Description

Siemens 6RA7095-4KV62

1. Basic Information

Model: 6RA7095-4KV62

Brand: Siemens (SIMOREG DC Master 6RA70 series high-power 4-quadrant DC converter speed control unit, a complete dedicated drive assembly for industrial high-power DC motors)

Product Positioning

The 6RA7095-4KV62 is a high-end high-power 4-quadrant fully digital DC speed control rectifier in the 6RA70 series, designed for high-precision speed regulation and torque closed-loop control of high-power separately excited DC motors. Adopting a 16-bit microprocessor full-digital computing architecture, it realizes independent dual closed-loop regulation of armature and field excitation, supports 4-quadrant regenerative energy feedback operation, and adapts to working conditions featuring heavy loads, shock loads and frequent forward/reverse rotation. With a rated power of 1450 kW and a rated DC output current of 2000 A, it serves as the core power control unit for high-power DC drive systems such as metallurgical rolling mills, heavy papermaking equipment, large hoists, mine traction devices and electrolysis power supplies.

Hardware Architecture

The unit adopts a 3-phase fully controlled bridge 4-quadrant rectifier topology. Its main power circuit is equipped with high-power thyristor modules, integrating independent armature rectifier bridges and field excitation rectifier loops to enable bidirectional energy flow under motoring and regenerative feedback operating modes. It is equipped with an industrial-grade 16-bit microprocessor as the main controller, embedded with a triple closed-loop algorithm library for current, speed and torque control. Onboard standardized terminal interfaces, operator panel interfaces, multi-channel programmable DI/DO and analog AI/AO channels are provided. A forced air cooling system comes as standard, consisting of high-power centrifugal fans and large-area heat dissipation fins, with built-in fan speed monitoring and over-temperature cut-off protection circuits.

Galvanic isolation between high and low voltage circuits is implemented throughout the unit. Varistors and RC absorption circuits are integrated to suppress grid surges and commutation overvoltages. Multi-level hardware protection logic covers overcurrent, overvoltage, undervoltage, field loss, earth faults and heat dissipation failures. Multi-protocol communication expansion is supported, including PROFIBUS-DP, SIMOLINK and CAN bus, allowing connection to PLCs and upper DCS systems for remote parameter tuning and monitoring.

Mounting Specifications

This is an integrated floor-standing high-power cabinet unit intended for fixed installation in standard industrial low-voltage power distribution rooms. Anchor bolt mounting holes are reserved at the bottom. Due to its heavy weight, the mounting base must provide sufficient load-bearing capacity and seismic resistance. An independent front and rear air duct ventilation layout is adopted, with a separated design of the front operator panel area and rear power wiring zone, and dedicated wiring troughs for separating strong and weak current circuits.

For the forced air cooling design, standardized ventilation clearance must be reserved on all sides (top, bottom, front and rear) of the unit; fully enclosed packaging or air duct shielding is prohibited. The unit has passed industrial seismic, vibration and shock resistance tests, capable of long-term operation under vibration caused by frequent start-stop cycles of heavy workshop equipment, complying with the industrial standard of 7×24-hour uninterrupted heavy-load continuous operation.

Compatible Systems

It is specially matched with high-power separately excited DC motors (725 VDC armature rating). Supporting accessories include Siemens 6RA70 series operator panels, communication expansion boards, field excitation auxiliary units and external braking/regenerative feedback assemblies. It seamlessly interfaces with S7-300/400/1500 series PLCs, DCS distributed control systems, upper HMI monitoring terminals and fault data recorders.

It adapts to complete drive control systems such as main rolling line drives, large winches, electrolysis rectifiers and heavy extruders, and supports master-slave synchronous linkage control of multiple units via SIMOLINK.

Product Features

4-quadrant reversible operation with full energy regeneration capability; braking energy can be fed back to the grid without an additional regeneration cabinet, delivering remarkable energy-saving effects.
Dual independent closed-loop control: armature current-speed closed-loop + field weakening speed regulation closed-loop, featuring a wide field weakening range and stable constant-power operation at high speeds.
Short-time overload capacity of 180% rated current, suited for shock loads of rolling mills and instantaneous high-torque conditions during hoist startup.
Fully digital parameterized commissioning, built-in standardized industry process macro programs, supporting one-click adaptive gain tuning for loads.
Multi-bus industrial communication expansion, supporting remote monitoring, fault uploading and remote parameter modification.
Comprehensive hardware fault diagnosis; fault codes accurately locate all types of abnormalities in circuits, power sections, heat dissipation systems and motor sides.
Independent forced air cooling with real-time fan status monitoring; dual over-temperature protection including staged power derating followed by full output cutoff.

