UOBD
Maintenance in Pretoria

U-OBD South African Supplier of all Diagnostic Scanners and Special; Tools for the Automotive Industry. We are looking forward in assisting you with your automotive needs. Over 20 years experience in the automotive industry, feel free to contact us for recommendation special tools and equipment for your specific needs. All our equipment is sourced from reputable distributors directly ensuring affordable prices and the best quality. If we don't have what you are looking for please tell us and we will do our best to find it for you. We strive to deliver the best service to South Africa's Automotive After Market section to assist with accurate diagnosis and efficient repairs to minimize vehicle down time and to ensure fix right first time to keep your customers happy.

Starter motor Starter motor: Nowadays, the most vehicle engine uses the series winding type Starter motor of which source is battery, for the start motor. Battery Types: The battery used in the most vehicles is the secondary cell (storage battery or galvanic battery) possible to be charged and discharged of which kinds are like the followings. The electrolyte is only used for moving the electrons and not used in the chemical reaction for charging and discharging, so the specific gravity shall not be changed almost. The case is made of the steel sheet coated with nickel or the plastic. Among them, the energy for moving is generated at the explosion stroke only, and this energy is transformed to the flywheel and output through the continuous rotational movement by the inertia force of the flywheel. However, the direction of current is not changed by the brush, so the direction of electromagnetic force is the same with the figure even while the current is flown from the coil A to the coil B. According to the connecting method between the armature coil and the field (yoke) coil, the series winding type, the shunt winding type, and the compound winding type are used for the direct current motor comprising of armature coil, field (yoke) coil, commutator and brush. This type is that the armature coil and the field (yoke) coil are connected in serial. The rotation force of the motor is proportional to the multiplying of the armature current and the strength of the magnetic field. The strength of the magnetic field is decided by the yoke current and the armature current. As the armature current is high, the rotation force will be increased. Therefore, the armature current is reversely proportional to the speed. As shown in the graph, when the speed is low, that is, the load is high, the rotation force is high because of the increased armature current, and so the series winding dc motor is generally used for starting motor. It can be used for the motor of constant speed operation in which the rotation speed is not changed when the load is varied, or for the motor of acceleration or deceleration in which the rotation speed is varied by the yoke current. Like the series winding type, the rotation force is proportional to the multiplying of the armature current and the yoke field strength. However, the strength of the magnetic field can not be changed in this type, so the characteristic graph will be as shown in Fig E. That is, as the armature current is large (the load is high), the rotation force is increased, but the increased ratio is less than that of series winding type. The rotation speed of the motor is proportional to the voltage and reversely proportional to the field yoke strength. Therefore, when the power source is the battery, the voltage is constant and the yoke field is not changed. Consequently, when the armature current is increased, the voltage is lowered little but the rotation speed is almost constant, as shown in figure E. This type is that the armature coil and one field coil are connected in serial and these are connected another field coil in parallel. The pole directions of these two field coils are the same. That is, when the motor is starting, it has large rotating force like the series winding type. After it is started, it has constant rotation speed like the shunt winding type. In this case, the current is only supplied to the armature coil, so if the direction of current is changed then the rotation direction is also changed. The reason is that the pole direction of the ferrite magnet is not changed; however, pole direction of the armature, the electromagnet, can be changed according to the direction of the current.