4.2 SECTION FOUR - COMPONENT DESCRIPTION AND SPECIFICATION
4.1.2. Circuit Description
The power supply consists of four functional blocks:
• High voltage rectification and filtering
• Low voltage control power supply
• Shunt regulator circuit
• Monitoring and fault logic circuits
Figure 4-2 is a block diagram of the 160 Power Supply.
LED
#
LED
Color
Label Condition Indicated
1
Green BUS ACTIVE Greater than 30 VDC is present on the
high voltage DC bus.
2
Green LOGIC VOLTAGE OK The + 15, - 15, and + 5 VDC are
present.
3
Red REGEN FUSE BLOWN The fuse protecting the regen resistor
has opened.
4
Red THERMAL FAULT Baseplate over temperature
5
Red DC BUS OVER VOLTAGE DC Bus has exceeded 400 VDC.
6
Yellow REGEN ACTIVE The regen circuit is active because the
bus voltage exceeds the regen cut-in
threshold or a-c power has been lost and
a fast bus discharge is occurring.
7
Red LOSS OF PHASE Phase loss or power loss on incoming
AC mains.
TABLE 4-1. 160 POWER SUPPLY STATUS INDICATORS
4.1.2.1. High Voltage Rectification and Filtering
The a-c mains input is rectified by a three phase diode bridge and filtered by a large bank
of electrolytic capacitors to generate a nominal 300 VDC supply at
25 amps. This high power 300 VDC supply is unregulated and will vary in direct proportion
with the a-c mains input.
4.1.2.2. Low Voltage Control Power Supply
Control power for the logic circuits is generated by a fly back current mode converter.
There is no isolation from the a-c mains provided by this supply.
