Specifications

Configuring and Reconfiguring MegaPACs
Most ConverterPACs of the same length can be inserted into any available slot of a MegaPAC chassis. They can
also be easily added, replaced, or moved by sliding the assemblies in or out of a MegaPAC chassis. (Currently, two
exceptions are the FinPACs which can only be used in the high power chassis and the UniPACs which can only be
used in the 4kW MegaPAC.) For outputs greater than 200 Watts, a driver ModuPAC and one or more booster
ConverterPACs will be used. For outputs greater than 600 Watts, a driver FinPAC and one or more booster
ConverterPACs 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 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
ConverterPACs 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. Bus bars between a driver and booster (s) should never be disconnected. For help in identifying
boosters and drivers, refer to the Part Numbering section on page 8. Please note that total output voltage should
not exceed the converter baseplate-output isolation rating of 400V. For detailed guideline on how outputs should
be placed in series, please refer to the Applications note (Creating high voltage outputs) available on the website at
www.vicorpower.com.
Pg 6 Vicor 800-735-6200 Westcor Division 408-522-5280 Applications Engineering 800-927-9474 Rev. 4/2010
PFC MegaPAC Design Guide
Driver
Bus Bars for Paralleling
Loosen screw to
remove ConverterPAC
Boosters
12
3
4
5
6
7
8
Figure 2. Paralleling ConverterPACs