Product Description:

The MDC9.20B/MMA-0 is a permanent-magnet DC motor built by Bosch Rexroth Indramat within the MDC DC Motors series. In automation systems it functions as a torque source for feed axes, conveyors, and other motion stages that require stable speed regulation from a dedicated drive. The motor converts regulated DC bus energy into mechanical rotation through its six-pole magnetic circuit, delivering continuous rotary power for industrial positioning and transport tasks.

Electrical parameters set its continuous operating envelope. An armature inductance of 0.90 mH limits current ripple from the drive so commutation remains smooth at variable load. The low armature resistance of 0.150 Ω keeps conduction losses modest and helps the winding accept a nominal continuous current of 33 A. Under that current, the motor produces a nominal continuous torque of 18 Nm, which is adequate for mid-frame belt or screw mechanisms. The insulation system tolerates a maximum peak voltage of 230 V, letting standard 200–220 V supplies operate the motor without overstressing the winding.

Transient and thermal figures affect system sizing. During rapid acceleration, the drive may deliver a peak pulse current of 250 A, allowing high short-term torque without demagnetizing the rotor. Each ampere produces torque in proportion to the torque constant of 0.76 Nm/A, while the generated back EMF rises in proportion to the voltage constant of 79.6 V/KRPM, information the controller uses to predict speed. The rotor reaches 63% of its final speed in 11 ms, revealing a mechanical time constant suited to fast indexing. Heat leaves the totally enclosed, non-ventilated frame slowly, so the winding temperature follows the longer thermal time constant of 60 min, which permits intermittent overloads before steady-state heating is reached. Operation is specified for ambient temperatures up to 45 °C, and the A-side connector orientation simplifies cable routing inside compact cabinets while the six-pole design improves torque density at low speeds.