Alternator

I have an alternator from an R22 helicopter and cant tell if it has an internal regulator?

It started life as a Prestolite alternator, would anyone here know how i could tell if it has an internal regulator?

no plate on it.

Alternator shop

Take it by an alternator repair shop. They would be able to test it and tell you.

An externally regulated alt will have a B lead (power) a Neg lead and a Field lead. Most modern internally regulated Alt's only have a power lead and possibly a ground lead. However, some older internally regulated Alt's also had a field lead.

If it has no filed lead, it is internal. If it has one it probably is external, but maybe not. I unfortunately have no experience with the prestolite Alt's, only general automotive.

Larry

Thanks

thanks for the help. It appears to be an internally regulated Prestolite with two field attach, field 1 and field 2. I am given to understand that one is grounded and the other of course goes to the Alt. switch on the panel.

Any other opinions on this greatly accepted.