A huge variety of household appliances contain heating elements. The two basic types are the exposed single-wire element, most often used in hairdryers, fan heaters and toasters, and the metal-sheathed element used in ovens, grills, iron sole plates and immersion heaters.
This type of element is simply an exposed length of conductor which heats up when a current is passed along it due to the resistance properties of wire. As it is an exposed conductor, it must be housed and supported in a way that avoids accidental contact which could cause electric shock or burns. It must also be housed in a way that allows the heat generated to dissipate and do the job intended. For instance, a toaster needs a large aperture in which to place the bread so that it rests near the exposed element for it to function correctly. Read the rest of this entry »
Capacitors used for motor starting may have metal or plastic outer casings with an insulated top with two terminals. Internally the two terminals are connected to two sheets of metal foil with an insulator between. This package of large surface area is rolled into a cylinder which fits into the shell of the capacitor. As the voltage supplied to one terminal is alternating (at 50 times per second), so does the polarity of its connected foil. An opposite movement of electrons is induced in the other foil, even though they are insulated electrically. This causes a delay in the electrical path, and this, in the case of an asynchronous induction motor, gives the outof-phase feed to the start winding. 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 »
Cooker hoods are becoming a standard fitting in many new and refurbished kitchens and are certainly a boon in alleviating cooking smells and the reduction of steam from boiling pans.
Extraction is achieved by means of a motor, usually a shaded-pole type, which drives a normal or barrel fan. Variable speeds are often included for coping with different conditions, and a light to illuminate the hob, independently switched, is another helpful addition. Read the rest of this entry »
Coffee filters have become extremely popular in the United Kingdom in recent years, largely replacing percolators. Although they vary in design, they are fairly straightforward in the way they work.
When water is added to the cold-water compartment, it flows through a hole in the base into a silicone tube containing a non-return valve. The tube feeds water to a metal boiler tube in the metal base plate. This is similar to an iron sole plate and contains a heating element which, when switched on, quickly heats the water in the tube causing it to rise towards the outlet end of the system. The outlet is positioned over a holder containing a filter filled with ground coffee. Hot water is ejected from the tube and filters through the coffee to the jug. This continues as long as there is water in the cold-water compartment and power is supplied to the heater. Read the rest of this entry »
Cooker hoods are becoming a standard fitting in many new and refurbished kitchens and are certainly a boon in alleviating cooking smells and the reduction of steam from boiling pans.
Extraction is achieved by means of a motor, usually a shaded-pole type, which drives a normal or barrel fan. Variable speeds are often included for coping with different conditions, and a light to illuminate the hob, independently switched, is another helpful addition.
When the hood is switched on, the fan sucks air through a filter system to remove grease particles and cooking smells. 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 »
