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 »
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 »
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 »