2. Technical Specifications

2.1 Power & Electrical Parameters

3-phase AC armature input: 3AC 690 V (permissible fluctuation range: +10% / -20%), 45～65 Hz
Rated armature input current: 1658 A
Rated DC armature output voltage: 725 VDC
Rated DC armature output current: 2000 A
Short-time overload capacity: 180% In (cycle complies with the standard 6RA70 load cycle curve)
Rated unit power: 1450 kW
2-phase AC field excitation input: 2AC 460 V (permissible fluctuation range: +15% / -20%), 45～65 Hz
Cooling fan power supply: independent dedicated fan circuit; rated fan current 1.25 A, air volume 2400 m³/h, noise level 87 dBA
Operating mode: 4-quadrant (4Q) reversible motoring / regenerative feedback operation

2.2 Control & Interface Parameters

Control core: 16-bit microprocessor full-digital closed-loop calculation; current loop cycle 0.1 ms, adjustable speed loop
Control modes: three basic modes (torque closed-loop, speed closed-loop, current limiting), supporting field weakening speed boosting
Digital I/O: multi-channel programmable 24 V DI/DO, configurable for enable, fault feedback, limit switches, emergency stop and running status signals
Analog channels: ±10 V analog setpoint input, analog speed/torque feedback output for external instrument acquisition
Communication expansion: native PROFIBUS-DP support; optional expansion boards for SIMOLINK high-speed synchronous fiber bus, CAN and DeviceNet
Operator unit: matched with standard 6RA70 OP1S/OP2S operator panels for local parameter configuration, status display and fault code reading

2.3 Thermal & Environmental Parameters

Cooling method: high-power forced centrifugal air cooling; independent fan circuit with real-time rotation speed fault monitoring
Operating ambient temperature: 0℃～+45℃; automatic power derating above 45℃, maximum permissible short-term ambient temperature +50℃
Storage & transportation temperature: -40℃～+70℃
Operating humidity: 5%～95% RH, non-condensing; condensation inside the cabinet is forbidden
Protection class: IP20 cabinet; for indoor use only in clean and dry power distribution rooms; outdoor, humid or corrosive environments are prohibited
EMC class: complies with EMC standards for industrial high-power drives; built-in input EMC filter and commutation absorption circuits to suppress harmonics and electromagnetic interference

2.4 Structural & Physical Parameters

Unit form: integrated floor-standing high-power rectifier cabinet with a split front-rear compartment layout (operator compartment / main power circuit compartment)
Mounting method: floor-mounted and fixed with anchor bolts; load-bearing reinforcement of the base is required, with dedicated independent ventilation air ducts
Wiring zoning: strict separation of strong and weak current circuits; power cables, control cables and communication cables routed in separate troughs, with reserved shield grounding terminals

3. Key Features

3.1 High-Power 4-Quadrant Regenerative Drive for Heavy Shock Loads

It supports complete 4-quadrant operation: forward motoring, forward regeneration, reverse motoring and reverse regeneration. Braking energy is directly fed back to the grid, greatly reducing energy consumption and maintenance costs for braking resistors. With a short-time overload margin of 180% rated current, it perfectly adapts to frequent shock loads and high-torque startup conditions of hot rolling mills, heavy hoists and mine traction equipment, with no low-speed torque attenuation.

3.2 Dual Independent Armature & Field Closed Loops for Wide Field Weakening Speed Range

Dual control architecture combining outer speed-inner armature current closed-loop and independent field weakening control. Full torque output is stably maintained at low speeds, while constant-power speed boosting is realized via field weakening at high speeds, delivering a wide speed regulation range and minimal speed fluctuation to meet high-precision speed control requirements for precision rolling and high-speed traction. The full-digital algorithm automatically compensates for armature voltage drop and field excitation attenuation without repeated manual calibration.

3.3 Fully Digital Parameterized Commissioning with Built-In Process Macros

All control logic, limit values and protection thresholds are set via parameter codes. Standard industry macros for rolling mills, hoists, electrolysis and other applications are preinstalled, supporting automatic motor identification and adaptive gain tuning to drastically shorten on-site commissioning cycles. Dual operation channels are available via local operator panel and remote fieldbus; parameters can be uploaded for backup and downloaded in batches.

