Control & Signal Acquisition Unit

The core adopts the CUD1 basic control board. All digital input and output channels are designed with 2500V optoelectronic isolation to effectively resist electromagnetic interference from on-site frequency converters and high-voltage equipment. It accepts ±10V and 0~20mA analog speed setpoints, and supports multi-channel analog and digital status feedback to upload real-time signals including armature current, excitation current, rotating speed and unit operating faults. A high-precision speed feedback interface is embedded, supporting both pulse encoder and analog tachogenerator speed acquisition modes, achieving a steady-state speed control accuracy of 0.006% to guarantee speed stability without drift under low-speed and heavy-load conditions.

2.3 Operation Panel & Parameter Storage Unit

A detachable basic operation panel is provided as standard for local real-time display of operating speed, armature current, excitation current, DC voltage, fault codes and unit status, as well as local parameter modification and fault history query. The main control board is equipped with non-volatile memory to permanently store all control parameters, fault records and operating event logs after power failure. Combined with the DriveMonitor upper computer commissioning software, users can back up parameters in batches, record dynamic operating waveforms, facilitate equipment commissioning and troubleshooting, and copy parameters in batches for units of the same model.

2.4 Communication Expansion & Peripheral Interface Unit

Expansion slots are reserved on the main control board for optional high-speed synchronous communication cards including Profibus-DP, CANopen and SIMOLINK, realizing master-slave synchronous control of multiple drives and plant-wide networked centralized monitoring. Terminals for external emergency stop, main contactor interlock and braking logic control are reserved for connection to safety protection loops to implement emergency trip and fault-safe shutdown. The unit adopts a vertical metal cabinet structure with an IP20 protection rating, built-in shielding and noise reduction structure with a fan noise level of 87dBA, suitable for centralized installation in indoor high-voltage control cabinets.

2.5 Cabinet Heat Dissipation & Mechanical Installation Unit

Designed as a standard vertical cabinet with independent upper and lower air inlet and outlet ducts for heat dissipation. The cooling fan is equipped with fault detection to trigger system early warnings upon fan stall or aging. Physical zoning wiring is adopted for strong and weak current circuits with separate layout of power and control terminals to reduce crosstalk from high-voltage circuits to low-voltage control signals. Standard mounting cutout dimensions enable direct replacement of legacy high-power DC drives of the same series without modifying cabinet installation structures and main circuit wiring layouts.

3. Technical Specifications

3.1 Electrical Specifications

Input: 3-phase 460VAC (+15%/-20%), rated frequency 45~65Hz, rated main circuit input current 1660A; single-phase 460VAC supply for excitation circuit
Armature Output: rated DC voltage 725V, rated DC current 2000A, compatible with 1450kW DC motor; short-term overload capacity up to 180% rated current
Excitation Output: maximum DC voltage 375V, rated excitation current 40A
Control Accuracy: steady-state speed accuracy ±0.006% (encoder feedback mode); ±0.1% (analog tachometer mode)
Terminals: multiple opto-isolated digital I/O channels, 2 analog setpoint inputs, multiple analog status feedback outputs
Communication: local panel commissioning as standard; optional Profibus-DP, SIMOLINK, CANopen fieldbus
Control Mode: four-quadrant reversible operation, speed + current double closed-loop control; supports field weakening speed regulation and master-slave synchronous control

3.2 Environmental Specifications

Operating Temperature: 0℃~+40℃ (rated load operation); derating required for altitudes above 1000m; storage & transport temperature: -25℃~+70℃
Relative Humidity: 5%~95% RH, non-condensing, free of corrosive gas and conductive dust; environmental class 3K3
EMC: compliant with IEC 61000 Industrial Class A anti-interference standard, resisting burst, ESD and surge interference
Protection Class: IP20, for installation only in indoor ventilated high-voltage control cabinets

3.3 Mechanical Specifications

Mounting: floor-standing vertical cabinet installation
Overall Dimensions: 880mm (H) × 450mm (W) × 500mm (D)
Net Weight: approx. 145kg
Cooling: forced air cooling with fan fault detection and early warning
Optional Accessories: operation panel, various fieldbus communication boards, speed encoders, DriveMonitor commissioning software, line reactors, EMC filters

4. Product Functions and Features

Four-quadrant Regenerative Operation Saves Energy for Frequent Forward/Reverse Heavy-duty Applications

It realizes four-quadrant reversible speed regulation. During motor braking, mechanical energy is converted into AC power and fed back to the grid, eliminating the need for external high-power braking resistors and greatly reducing energy consumption and cabinet heat dissipation load. It is perfectly suited for frequently started, stopped and reversed heavy-duty equipment such as rolling mills, hoists and cranes, and avoids fire hazards caused by overheated braking resistors.

High-precision Double Closed-loop Speed Regulation plus Field Weakening Control for Stable Wide-range Speed Adjustment

Adopting PID double closed-loop regulation for speed and current, it ensures no speed drop or jitter under low-speed heavy-load conditions. Field weakening speed-up enables stable operation above the motor base speed, delivering a wide speed range and fast dynamic response to meet stringent tension and speed synchronization requirements in steel rolling and papermaking processes.

Comprehensive Hardware and Software Multi-level Protection Ensures Continuous Operation of High-power Equipment

It integrates more than 20 protection functions including overcurrent, overvoltage, undervoltage, thyristor over-temperature, motor earth fault, armature short circuit, field loss, encoder fault and phase loss. Upon fault occurrence, pulse signals are immediately blocked and the main contactor is tripped, while fault codes and real-time operating parameters at the fault moment are latched for rapid root cause identification and prevention of catastrophic damage to high-power drive equipment.

Rich Expandable Communication and Multi-drive Synchronous Control for Centralized Automated Management

Supporting mainstream industrial fieldbus protocols, it can be connected to DCS and PLC systems for remote start/stop, speed setpoint and remote fault uploading. When paired with the SIMOLINK optical fiber bus, high-precision master-slave synchronization of multiple drives can be achieved to satisfy tension synchronous linkage control for multi-stand rolling mills and multiple production lines.

Complete Commissioning and Maintenance Functions Reduce On-site Debugging and Servicing Workload

The upper computer software supports batch parameter backup, waveform recording and fault event traceability; one-click parameter copying enables rapid commissioning for identical units. Hierarchical parameter access lock prevents unauthorized on-site modification of critical process parameters. It also supports automatic fault reset and retry to resume operation after nuisance trips caused by transient grid disturbances.

Industrial-grade High-power Reinforced Cabinet Design Adapts to Harsh Industrial Sites

Optoelectronic isolation between strong and weak current circuits and insulation protection for power loops, together with full cabinet dustproof and noise reduction technology, enable long-term stable continuous operation in metallurgical, mining, papermaking and other plants with heavy dust, vibration and electromagnetic interference. Built-in temperature and fan status monitoring supports predictive maintenance and early fault warning.

5. Applicable Working Conditions and Application Scenarios

Four-quadrant speed regulation and tension control systems for high-power DC motors of main rolling mills, uncoilers and recoilers in metallurgical hot and cold rolling production lines.
Reversible drive and regenerative safety speed control projects for heavy-duty mine and port hoists, winders and lifting equipment.
Multi-drive synchronous closed-loop tension control for rewinding, traction and coating units in large-scale papermaking and film production lines.
High-precision wide-range DC motor speed control process systems for rubber extrusion, plastic calendering and large cable manufacturing equipment.
Spare part replacement for faulty legacy high-power 6RA70 series DC drives and automation & networking upgrade projects for drive systems.

SIEMENS 6RA7095-4KV62-0-Z Digital DC Speed Control Unit