Centrifuge electric motor and brake - has brake resistor across armature with transistor connection to field coil circuit

摘要

The design offers a braking circuit for centrifuges with constant braking force at high- or low speeds of the motor. The centrifuge is driven by a DC motor with field coil (2) and armature (4) both of which can be connected to relay contacts (1a, 1b) and (1c, 1d) to form a braking circuit. Parallel to the armature (4) brake resistor (5) is the base emitter section of transistor (6). The field coil (6) is connected via the emitter collector section of the transistor (6) with the DC source.