All the mentioned generators have the highest continuous speed of 16,000 rpm, the maximum speed of 18,000 rpm is allowed for no more than 15 minutes. The 70 A generator starts charging at 1,150 rpm, the 90 A and 120 A generators – at 1,200 rpm.
The generators are driven by a multi-groove belt from the crankshaft. The pulley mounting bolt is tightened to a torque of 65±5 Nm. The belt tension is automatic, using a spring-loaded roller. All types of generators are mounted at four points and are placed on a separate bracket mounted on the engine crankcase. The bracket can also carry other auxiliary equipment (for example, an oil pump for a power steering or an air conditioning pump, etc.). Amateur intervention in the charging unit is not allowed. For periodic inspection, maintenance, minor repairs, please contact the Skoda service.
When using the charging unit, it is necessary to adhere to certain principles and instructions.
Cars are equipped with alternating current generators, the use of which became possible only as a result of the development of semiconductor technology and the production of diode semiconductor rectifiers based on it. The generator is capable of producing high power in a significant range of revolutions and recharging the battery already at revolutions close to idle speed. A necessary component of the charging unit is a voltage regulator. A current regulator is not needed, since the generator itself limits its current when the specified revolutions are exceeded. The voltage fluctuates depending on the revolutions and this is the reason for the use of a voltage regulator. Diodes pass current only in one direction and thus protect the battery from discharging through the generator to the case. However, diodes also have their own application limits, determined by their physical nature and they can only be loaded within certain temperature and voltage limits, which cannot be exceeded if we do not want to destroy them. In order to fully utilize all the positive aspects of the generator and its high durability with minimal maintenance, it is necessary to adhere to the following recommendations: The negative pole of the battery should always be on the body. This should be especially monitored when using an auxiliary battery (for example, when starting the engine in winter). When the poles are reversed, the semiconductors fail. The generator will not be "excited".
When charging, the battery is disconnected from the vehicle's electrical system. It is better to charge the battery using an external source outside the vehicle.
When repairing any part of the power supply circuit, the battery must be disconnected. Even a short circuit can damage the diodes.
The generator should not operate without a load, which means with the wire disconnected from terminal B. If the connection is poor and the speed increases, the diodes will again be at risk due to excessively high voltage.
During engine operation, the generator must be powered, so operation without a battery must not be allowed.
If the charge indicator light burns out, it must be replaced immediately with a new one, because otherwise the generator will not be excited, which is necessary for operation.
When performing electric arc welding on a vehicle, the generator must be disconnected in the same way as other components (instrument panel, control unit, etc.). Therefore, all welding work must be carried out exclusively at a Skoda service center.
Any repairs (and "checking" of the generator) must be carried out at a Skoda service center.
A malfunction in the charging unit is primarily indicated by the control lamp of the charging indicator, namely:
- when turning the key in the ignition switch the light does not come on;
- the charging indicator light does not go out even when the engine speed increases;
- when the speed increases, the light does not go out, but only the intensity of its glow decreases.
If any of the listed faults are detected, while other energy consumers are operating normally, you should visit a Skoda service center.