A conching mixer for triturating and trowelling chocolate material in a trough has at least two reversible rotors with conching tools which cooperate with the conching surfaces of the trough. At least one motor has a speed control system with a control signal input joined to the output of a measuring set-up for a power parameter of the motor. The motor (M) driving the two rotors (3, 4) in a conching mixer (1) with jacketed walls (2) has in the power supply a dimetal thermoswitch (S) with an adjusting screw (13) for the current input, in series with a resistor R1. Temp. sensors (14, 14') measure the temp. of the chocolate and of the water in the jacket, respectively, as a measure for the motor power output. The motor speed control includes a thyristor (T1) which is controlled by the unit (P) in accordance with signals from the switch (S) via the lines (L). If the change-over switch (SS) is actuated, the unit (P') which is governed by the temp. reading replaces the unit (P). Alternatively a microprocessor compares the motor current with a set value and controls the motor speed.
展开▼
