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Portable home made welder alternator.

Keeping it ........ Exciting

Why build when you can buy?
Choosing the right engine
Choosing an alternator based on your engine
Keeping it ........ Exciting
The sum of all the parts. Hooking it all up.
Balancing it all out
Putting the welder to use
Injury and or death
Credit where credit is due.

Keeping it exciting. 
How to energize the field of your Welder alternator.

A steady field voltage is required to force an alternator up to the rquired 60-90 vdc for striking a good arc. 
It's  better if your engine has a built in charging system.  Lots better.  Spend up to an extra $100.   It makes the job sooo much easier and is more compact,  The field can be excited from the charging system without an extenal extra generator,
A battery can provide this steady voltage for quick jobs.  I prefer an autonomus always capable system such as useing a permanent magnet DC motor to act a generator.  Stick with something designed to run constantly.  An Ametek or any other DC motor capable of providing 4 amps at 12vdc will sufficiently energize the field.  Wind power sites list the voltages and rpms for many permanent magnet motors,  You could also guestimate by looking at the motors specs and then plan on turning it around 20% faster to achieve the voltage it would ordinarily consume then calculate your pulley size based on this.  I used a permanent magnet alternator off a Kubota diesel because it was self energizing and at the time free.  I rectified the output to provide half wave DC (less power to the alternators field)....... vice fullwave (more power to the alternators field).  This built in inefficiency reduces the alternators output and approximately matches it to the available engine power. 









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