HDACF series provides simultaneous flashing, alternate flashing or both. It will operate one, two or three strobe lightheads. Operating the wing tip strobes in the alternating mode will provide an accumulated 42 joules of power to each light. When in the simultaneous mode, the accumulated power to each light is 21 joules. In the three light mode, the wing tips will flash simultaneous at an accumulated 21 joules each, they alternate with a third light operating at an accumulated 42 joules. On the trigger selector outlet, a switch mounted in place of the jumper will allow wing tip outlets 2 & 3 to be turned off, while the tail outlet 1 will remain on. This function is commonly used when the third light is for ground operations. This power supply will operate from 10 to 30 VDC.
What is the difference between this unit and 01-0770028-05?
There is no difference since they are the same part. The Whelen model number for our part number 11-16218 is 01-0770028-05
For a two strobe aircraft, do I connect strobes to numbers 1 & 2, leaving 3 empty?
Per the supplier: Any 2 outputs can be used depending how you want them to flash.
I am replacing my original whelen power supply A413A-HDA-DF-14 (p/n 01-0266049-40C) with this newer unit (p/n 11-16218). My concern is the mounting base screw hole alignment. Does the mount base hole pattern remain consistent when changing from an older unit (1985 era) to this newer unit?
Per the supplier: Yes, it is the same and is backwards compatible.