Operator`s manual

Pg. 16 Vicor 800-735-6200 Westcor Division 408-522-5280 Applications Engineering 978-749-3524 or -3525 Rev. 1/99
3 Phase MegaPAC Owner’s Manual
Mechanical Considerations
The 3 Phase MegaPAC can be mounted on any of four surfaces using standard 8-32/M4 screws. The chassis comes
with four mounting points on each surface; maximum allowable torque is 20 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 3 Phase 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 3 Phase MegaPAC. The fan moves
approximately 30 CFM of air.
Avoid excessive bending of output power cables after they are connected to the 3 Phase MegaPAC. For high-cur-
rent outputs, use cable ties to support heavy cables in order to minimize mechanical stress on output studs. Be care-
ful not to short-out to neighboring output studs. The 3 Phase MegaPAC is supplied with serrated, flanged hex-nuts
on all output studs, so Loc-tite® or lock washers are not required. The maximum torque recommended 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
• Do not leave ConverterPAC Sense lines open. Always terminate them locally or at the load. Use twisted
pair 22-24 AWG wire.
• Always fill all output slots of the MegaPAC. If a slot is not filled with a ConverterPAC, it should be
filled with an airblock. Failure to do so can result in overheating and damage to the power supply.
• Do not unplug ConverterPACs while input power is applied. They are not designed for hot-plug
applications.
• Do not restrict airflow to the unit. The cooling fan draws air into the unit and forces it out at the output
power terminals.
• For power expansion use booster ModuPACs. Viewing the unit from the output terminal side, always insert
boosters to the right side of the driver.
• For booster arrays, do not remove busbars.
• Always ensure that output hex-nuts are properly torqued before applying power to supply.
• Run the output (+/–) power cables next to each other to minimize inductance.
• Wait 5 minutes after shutting off power before inserting or removing ConverterPACs.
• Do not attempt to repair or modify the power supply in any manner other than the exchange of ConverterPACs
as described in this manual.
• Insert proper fault protection at power supply input terminals (i.e., a fuse).
• Use proper size wires to avoid overheating and excessive voltage drop.
• Never loosen the inner nut on a ConverterPAC.
• Verify output nuts are tight before powering up.