Vicor DC MegaPAC DC-DC Switcher - Manual (Page 13)

DC MegaPAC Operator’s Manual
Rev. 3/04 Vicor 800-735-6200 Mission Power Solutions (760) 631-6846 (phone) or (760) 631-6972 (fax) Pg. 13
Mechanical Considerations
The DC 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” (5,1cm) minimum clearance at both ends of the DC MegaPAC and route all cables so airflow is not
obstructed. The standard unit draws air in at the fan side and exhausts air out the load side. If airflow ducting is
used, avoid sharp turns that could create back pressure. The fan moves approximately 30 CFM of air.
Avoid excessive bending of output power cables after they are connected to the DC MegaPAC. For high-current
inputs and outputs, use cable ties to support heavy cables, minimizing mechanical stress on output studs. Be care-
ful not to short-out to neighboring output studs. The DC 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 appli-
cations.
• 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 ConverterPACs. Viewing the unit from the output terminal side, always
insert boosters to the right side of the driver.
• 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.