Specifications

Mechanical Considerations
The PFC MegaPAC can be mounted on any of four surfaces using standard 8-32 or 4mm screws. The chassis comes
with four mounting points on each surface; maximum allowable torque is 5.5 lb-in. The maximum penetration is 0.15
in. (3.8mm).
When selecting a mounting location and orientation, the unit should be positioned so air flow is not restricted.
Maintain a 2" minimum clearance at both ends of the PFC MegaPAC and route all cables so airflow is not obstructed.
The standard unit draws air in at the fan side/AC input side and exhausts air out the load side. If airflow ducting is
used, use caution, as sharp turns could present back pressure to the PFC MegaPAC. The fan moves approximately 30
CFM of air.
Avoid excessive bending of output power cables after they are connected to the PFC MegaPAC . For high-current out-
puts, use cable ties to support heavy cables in order to minimize mechanical stress on output studs. Be careful not to
short-out to neighboring output studs. The PFC MegaPAC units are supplied with serrated, flanged hex-nuts on all
output studs. Therefore, thread locking compounds or lock washers are not required. The maximum torque recom-
mended on flanged nuts is 45 lb-in. Never loosen the inner nut on a ConverterPAC. This nut supports the hardware
inside the ConverterPAC and is factory torqued.
Avoid applications in which the unit is exposed to excessive shock or vibration levels. In such applications, a shock
absorption mounting design is required.
MegaPAC Do’s and Don’ts
• Remote sense should be used:
a) To improve poor output regulation
b) When using older ConverterPACs that do not have the autosense feature.
• NEVER connect the remote sense wires in reverse.To avoid failures, always terminate the +Sense to the +Out
and the -Sense to the -Out
• If needed, compatible connector kits can be ordered separately. Refer to page 23 for additional information
regarding connector kits
• To avoid overheating, NEVER operate the supply with an open output slot. Open slots should always be filled
with a ConverterPAC or a plastic airblock designed for the PFC MegaPAC
• Always turn the power supply OFF before disconnecting any input or output wires. Failure to do so may lead to
an electrical shock hazard and or damage to the power supply
• Do not insert or remove a ConverterPAC while the power supply is running. They are not designed for hot inser-
tion or extraction
• Wait 5 minutes after shutting off the power supply before inserting or removing a ConverterPAC
• Do Not restrict airflow to or from the supply as this can cause overheating damage.
• Booster ConverterPACs are available for power expansion. Refer to page 6 for additional information
• Do Not use boosters as independent outputs. Operating boosters with disconnected bus bars will cause failures
• Before turning on the unit ensure all input and output wire are properly connected and all hex nuts properly tight-
ened
• Keep output wires as short as possible and run the output (+/-) power cables next to each other. Use twisted pair
wiring whenever possible
• Avoid running input and output wiring in close proximity as this may cause noise related problems
• PFC MegaPACs are NOT user serviceable. Please contact our customer service department at 1-800-735-6200 for
repair assistance. Please be advised that attempts to repair or modify the power supply will void the warranty
• A proper fault protection device (fuse or breaker) should be used in series with the input terminals
• Use proper size wires to avoid overheating and excessive voltage drop.
• Never loosen the inner nut on a ConverterPAC.
• FinPAC ConverterPACs can only be used with a high power chassis. A high power chassis is identified by an
“MX” prefix code in the specific model number
• Output voltages over 60Vdc, whether from individual modules or series arrays, are considered as hazardous sec-
ondary outputs under UL 60950. Appropriate care must be taken in design implementation of the supply..
Pg 4 Vicor 800-735-6200 Westcor Division 408-522-5280 Applications Engineering 800-927-9474 Rev. 4/2010
PFC MegaPAC Design Guide