Vicor 4kW MegaPAC-EL AC-DC Switchers - Manual (Page 5)

UG:108 vicorpower.com Applications Engineering: 800 927.9474 Page 5
Configuring and Reconfiguring MegaPACs
Most ConverterPACs of the same length can be easily added, replaced, or moved
by sliding the assemblies in or out of a MegaPAC chassis. They are driver QPAC
ConverterPACs and can be inserted into any available slot. For outputs greater than
200 Watts, a driver QPAC and one or more booster QPACs will be used. For outputs
greater than 500 Watts, a driver QPAC (XQ) (in the 4kW MegaPAC - EL) and one or more
booster QPAC (XQs) will be used. Arrays of drivers and boosters should be configured so
all boosters are placed in the slots to the immediate right of the driver when looking at
the output end of the MegaPAC.
Prior to removing or installing ConverterPACs, you must remove power from the
MegaPAC and wait 5 minutes. Failure to do so can result in personal injury or
damage to the supply.
Take standard ESD precautions when handling ConverterPACs.
Removing QPAC ConverterPACs
ConverterPACs can be removed by loosening the captive screw at the base. Once
this screw has been loosened, the ConverterPAC will slide out of the chassis. Once a
ConverterPAC has been removed, the empty slot MUST be filled with either another
ConverterPAC or an airblock. If the slot is left empty, it will provide an airflow escape
and cause failure to the power supply.
Installing ConverterPACs as Drivers
ConverterPACs can be installed in empty slots by simply sliding in the new
ConverterPAC and securing the screw at the base. Power and interface connections can
be made after the ConverterPAC has been installed.
Installing Booster ConverterPACs to Increase Output Power
Most ConverterPACs of the same length can be paralleled for more power. Additional
power to an output is obtained by connecting one or more boosters in parallel with a
single driver. The driver can be placed in any open slot. All boosters should be inserted
in the slots to the immediate right of the driver, as viewed from the output end of the
MegaPAC. Figure 2 shows a driver placed in slots #1 and 3 boosters placed in slots # 2 to
4. After inserting the driver and boosters, they are paralleled using bus bars across the
positive and negative output studs. Drivers should not be paralleled with each other. For
the 3 Phase/4kW MegaPAC/ELs (Low Noise), all the driver and booster ConverterPACs
must consist of the Extended Length ConverterPACs. Bus bars between a driver and
booster (s) should never be disconnected. For help in identifying boosters and drivers,
refer to the section on Part Numbering on page 9. Please note that total output voltage
should not exceed the converter baseplate-output isolation rating of 400 V. For detailed
guideline on how outputs should be placed in series, please refer to the Applications
note available on the website at
www.vicorpower.com .
Driver
Bus Bars for Paralleling
Loosen screw to
remove ConverterPAC
Boosters: Slots 2, 3, 4
1 2 3 4 5 6 7 8
L1 L2 L3
9 10
Figure 2.
Paralleling ConverterPACs
End of Life - Not Recommended for New Designs