ST heads roation direction

[theboss]

Do all ST heads spin CCW or it varies among manufacturers??
Is it must to spin them in the marked rotation direction or like automotive alternators, they are direction independent..

[Stan]

I'll let someone who actually owns one jump in here but I asked the same question myself last year when considering buying one and was told they rotate in either direction. 
Stan

[Doug]

electrical no difference, clock wise or anti-clock wise ....

Some brush holders are designed to go only one direction but I don't believe this is the case. In a few weeks I'll have my chance to inpect a 12 kw unit that has CSA aproval and a 1 year warrenty. I'll post pictures and get close ups of the brush holder...

Doug

[ZackaryMac]

Car alternators will produce power in either direction, however the fan on most are meant to operate in one direction only. The fan is the small bladed thing behind the pulley. Most are angled in one direction, and are designed to pull air in through the side opposite the pulley and out, to cool the diode pack and regulator - on unit with built-in regulators, GM-style. Fans with non-angled blades will pull from either rotation direction.
 I melted some diodes when I loaded a alternator on a generator at home this way. Confused, I asked the local Starter/alternator Guru, and he told me all this. My fan was turning the wrong way, not cooling the back side properly. The alternator was working hard, but not over-loading.

Didn't mean to butt in this thread, but I did think it was important enough to mention.

[theboss]

so if i take care of cooling fan.. i can spin ST head in either direction... The fans used in most alternators are blower type with 180deg fins..they can spin in either direction creating equal airflow

[ronmar]

I have heard that they can be spun either way, and I would agree with this.  The fan impellar on my ST-5 has straight vanes and will move the same ammount of air from the brush end thru to the driven end regardless of which way it is spun.  The brush holders appear to not care which direction the slip rings below them are traveling.  One set is mounted one way and the other set is mounted the other way off the mounting bars.