All the mains appliances featured here have some kind of mains cable. Problems with the electronic cables of portable appliances are quite common, especially those that are moved around constantly while in use, such as vacuum cleaners and hedge cutters.
The problems can range from a simple break in one or more of the conductors, which would render the appliance open circuit, to the breakdown of the cable’s insulating properties caused by damage, fatigue or neglect, leading to the risk of electric shock or fire. Electronic cables and extension leads must be checked regularly and thoroughly.
There are several different types of flexible electronic cable in two-core and three-core configurations on the appliances shown here. It is important to remember that two-core electronic cable is used only on double insulated appliances; three-core electronic cable is used on all items requiring an earth connection. Read the rest of this entry »
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 »
The information given here also applies to the grills on many cookers. This is a simple way to ascertain if the control is faulty. Short circuit failures on elements may damage regulators in which case, if you are in any doubt, renew it.
The following test is for a single circuit application, that is, a single element. For double regulators, that is, a double element, the same procedure will be required on both single and double operations of the switch. From off position an anticlockwise turn will put into circuit one element (usually the inner), a clockwise turn from the off position will put into circuit both inner and outer. Check that double regulators operate independently on a half turn each. For singles, use ony a full turn. Read the rest of this entry »
The speed control on this type of mixer results from the interaction of mechanical action and electronic control. Two variations of electrical control can be found but each uses the same mechanical action.
Two small spring steel plates are fixed to the cooling fan on the lower end of the armature shaft. They are slightly bowed and joined at either end by a small weight. Only the top plate is secured to the fan and shaft. When the motor rotates, the weights on each end of the joined plates are forced outwards by centrifugal force. As they are formed in a bowed configuration and joined at either end, the outward movement of the weights causes the lower plate to be forced downwards. The degree of movement is proportional to the rotational speed of the armature. This movement is used to actuate a switch on the speed control panel. 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 »
The electric food mixer is truly a labour-saving appliance. Many variations can be found from the simple hand-held type to the large table-top version with additional attachments, such as juice extractor, liquidizer, vegetable peeler, can opener and grinder.
At the heart of all mains powered mixers is a series-wound brush-gear motor. This type of motor is used because of its good power output (up to 3hp on large table-top models) combined with the capacity for variable-speed control. These two advantages make this aversatile appliance. Read the rest of this entry »
The brush roll is supported on bearings at each end so the barrel rotates freely. Types of bearings, barrels and brushes differ from model to model as well as between manufacturers. Some manufacturers supply individual parts for the brush roll, such as brush strips, bearings and barrel; others supply only complete assemblies. The brush roll on some models may have removable brush strips, whereas others may be a solid brush roll of wood or plastic with fixed brushes. A small selection is shown here to highlight the differences. Read the rest of this entry »
The upright style of vacuum cleaner is perhaps the best for large areas of carpet. It is especially good at removing dirt embedded within the pile and pet hairs from the surface, even on sculptured carpets. A drawback with the basic upright cleaner is its difficulty with cleaning stairs. The problem has been overcome with the modern combination of upright and cylinder cleaner. This type may be the best option if you have large areas of fitted carpet and staircases. The motor within the upright cleaner creates the airflow (suction) and drives a rotating brush roll, often called an agitator barrel. Read the rest of this entry »
The domestic vacuum cleaner has been with us now for some 90 years, during which time it has become the most popular labour-saving appliance in the home. The basic principle of operation is quite simple. An electric motor drives fans to create a fast-moving air flow. At one end, a vacuum (suction) of air is created, while at the opposite end the air is exhausted. If the air is moved quickly enough at the inlet end, it will carry with it any debris that enters the airflow. A means of removing the debris from the airflow is required to prevent its redistribution as the air is expelled. Read the rest of this entry »
Cord rewinds are now found on all types of cleaners, from simple hand-operated versions to the fully automatic rewind at the touch of a button. Many auto cord rewind systems use open coil springs and great care should be exercised if a stripdown of these systems is called for. Protection for the eyes is recommended. Goggles afford adequate protection from the spring itself or any item that it may throw out in the event of its slipping from position.
Operation of the cord rewind relies on tensioning of the rewind spring as the cord is pulled out for use. A small brake pad prevents the immediate return of the spring and cord drum to its original position. Read the rest of this entry »
