Can multiple alternators be connected in parallel or in series?
ptwnry asked:
When building a homebuilt Portable Generator using two or more alternators, if I wanted to increase the voltage of the generator so that I could use it to charge a high voltage battery bank could I wire the alternators in series to increase their overall voltage similar to a battery bank? Alternatively, if I just wanted to increase the overall amperage of the generator for faster charging could I connect the alternators together in parallel? I asked the owner of a site about battery bank configurations and he said the alternators would likely need to be isolated or else the negative of one would short out the other. When I followed up to ask if by isolated he meant that there’s just no way to connect multiple alternators together, neither in series nor in parallel, I never got an answer. If anyone knows, I’m all ears.
Salvatore
When building a homebuilt Portable Generator using two or more alternators, if I wanted to increase the voltage of the generator so that I could use it to charge a high voltage battery bank could I wire the alternators in series to increase their overall voltage similar to a battery bank? Alternatively, if I just wanted to increase the overall amperage of the generator for faster charging could I connect the alternators together in parallel? I asked the owner of a site about battery bank configurations and he said the alternators would likely need to be isolated or else the negative of one would short out the other. When I followed up to ask if by isolated he meant that there’s just no way to connect multiple alternators together, neither in series nor in parallel, I never got an answer. If anyone knows, I’m all ears.
Salvatore
March 8th, 2009 at 6:02 pm
Hsiu
ll power generating systems,alternators are operating in parallel.But it must be synchronized to the grid my matching,voltage,frequency and the phase sequence.
I have no experience with alternator in series as voltage can be increased by transformers.
March 10th, 2009 at 11:53 am
Leonida
Connecting alternators in parallel is not all that unusual – in fact, ‘the gird’ consists of a large number of parallel generators. Alternators produce AC, and you must make sure that the voltage sinusoids produced by the paralleled alternators are synchronized. As a practical matter, paralleled alternators will attempt to synchronize all by themselves, but if you start out with them at significantly different angular speeds (frequencies) or angles, the result could be spectacular. To avoid fireworks, you need to have the ability to control the angular speed of whatever is driving the alternators.
Connecting alternators in series is another matter. Theoretically, I suppose it is possible, but I don’t believe that it has ever been done. Its really unnecessary since you can get just about any imaginable voltage by using transformers.
You mention that your objective is to develop enough voltage to charge a battery. Keep in mind that to charge a battery, you must have a DC source, while alternators produce AC. You can always make DC from AC (that requires a device called a ‘rectifier”).
March 10th, 2009 at 5:32 pm
Johnie
Alternators can be connected only in parallel. For this connection, the alternators should have equal terminal voltage, same frequency and phase sequence.Therefore, you can’t increase the voltage of a generator over another unit when they are in parallel. Parallel operation will need an automatic synchronizer which is a costly investment.
March 11th, 2009 at 9:16 pm
Bev
I’m going to assume you are talking about using automotive alternators. If so, the output of these generators is DC because they contain internal diodes to rectify the AC voltage they produce. Therein lies the problem. If you put them in series, you risk exceeding their current rating. If you put them in parallel, you risk exceeding their reverse voltage limits. I suspect your idea would result in cascading failures starting with the diodes and ending with burned coils.