SINAMICS S120 Cabinet Drive System Selection Guide
The SINAMICS S120 drive system is a modular, high-performance solution for demanding industrial applications. Available in cabinet-based configurations, it offers flexibility, scalability, and a wide range of components to build tailored drive systems. This guide walks through the key cabinet units, system components, and selection considerations to help engineers and system integrators design efficient and reliable drive solutions.
Cabinet-Based Drive Units Overview
SINAMICS S120 cabinet units come in two main cooling variants: air-cooled and liquid-cooled. Each type includes several functional units that can be combined to form a complete drive system. The air-cooled range is suitable for standard environments, while liquid-cooled units are ideal for high-power applications or where ambient conditions are challenging.
| Unit Type | Cooling Method | Typical Power Range | Key Features |
|---|---|---|---|
| Basic Line Module | Air / Liquid | Up to several MW | Uncontrolled rectifier, robust, cost-effective |
| Active Line Module | Air / Liquid | Up to several MW | Regenerative, low harmonics, controlled DC link |
| Motor Module (Inverter) | Air / Liquid | 0.55 kW – 1200 kW+ | Vector/servo control, scalable, booksize/chassis |
| Active Filter Cabinet | Air / Liquid | Compensates up to 100% harmonics | Improves power quality, reduces THDi |
Air-Cooled Cabinet Units
Air-cooled SINAMICS S120 cabinets are designed for indoor installation in standard industrial environments. They use forced air cooling with integrated fans and are available in various protection degrees, typically IP20 or higher with options. The lineup includes:
- Line Connection Modules: Provide the interface to the mains supply, including main switch, fuses, and contactor.
- Basic Line Modules: 6-pulse or 12-pulse diode rectifiers for non-regenerative applications.
- Active Line Modules: IGBT-based rectifiers with energy recovery and sinusoidal input current.
- Motor Modules: Inverters in booksize or chassis format for single or multi-axis drives.
- Active Filter Cabinets: For harmonic mitigation and reactive power compensation.
Liquid-Cooled Cabinet Units
Liquid-cooled units offer higher power density and are suitable for harsh environments or where heat dissipation is a concern. They use a closed-loop cooling circuit with water or water-glycol mixture. The same functional modules are available as in air-cooled, but with liquid cooling plates. This design reduces cabinet size and allows operation in ambient temperatures up to 40°C without derating.
System Components for SINAMICS S120 Cabinets
To ensure reliable operation and compliance with EMC and power quality standards, a range of system components can be integrated into the cabinet lineup:
| Component | Function | Typical Location |
|---|---|---|
| Line Filter | Reduces conducted emissions, meets EMC Category C2/C3 | Mains input |
| Line Reactor | Limits current peaks, protects rectifier, reduces harmonics | Mains input |
| dv/dt Filter | Limits voltage rate of rise, protects motor insulation | Inverter output |
| Sine-Wave Filter | Converts PWM output to sinusoidal voltage, reduces motor noise | Inverter output |
| Motor Reactor | Compensates cable capacitance, reduces harmonics | Inverter output |
| Braking Module & Resistor | Dissipates regenerative energy when line feedback not available | DC link |
| Safe Brake Adapter (SBA) | Controls motor holding brake with safety integrity | Motor side |
Selection Guidelines
When selecting a SINAMICS S120 cabinet drive system, consider the following steps:
- Define the application requirements: Motor power, speed range, control mode (V/f, vector, servo), and environmental conditions.
- Choose the line connection: Decide between basic (diode) or active (IGBT) rectifier based on need for regeneration and harmonic limits.
- Select motor modules: Match inverter current and power to motor, considering overload capability.
- Add system components: Include line filters, reactors, dv/dt or sine-wave filters as needed for EMC and motor protection.
- Consider cooling method: Air-cooled for standard, liquid-cooled for high power or harsh environments.
- Verify cabinet integration: Ensure all units fit within the available space and comply with local regulations.
Typical Application Examples
SINAMICS S120 cabinet drives are used across various industries:
- Metals: Rolling mills, coilers, shears – high dynamic performance with active rectifiers.
- Mining: Conveyors, crushers, mills – robust design with high overload capability.
- Oil & Gas: Pumps, compressors, extruders – often liquid-cooled for hazardous areas.
- Marine: Propulsion, thrusters, winches – compact liquid-cooled cabinets.
- Test Benches: Dynamometers, load simulators – precise torque control with energy recovery.
Pro Tip: Always check the latest technical documentation for derating factors at high altitudes or temperatures. For long motor cables, a dv/dt filter or sine-wave filter is recommended to prevent insulation stress.
Power Electronics Components Inside
The heart of the S120 cabinet drives lies in advanced power electronics. Key components include:
- IGBT modules: High-speed switching devices for inverters and active rectifiers.
- Thyristors: Used in some rectifier designs for controlled pre-charging.
- Current transformers: For precise current measurement and control.
- DC link capacitors: Provide energy storage and voltage smoothing.
- Fuses and circuit breakers: Protect against overcurrent and short circuits.
Integration with Automation Systems
SINAMICS S120 seamlessly integrates with higher-level automation systems via PROFINET or PROFIBUS. The built-in web server and SINAMICS Startdrive commissioning tool simplify setup and diagnostics. For complex motion control, the integrated SINAMICS S120 drive control chart (DCC) allows programming of custom functions.
Maintenance and Serviceability
Cabinet units are designed for easy maintenance. Front access allows quick replacement of power blocks, fans, and control boards. The modular design means individual modules can be swapped without dismantling the entire cabinet. Regular maintenance includes checking air filters, cooling liquid levels, and tightening electrical connections.
Note: Always follow safety procedures when working on drive cabinets. Allow at least 5 minutes for DC link capacitors to discharge after power-off.
By understanding the available cabinet units and system components, engineers can design a SINAMICS S120 drive system that meets exact application needs while ensuring reliability, efficiency, and compliance with international standards.
