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Description of boards
9.4) SECONDARY POWER UNIT
9.4.1) SECONDARY POWER UNIT G 200 AC- DC (fig. 24)
This unit handles secondary power rectifying and AC switching.
WARNING!: Before commencing the measurements described, make sure the HF board is disconnected from the bus
board!
WARNING!:
should module IGBT break and be replaced, board 15.14.253 (see sect. 9.7 below) must be tested befo-
re reconnecting board 15.14.289 (a faulty IGBT module can break the 15.14.253 board and vice versa)!
Power source / Mode
Test point
Value
OFF
R GA SA
10 k
OFF
R GB SB
10 k
OFF
V A K
+0.3 Vdc
ON / MMA
V GA SA
-13 Vdc
ON / MMA
V GB SB
+13 Vdc
ON / MMA
V 3 1
+0.5 Vdc
ON / MMA
V 1 2
+105 Vdc
ON / MMA
V out*
+52 Vdc
· note: Vout = power source's open circuit voltage OCV
Unless otherwise specified, all measurements sholud be taken with the boards in their slots and connected accordingly
WARNING!
1) Components sensitive to electrostatic discharges.
2) Torque wrench settings:
FASTENING ON HEAT SINK
= MAX 1.5 Nx m / 13 lb x in
BOARD FASTENING
= MAX 1.5 Nx m / 13 lb x in
3) Use layer of thermal grease
