Product Overview and Technical Positioning
The INDRAMAT RAC 2 spindle drive controller is an intelligent digital controller designed specifically for CNC machine tool spindle systems. It is suitable for driving INDRAMAT 2AD series asynchronous spindle motors and 1MB series frameless spindle motors, with a continuous output power range of 30 kW to 52 kW. With its high rigidity, wide speed range, and continuous power output characteristics, this controller performs well in the field of CNC machine tool spindle drive, especially suitable for high-precision machining scenarios.
The RAC 2 controller has an internal position control loop that can independently respond to signals for spindle positioning, with a resolution of up to 1/4000000 revolutions per minute. It supports C-axis operation mode and uses the spindle as a servo axis for high-precision position control, suitable for high-precision processes such as workpiece tool changing and thread machining. The controller can be directly connected to the three-phase power network (3 × 400 V/50 Hz or 3 × 460 V/60 Hz), with built-in main contactor and emergency stop switch, supporting the feedback of braking energy to the grid, and can achieve energy recovery even in emergency stop state.
System structure and functional characteristics
1. Mechanical and Thermal Management Design
The RAC 2 controller adopts a modular structure, with heat sinks and fans integrated inside the housing, supporting three cooling methods:
Air cooling inside the control cabinet: Air is sucked in and discharged from the cabinet;
Control cabinet external air cooling (factory default): exchange of internal and external air through openings on the back of the cabinet;
Hose cooling: Introducing external air through an external hose, suitable for situations where the cabinet back cannot be perforated.
The installation position of the controller is fixed and only allows operation in the orientation shown in Figure 2.3. Its protection level is IP 10 (EN 60529), and it needs to be installed in a control cabinet that meets safety standards to achieve sufficient contact protection. The working environment temperature ranges from+5 ° C to+45 ° C (maximum+55 ° C), with an altitude not exceeding 1000 meters, and a humidity level in accordance with DIN 40040 F.
2. Electrical connection and interface configuration
The electrical connections of RAC 2 are divided into three categories:
Feedback and CNC interface: including motor feedback, spindle feedback, synchronous input, etc;
Power connection: including main power input and motor power output;
Controller specific interface: including main contactor control, monitoring signals, "ready" status output, etc.
All interfaces adopt standardized plug and terminal allocation, and the specific wiring diagram can refer to the document "Electrical Connection Design Guide" (document number 209-0042-4111). The controller also provides multiple speed setting interface options:
Simulated speed setting (± 10 V)
Digital speed setting (16 bit parallel)
SERCOS real-time communication interface
In addition, incremental encoder output, serial interface (for parameter storage and loading), or digital position setting input (16 bit parallel) can be optionally selected to meet the integration requirements of different systems.
AS programming module: parameterization and system adaptation
The AS programming module is the core configuration unit of the RAC 2 system, storing all parameters related to motor matching and application programs. Each spindle drive system is equipped with a pre configured AS module at the factory, which users can use directly without on-site adjustment.
Module features:
Plug and play, supporting quick debugging;
Parameters are divided into two categories: "driver related" and "application related";
Support module replication and backup, facilitating batch device deployment;
Software updates do not affect existing features and maintain backward compatibility.
The front of the module is labeled with a model number, including the type code, motor and controller data, software version, and parameter date. Users can modify application parameters through the front panel keyboard, and the driver parameters are pre-set by INDRAMAT and cannot be changed.

Installation and commissioning specifications
1. Mechanical installation
The controller weighs 121 kg and needs to be installed using lifting equipment. The standard delivery is an external air cooling structure. If it needs to be changed to internal air cooling or hose cooling, structural modification must be carried out before installation:
Remove the cooling shell cover plate;
Remove the lower baffle of the heat sink;
Install the hose flange assembly (if applicable).
The back panel of the control cabinet needs to be perforated according to Figure 2.4, and the attachment M1-RAC 2 installation frame should be used to enhance the structural rigidity, ensuring that the sealing performance reaches IP 54 (inside the cabinet) and IP 24 (fan).
2. Electrical installation
The power cord needs to be twisted and arranged;
The motor grounding must be completed on the controller side;
All D-Sub connections must be tightened;
Before powering on, a power protection cover must be installed.
3. Debugging and operation
The debugging process is universal for all RAC series controllers, and detailed steps can be found in the "Application Description Document" (209-0041-4109). Before powering on, be sure to insert and lock the AS programming module. The system supports fault self diagnosis, displaying error codes on the front panel display screen, and the fault handling guide is also provided in the above document.
Maintenance and Service Support
1. Fault diagnosis and controller replacement
When the controller malfunctions, the drive will stop braking and cut off the power supply. If the controller needs to be replaced, simply move the original AS module to the new unit to restore all parameters and functions. Before maintenance, the main power must be cut off and unexpected restarts must be prevented.
2. Maintenance of cooling system
The cooling air duct must be kept clean to avoid dust accumulation and overheating. If using a cooling device inside the cabinet, attention should be paid to:
Set the cooling temperature to no less than 40 ° C;
Prevent condensation droplets from falling or splashing onto the controller;
The cabinet should be well sealed to prevent humid and hot air from entering.
3. Global Service Network
INDRAMAT has service representative offices in multiple countries including Germany, Italy, the Netherlands, the United Kingdom, the United States, China, and South Korea, providing technical support and maintenance services. The faulty equipment can be returned to the designated repair point with a 'repair card' (see Figure 10.1) attached.
