A combined microwave oven and extractor hood unit

摘要

A combined microwave oven and extractor hood unit has a variable speed dc motor (30) driving an extractor fan (63). The speed of the motor (30) is controlled by a switch (24) which controls the duty cycle of the current supply to the motor (30). In an embodiment, a step change in speed can be obtained by adding an extra smoothing capacitor (22a) to the dc power supply for the motor thereby reducing the ripple voltage and increasing the average current drawn by the motor (30). <IMAGE>