| 摘要 |
<p>A rotatable drum with an incorporated electric heater (27) and an electric temperature sensor (28) and, outside of the drum, an electric supply (30) for heating the heater and a control circuit for controlling the heating as a function of the measuring signal over the temperature sensor (28), wherein the electric connections with the drum occur over two sliding contacts only, and wherein a diode (29) is provided in the circuit of the sensor (28) thereby to protect the sensor (28) against the voltage of the heating supply (30).</p> |
