Question for those who know about alternators.
The AeroSport engine that I have was supplied at my request with an internally regulated 40 amp LAMAR alternator.
How do I make provision for overvoltage protection of an internally regulated alternator?
The AeroElectric Connection that I have (circa 2005) figure Z-24 describes a "crowbar" protection, but cautions that it only be used with an externally regulated alternator:
"Figure Z-24 used to suggest a means by which alternators having internal regulation could be safely and economically applied to aircraft. Recent discoveries and discussions have raised questions about this philosophy...all suggestions for using internally regulated alternators have been removed from the Z-figures."
The Vertical Power installation guide compares internally/externally regulated alternators and suggests that an internally regulated alternator may have failure modes in which an overvoltage event will not be controllable by removing power from the field wire (which is how the VP-X controls overvoltage).
So, it seems that neither a crowbar system (AeroElectric) nor a field wire power system (VP-X) is assured to work with all failure modes.
The PlanePower alternator seems to have solved the problem. LAMAR has not responded to questions that I twice sent to them over the last few weeks - a fact that would influence my decision to choose their product the next time.
So:
How does one deal with overvoltage protection of an internally regulated alternator? Is there a supplier that offers a solution that works?
Bill Brooks
Ottawa, ON
RV-6A finishing kit
The AeroSport engine that I have was supplied at my request with an internally regulated 40 amp LAMAR alternator.
How do I make provision for overvoltage protection of an internally regulated alternator?
The AeroElectric Connection that I have (circa 2005) figure Z-24 describes a "crowbar" protection, but cautions that it only be used with an externally regulated alternator:
"Figure Z-24 used to suggest a means by which alternators having internal regulation could be safely and economically applied to aircraft. Recent discoveries and discussions have raised questions about this philosophy...all suggestions for using internally regulated alternators have been removed from the Z-figures."
The Vertical Power installation guide compares internally/externally regulated alternators and suggests that an internally regulated alternator may have failure modes in which an overvoltage event will not be controllable by removing power from the field wire (which is how the VP-X controls overvoltage).
So, it seems that neither a crowbar system (AeroElectric) nor a field wire power system (VP-X) is assured to work with all failure modes.
The PlanePower alternator seems to have solved the problem. LAMAR has not responded to questions that I twice sent to them over the last few weeks - a fact that would influence my decision to choose their product the next time.
So:
How does one deal with overvoltage protection of an internally regulated alternator? Is there a supplier that offers a solution that works?
Bill Brooks
Ottawa, ON
RV-6A finishing kit
