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Mechanical Considerations
The PFC MegaPAC-EL™ and PFC MegaPAC-HPEL™ 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 20lb.in. The maximum penetration is 0.15in [3.8 mm].
When selecting a mounting location and orientation, the unit should be positioned so air flow is
not restricted. Maintain a 2in minimum clearance at both ends of the PFC MegaPAC-EL and PFC
MegaPAC-HPEL 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-EL and PFC MegaPAC-HPEL. The fan
moves approximately 30CFM of air.
Avoid excessive bending of output power cables after they are connected to the PFC MegaPAC-EL
and PFC MegaPAC-HPEL. For high-current outputs, 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-EL and PFC MegaPAC-HPEL 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 recommended on flanged nuts is 45lb.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™ Dos and Don’ts
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For units without Autosense, do not leave ConverterPAC Sense lines open. Always terminate them to
their respective output locally or at the load. Use twisted pair 22-24AWG wire. If ConverterPAC has
Autosense, no local-sense connection is required. See Pages 11 and 12 for more information
on Autosense.
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If needed, use Connector Kit # 19-130040 for the PFC MegaPAC-EL and PFC MegaPAC-HPEL.
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Always fill all output slots of the MegaPAC. If a slot is not filled with a ConverterPAC, it should be
filled with an airblock. Airblocks are plastic assemblies whose main function is to fill up an empty slot.
Any airflow escape from an empty slot significantly degrades thermal performance and can result in
overheating and damage to the power supply.
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Always turn the power supply off before disconnecting input or output wires.
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NEVER disconnect the +Out and –Out load wires while the supply is operating, as disconnecting WILL
cause damage to the power supply.
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Do not unplug ConverterPACs while input power is applied. They are not designed for
hot-plug applications.
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Do not restrict airflow to the unit. The cooling fan draws air into the unit and forces it out at the
output power terminals.
