Direct Electricity Feeding from Alternator to Motor

Too many not quite totally related questions here....

You can supply the load without any battery being connected to that part, even though there may be a battery to start the engine.

An increase in load will affect the generator rpm momentarily, but the generator rpm will recover depending on the governor scheme (if fuel supply is sufficient).

There should already be a governor (or equivanlent), without having to add one.

You don't need a battery at all.
I expect most small battery generators start with a pull cord.
Dell

Of course it's possible. Why do it, though?

I think you will get better operating characteristics with a battery. It will help smooth out the power demand, and put less momentary load on your alternator/Engine, which would prolong life.

What is your equipment - a regular commercial generator providing a substitute for AC mains, or a vehicle alternator with rectifier normally used for battery charging? If the former, then no great problem if the load is within the generator's rating. If the latter you will be using a DC motor and a battery is needed.

You might need a battery to energise the alternator to start up, depends on the type of alternator.

The engine should have a governer as mentioned before so it will compesnate for load changes.

Most alternators need power to run field or armature depending on how it's designed.

In addition to all the other considerations there is another reason to use a battery if this is an automobile engine driving your generator. The battery provides a temporary load should your output load fail, or should a momentary open occur for any reason (Shorts to the load would still be catastrophic, but that would be true anyway. And you WILL fuse the circuits, right). In the event of an open circuit on the output of a generator, even if only momentary (spikes in the system without a smoothing cap might also do it), you'll almost certainly blow the output drive on your generator. The only question is which part will fail, and in which direction. Automobile generators are in fact three phase alternators, with a simple diode rectifier built in. Some use a bridge, others just a full-wave rectifier. In either case, a momentary open develops unstablilized (read as "very high") voltages across the output, and almost always blows the output. In my experience in auto repair, usually at least one, sometimes all, of the rectifiers blow. If they open, you suddenly have NO output. If they short, you suddenly have a nearly pure, 3-phase AC sine-wave across the output, and you cease to drive a DC motor, or charge a battery. I don't know what AC on a DC motor would do, but I suspect it would let the smoke out.

Having a battery across the output to sustain a load on the generator won't eliminate the possibility of blowing the rectifiers, but it will certainly limit it. I don't remember seeing any shorted rectifiers in 35+ years working on my own cars that didn't come from an open on the output while the engine was running, and the generator generating.

Of course, a large resistor can do the same job, but why waste the power as heat? If it's cost of a battery, at least use the heat from a resistor to keep your coffee hot.

Let's cover all the basis here

Is this an automotive alternator or a genset alternator?

What type of motor are you trying to run?

What type of IC engine is this?

Describe your objective in more detail.

Thank you- the problem is solved already

Gr8! Please let us in on the answer. What kind of equipment is it and what was the solution?

An alernator can only develop a minimal amount of a/c voltage with out the rectifier. Although these have a 3-phase a/c output, the current output is not the same as if the rectifier is in place. Alternators are designed for DC current output with a max of, on average, 130 amps @ 14Vd/c output. The only way to get a/c current output from an alternator is to use inverters to convert the d/c to a/c, which is very costly no matter how you look at it and try. And trying to use an automotive alternator to create a power source, it takes an inverter to power an a/c motor to drive the d/c power source. I have been working and developing such a design for more than 5 years myself. You can get can only a limited amount of power at this stage. There is not enough a/c output to drive a motor with out having to incorporate the usage of a transformer to booste the output, which in-turn will decrease your actual current output.

And if you are feeding a d/c motor, and its power demand is more than 14Vd/c, you will need to develope into the equation the use of a transformer to boost the output of the alternator, then your rectifier will need to be capable of converting the present a/c to d/c voltage output. And you will be back at the drawing board reinventing a new wheel.

So what is the size of your motor you are trying to feed and run?

Maximo

And if it is more then 1 Hp 1-phase 115VA/c current, which is 60Amps according the NEC codes, you need a very expensive inverter to run this motor. And the largest a/c motor 1-phase you could run effectively is only 2Hp @ 100Amps demand factor.