Choosing the right alternator is not always easy. There are different brands, sizes, power outputs, connections and features to consider. As a generator manufacturer, we have used many variations of these in our own products. If you need help, talk to us. If we don't know the answer, we will find someone who does.
RE-CONNECTABLE vs DEDICATED WIRING
Re-connectable 12 wire alternators are not as efficient as dedicated wiring versions however they can be used for single and three-phase power. Because they can be wired in so many different ways, they are a bit more expensive and not as efficient.
If you select an alternator with dedicated wiring, it is more efficient and costs less. You must decide what phase and voltage you want before buying it because it can't be changed later.
The engine connection to the alternator in most applications is by direct coupling. The alternator is mounted directly to the engine and the flywheel directly to the alternator coupling disk. The sizes of these are standards in the industry. These are known as single bearing alternators. One end has a bearing to support it while the other end is supported by the engine flywheel and housing.
Double-Bearing alternators have two bearings. One on each end. They have a drive shaft that can accept a pulley and be turned by a belt and other machinery.