Operation Manual -
PoWerMaster®
2400 – 30 - 90 kVA
For GPUs with 28 VDC Active Rectifier Unit
Document no. 578.650BB
Page 79 of 91
Input Contactor (Q3):
The 400 Hz input power to the ARU is supplied and controlled via Q3.
Power Supply (G20):
24 VDC / 10 A (Factory adjustment = 25 Volt) regulated control voltage
is supplied from the Power
Supply G20. This module has a wide input range (340-575 VAC). It is supplied via the capacitor
module and pre-fused from the 3-phase circuit breaker Q4 (shared with G1) and located in 400 Hz part.
Refer to Figure 15.0.1.for location layout.
ARU Transformers (T20):
The ARU transformers steps down the 3 phased 400 Hz voltage (3 x 200 Vac) to an appropriate level
for obtaining 28 VDC at the output.
ARU Rectifier (PM20):
The output voltage is kept at 28 VDC by using thyristors, regardless of the input voltage level and the
load.
ARU Board (A20):
The ARU Board interfaces with the processor board and the rest of the 28 VDC unit.
•
Supplied from G20 (X2)
•
Connection to ARU control input on A2 (X1)
•
Control of thyristors.
•
Measures the output voltage.
•
Interface for heatsink thermostat (X5)
•
Input for current transformer T20 (X6)
Resistor (R20):
The discharge resistor R20 is part of the output filter stage and discharges the capacitor C20, when the
unit is turned off.
Filter Capacitors (C20)
The output filter capacitors are also part of the output filter stage and secures that the AC ripple is kept
to a minimum, less than 2% at the output.
Fan (M20)
The fan M20 is part of the total forced cooling of the unit, the primary task for the fan is to cool down
the rectifier module. The air is drawn in via the filter grill on the left hand side of the base module. The
ARU transformers are cooled by the fans located in the 400 Hz part.
