Power Supply Assembly
USA MAV500/MKVI Service Manual
5-8
28-00486-00
This document contains confidential information which is proprietary to ATI. It may not be disclosed to any unauthorized parties,
and it may not be copied. All rights reserved.
© Copyright (ATI) Aristocrat Technologies, Inc. 2002.
Overcurrent Protection
Generic Output 24 V
- The output is limited to current in the range 17.1 A to 22 A.
The response time for the overcurrent circuit is between 20 and 150 ms.
The power will recover if the overcurrent duration is shorter than the recovery time.
If the overcurrent duration is longer than the recovery time, the power supply shuts
down and has to be switched off/on for 1-3 seconds to recover. During shutdown
state, the output 24 voltage is less than 1 V DC.
Current limits are stated for no load condition in the fluoro 24 V output. Generic
output protection includes a 2 A current margin dedicated to the fluoro lamps.
Therefore, the current limits can be reduced by up to 2 A depending on the fluoro
load.
Fluoro Output 24 V
-
The output is limited to a current exceeding 2 A. The output
will recover when the overcurrent is removed.
Output 12 V
- The output is limited to a current in the range 3.1-7 A. The power
will recover when the overcurrent is removed. The response time for the overcurrent
circuit is set to allow the fluoro drives to function correctly. During current limit
status, the output voltage is less than 1 V and current is limited to 2 A maximum.
Overvoltage Protection
All peripherals connected to the 24 V output rail are protected against an accidental
increase of the output voltage. When the voltage rises above 28
±
1 V, the entire
power supply will shut down.
Inrush Current
Some peripherals exhibit significant inrush current when first powered. The power
supply copes with these temporary transients and remains stable. Maximum steady-
state current drawn from the 24 V output is 14.45 A. If a Westrex printer is fitted, it
causes an additional current spike that increases the maximum current to 17 A. The
steady-state current limitation for the output is 17.1 A. Therefore, the off-line
converter is capable of handling the current demands of normal machine operation.
5.3.3 Control Signals
Low-Power Mode Signal
This signal is generated by the Main Board and is used to switch the machine to low-
power mode. This feature is not used in this machine.
Power Fail Signal
The power fail signal provides a warning to the system of imminent mains failure.
The power supply is designed such that one full missing period of mains (50 Hz or
60 Hz) cannot have any effect on the correct operation of the power supply assembly.
The PFAIL signal is generated by the power converter PCBA when the input mains
