Most labour-saving household appliances contain an electric motor of some description. They are the workhorse of these appliances and most of them are capable of coping with the work loads inflicted upon them. However, some motors, either through poor design or as a result of manufacturers’ cost limitations, are inadequate for the job they are required to do. Adequate or not, at some point it is almost inevitable that they will fail or simply wear out. To delay this, use the appliance with some care and attention, be aware of its limitations and carry out regular inspection and servicing. This will prevent small problems escalating into major ones
Not only do the sizes of motors vary greatly between products, so too do the ways in which they work. To diagnose faults successfully and service or repair appliances, a working knowledge of motors is essential. The following provide a basic introduction to the various types, a description of how they work, the appliances in which each may be found and their particular advantages and drawbacks. Specific problems can be found on individual appliances. Read the rest of this entry »
Unlike the pre-set speed control, variable control allows a greater variation in motor speeds. The motor is a plain AC series-wound brush motor and consequently it is incapable of any variation in speed on its own.
Speed is governed by a separate speed control unit. This unit consists of a printed circuit board with a number of solid-state components, often called the speed module or motor control module. In simple terms, this device interrupts the power supply to the motor at regular intervals. In effect, it pulses the motor. If the pulsing is increased, the motor will run faster and if pulsing is slowed, the motor will run slower. Read the rest of this entry »
