Product Description:

The RD51.2-4B-015-P-NN-FW is a drive controller built by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. As a dedicated component for variable-speed control of induction motors, it converts fixed mains power into regulated output that matches process demands in automated machinery. By adjusting output frequency and voltage, the device lets production lines, pumps, or conveyors run only as fast as needed, which can reduce energy use and mechanical wear. This operating method also gives the connected motor smoother speed adaptation than direct line operation. Because output is matched to load demand, the controller helps limit unnecessary full-speed running during partial-load process steps.

This controller is rated for 15.0 kW of motor power and accepts a mains range of 380 to 480 V. The power section uses a three-phase AC converter design and tolerates input fluctuations within a ±10% tolerance. Motor magnetization is managed with U/f curve control, which keeps magnetic flux stable across the speed range without closed-loop feedback. Within that supply window, the unit can maintain basic speed control without requiring a separate feedback device for standard applications. The voltage-to-frequency relationship supports predictable torque behavior at low and medium speeds when the motor is correctly matched.

A built-in brake chopper directs regenerated energy to external resistors during rapid deceleration, while an integrated mains filter suppresses conducted emissions at the line terminals. Thermal management is handled by a heat dissipation panel, which supports cabinet mounting without forced airflow on units up to 18.5 kW. The brake chopper is useful when the load returns energy to the drive during stopping or overhauling motion. The integrated filter also helps limit interference fed back to the supply network. The drive belongs to generation 2 and comes without auxiliary function modules or special-purpose options.