Truck alternators convert the mechanical energy from the crankshaft into electric current. These devices are required for charging batteries that power electrical equipment of vehicles.

Kinds of alternators for trucks

Depending on the design, components are divided into the following groups:

• Brushed. They are usually compact and lightweight. It is recommended to dismantle the device once a year to check the state of brushes and replace them if necessary.
• Brushless. Their advantages are reliability and durability. They need servicing before summer and winter.

The devices shown in catalogues also differ from each other by the following parameters:

• Voltage. It may be 24 or 28 V. In car alternators, it is usually 12 V.
• Current rate. It may reach 55 or 100 A.
• Power and dimensions. Trucks are fitted with larger and heavier alternators than passenger cars.
• Location of the cooling impeller. It may be located on the shaft close to the front cover of the housing, or inside the part. In the second case, the impeller is placed in front of the rotor, or on the tip.
• Material of the impeller. Manufacturers often use plastic or metal.
• Pulley design. It may be dual for two V-belts, or single for poly-V belt.

Malfunctions and reasons thereto

Main component failures include, for example, cracking of the pulley due to normal wear, or incorrect installation. If the device has brushes, they can wear off over time. Besides, moisture may sometimes cause short-circuiting of the diode bridge. In such cases, one should contact a service station: the specialists will decide on replacement of these components individually, or the whole assembly. The latter is most often recommended when the inner winding is damaged, which happens due to a short circuit in the vehicle electrical system.

How to detect faults

Truck alternators do not have a clearly defined service life. It should be diagnosed using a special stand; diagnostics should be trusted to professionals. You can also check the unit yourself with a voltmeter. Set engine speed to 3,000 RPM, engage wiper blades, heater and main beam lights, then measure the voltage at the battery terminals. Deviation from the normal value usually indicates the need of repair.

AUTODOC: convenient shopping online

At our online shop, you can buy an alternator that will ensure uninterrupted power supply for your truck. Place your online order today, and we will promptly ship your purchase. Please check whether a promotion applies to your purchase. You may save extra! AUTODOC is always prompt and inexpensive shopping.