[TR] C40 generators

[Randall]

The 19 amp generator was model C39PV/2, part 22258x.  The main housing is
slightly smaller diameter than the later C40 but the mounting points are the
same (making them interchangeable as complete units even though the parts
are different).  ISTR that at least some of the C40s had a step in the
housing but I could be mistaken on that point.  I don't know if it would
apply to all Lucas units, but at least for the Triumph application, the C39
had screw terminals while the C40 had 'Lucar' quick connects.  I don't know
if they were electrically different or not, it may have been just that the
larger armature cooled better.  The C39 will easily put out 22 amps (or
more), but will eventually overheat at that current.

Very early control boxes were RB106/1, but early RB106/2 were also for the
19 amp generator, part number 37182x.  My documentation shows part number
37283x and 37290x for the 22 amp version (which again had Lucar instead of
screw terminals).  Again I'm not certain if there was any electrical
difference, but the "open circuit voltage" specification went up by 0.4
volts.  I grabbed one of each out of the parts bin and they definitely have
the same number of current turns on the regulator relay, but there might be
a change in the number of voltage turns (which are inside a plastic sleeve
and hard to see).

-- Randall