Toshiba VP 300, Installation Instructions Manual

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Power Supply Unit (PSU)
The power supply unit (PSU) is a plug-in unit and is installed in slot A15. Three nominal input
voltages are available for the PSU:
120 VAC
240 VAC
–48VDC
A PSU of the proper input voltage must be used. The system input voltage is displayed on the power
line filter at the rear of the cabinet. The PSU may not be installed or removed with the circuit breaker
in the ON position.
Refer to INSTALLATION, Installation Requirements, for instructions for installing a VP 300 powered
by a –48 VDC PSU.
Refer to MAINTENANCE, Power Supply Unit section, in this manual for instructions on removing
and installing a PSU.
The PSU provides six regulated DC voltages. The voltages are shown in Table 1-2.
The PSU provides the system power fail signal. This signal is activated if the system input voltage
drops out of operational range. The power fail signal interrupts the CPU as a warning of loss of
primary power, allowing controlled shutdown of the VP 300.
The PSU provides the system reset signal. This signal is activated at power up and resets all boards in
the system. The PSU provides a protective circuit breaker for primary power. This circuit breaker also
acts as the system power switch. The circuit breaker is tripped for primary overcurrent, power supply
overtemperature, and secondary overvoltage.
The +5V is sensed at the center of the Shelf A Motherboard. The +12VM is sensed at the SCSI
Motherboard B and SCSI Motherboard C. Each regulated voltage of the PSU includes overvoltage and
overcurrent. The PSU includes overtemperature protection. In the case of an overtemperature
occurrence, the circuit breaker opens.
Toshiba VP Systems Release 7.1 July, 1994
HARDWARE
1-11
Name Nominal Voltage Function
Table 1-2 Power Supply Unit DC Voltages
Digital logic power
Analog circuit power
Fan and disk drive motor power
Analog circuit power
Analog circuit power
Analog circuit power
5V
5V
12V
12V
–5V
–12V
+5V
+5VC
+12VM
+12VC
–12VC
–5VC