alternator magnet test

If a wrench doesn't get pulled into the back of the alternator it means its no good......why?is there any other reason this isn't magnetized?

Don't think that's correct. Alternator generates alternating current then rectifies through diodes.

The back of the alternator (stator shaft) becomes magnetic when the fields are energized-in other words when the alternator is charging

No juice from the regulator = no magetism = no charge.

If I remember correctly.. if the alternator is good it will cause a magnetic field regardless of the voltage regulators condition. That's how we use to trouble shoot a bad alt. or reg.

Always used a meter.

Didn't realize the stator shaft poles when charging.

If it pulls, it means everything is working. If it doesn't, there is a problem, but it doesn't tell you where. Could be alternator, regulator, field wiring or B+. Just a quick Good/No good check.

I never heard of the test of if its magnetic its good.. you
have to energize the field to create the field... I always
use to try a full field test first at the regulator.. if it
works then change the reg.... a vom can test a lot of things

Try putting a screwdriver blade to the back of any alternator. It will always pull down on a working charging system. This is old school I learned from my first boss when I was in the gas stations and regular gas was still available (am I showing my age a little?).

Keep in mind...
That an alternator may still have some output but be below spec...
Put a voltmeter on it, should have 13.5-14.5V output. If U dont have a voltmeter, check with Harbor Freight they have a give-away one or sells for $5..

Just my $0.02...