3.4 Multi-Industrial Bus Networking for Synchronous Linkage of Multiple Units

PROFIBUS-DP enables connection to plant-wide DCS/PLC systems, while the SIMOLINK high-speed fiber bus realizes master-slave synchronous drive control for multiple 6RA70 units. Precise synchronization of speed and torque across multiple motors adapts to complete production line control such as tandem rolling mills and multi-roller synchronous lines, featuring ultra-low data transmission delay and high synchronization accuracy.

3.5 Multi-Stage Hardware Protection for Safe and Controllable Unit Operation

Multi-layer protection functions are integrated, covering field loss, armature earth faults, thyristor short circuits, overcurrent, overvoltage, undervoltage, cooling fan faults and staged over-temperature protection (power derating followed by full shutdown). When a fault is triggered, trigger pulses are immediately blocked and power output cut off. Fault codes and operating waveforms captured before and after the fault are stored simultaneously for rapid root-cause troubleshooting, preventing major equipment failures such as burnout of DC motors and power devices.

3.6 Independent Forced Air Cooling System for Long-Term Stable Heavy-Load Operation

Continuous forced heat dissipation is provided by large-flow centrifugal fans with real-time fan rotation speed monitoring; faults are immediately reported upon fan stall or abnormal rotation speed. Multi-level temperature control logic first reduces output power under high ambient temperatures, and shuts down the unit only if the temperature continues to exceed limits, eliminating overheating damage to main circuit thyristor modules during prolonged high-power heavy-load operation.

4. Working Principle

The Siemens 6RA7095-4KV62 realizes speed regulation control of high-power DC motors based on core principles of 3-phase fully controlled 4-quadrant rectifier topology + microprocessor dual closed-loop digital calculation + bidirectional energy regeneration + multi-stage full-condition protection.

After power-on, the control circuit first performs self-inspection of the cooling fan, field excitation loop, power thyristors, digital I/O and communication links. System enable is permitted only if self-inspection passes. 3-phase 690 V AC power feeds the main power bridge, while an independent 2-phase 460 V power supply supplies the field excitation rectifier unit. Speed/torque setpoint signals from the upper controller are sent to the main control chip. Calculated via outer speed and inner current dual closed loops, six-channel phase-shift trigger pulses for thyristors are output to adjust the DC rectified output voltage, thereby controlling armature circuit current and motor output torque.

For braking or reverse rotation conditions, the unit automatically switches to the regenerative rectifier quadrant, inverting the motor’s inertial kinetic energy into AC power and feeding it back to the 3-phase grid to achieve energy-saving resistance-free braking. The field excitation loop is independently controllable: full excitation delivers high torque at low speeds, while automatic field weakening enables constant-power speed boosting at high speeds.

Throughout operation, the unit synchronously monitors armature current, DC bus voltage, field excitation current, cooling fan rotation speed, internal cabinet temperature and earth leakage signals. If any parameter exceeds the threshold, multi-stage protective actions are executed sequentially: power derating, trigger pulse blocking and full unit shutdown. Fault codes and operating data are stored and uploaded to the local panel or upper monitoring system for visual fault tracing.

5. Application Scenarios

Main drive for metallurgical hot/cold rolling mills: primary drive for sheet and section rolling lines, handling frequent shock loads with 4-quadrant regenerative braking and high-precision speed synchronization control.
Heavy lifting and mine hoist equipment: main drive for large mine winders and steel plant overhead cranes, supporting heavy-load startup and regenerative braking during upward/downward travel with stable torque and no load slipping.
Large papermaking and film stretching production lines: DC main drive for high-speed stretching rollers and rewinders, offering wide speed regulation and multi-roller synchronous linkage control.
High-power electrolysis rectifier power supplies: high-precision constant-current DC power sources for non-ferrous metal electrolysis and electroplating.
Main drive for heavy extrusion and forging equipment: high-power DC drive for hydraulic auxiliary extruders and forging main machines, delivering short-time ultra-high torque output.
Heavy traction locomotives for ports and mines: ground heavy-duty traction equipment with frequent start-stop and forward/reverse cycles, operating with energy-saving regenerative feedback.