IT appears, with a lot of questions ???????? The only difference between
a T-2 and T-3 is the HV power supply module.
THE ABOVE FACTS MAYBE CORRECT ???????????
however you cannot put a 27.5V DC HV power supply in a T-2 Chassis,
there are guide pins, that are in different places, on the 27.5V and the 3 phase supplies.
it won't work, Now that leads to the question is there some other differences ??
you CANNOT plug a T-3 into a working T-2 system, and Visa Versa
page 21 Fig 818, shows the T-2 3 phase Hi Voltage
module,
page 22 shows the T-3 single phase Hi Voltage module.
Power requirements as stated in the
Collins sales literature.
This is not totally incorrect, its just totally
confusing ! read below
The confusion is where you measure the voltage.
note the ""line to line""
The reference above, as to the 618T-2
requiring 208VAC, 3 phase 400 Hz is
incorrect .
The T-2 requires 115VAC 3 Phase, 400Hz
power, & 27.5VDC
There is no 208V power native to
commercial jet aircraft,
only 115VAC single and 3 phase. The placard on
618T-2 also
calls out 115V power req. (you also need 27.5VDC for the
RX)
The Collins sales literature references
208V 400CPS 3 phase. In actuality, and as discussed, you’re feeding the
set 115V 400CPS 3 phase from the aircrafts electrical buss, a rotary
generator, or an inverter. The power source isn’t 208V, it’s 115V.
ONLY when you measure across (2) of the phases do you get 208V. This is
confusing to most folks. 115V 400CPS 3 phase dynamotors are more common
that you’d think. Aside from the noise (I’ll call that “character”),
the rotary converter is the simplest way to power a T-2.