old scotts 8hp welder low weld power any suggestions?

Date 06-04-2008 04:42

just picked up an old scotts welder dial goes up to 135 amps but with the 8hp briggs screaming i cannot run a constant bead it keeps arcing on and off with only 3/32 rod. this has the alternator type unit in it but i was wondering if there is something i can clean or change to get it up to speed. it's light and i like weird old stuff so i would like to hear any suggestions you guys have.

By DaveBoyer (*****)

Date 06-04-2008 05:06

Does this unit have what looks like a car alternator? I would check the brushes and all the electrical connections first. Is it AC or DC? If DC some of the diodes may be breaking down. And to state the obvious, if it is belt driven, be sure the belt is tight. Can You post pictures of the unit?

By donutty (*)

Date 06-04-2008 13:23

yes it looks just like a car altenator. not sure what the diodes look like and not sure where the brushes are? how do i post pictures?
appreciate the help!

By DaveBoyer (*****)

Date 06-05-2008 04:35

The brushes will be inside the alternator on the end oposite the input shaft. You will probably have to take the alternator apart to get to them. They must be free to slide in the holder and long enough to make good contact with the copper slip rings on the rotor [part that turns].

If it is an AC output machine it will not have diodes. If it is a DC output they will be mounted inside the case, same end as the brushes. There will probably be 6 of them mounted in a heat sink, or at least where they get incoming air flow. They are usually round with 1 wire each. Sometimes a blown one will have an obvious problem, other times not.

The biggest difference between this and a 24 volt alternator is the voltage regulator, it is designed specificly for a welder. Hehr Powerline in Texas and few other companies made welder alternators like this.