USER GUIDE | UG:108
End of Life - Not Recommended for New Designs
3 Phase MegaPAC-EL
TM
(Low Noise)
4kW MegaPAC-EL
TM
(Low Noise)
AC-DC Switchers
September 2013
®
S
C
US
C
NRTL
Contents
Overview
of Product
Mechanical
Considerations
MegaPAC
Do’s and Don’ts
Technical Description
Configuring and
Reconfiguring
MegaPACs
ConverterPAC
Description
Part Numbering
Quick Install
Instructions
Mechanical Drawings
Interface Connections
Specifications
Current Share Boards
Low Leakage Version
Page
1
2
3
4kW MegaPAC
3 Phase MegaPAC
4
5
Overview
The 3 Phase MegaPAC - EL and 4kW MegaPAC - EL are field-configurable, single or
multiple output switchers, providing up to 2,000 W (3 Phase MegaPAC/EL- Low Noise)
to 4,000 W of output power (4kW MegaPAC/EL-Low Noise). The chassis has 10 slots
and provides up to 20 regulated, fully isolated outputs. It achieves power densities of
3.6 W per cubic inch (3 Phase MegaPAC/EL (Low Noise)) to 6.4 W per cubic inch (4kW
MegaPAC/EL (Low Noise). The dimensions for the 3 Phase MegaPAC/EL (Low Noise)
are 4.9"H x 7.5"W x 15.2"L (124,5mm x 190,5mm x 429,3mm) and the dimensions for
the 4kW MegaPAC/EL (Low Noise) are 4.9"H x 7.5"W x 16.9"L (124,5mm x 190,5mm x
386,1mm). The 4kW MegaPAC/EL (Low Noise) is longer than the 3 Phase MegaPAC/EL
(Low Noise) to accommodate a 2nd fan.
A complete power supply is configured by selecting and inserting up to ten same
length slide-in output assemblies called ConverterPACs. ConverterPACs incorporate
one or two VI-200/VI-J00 and/or MaxiVicor DC to DC converters and are available in
a wide selection of output voltage and power levels. The net result is a power supply
that offers the advantages of a custom supply, but is assembled from standard and
modular building blocks. For detailed information about all ConverterPACs, refer to
the ConverterPAC information sheets. The 4kW MegaPAC-EL (Low Noise) uses VI-200/
VI-J00 and Maxi Vicor DC to DC converters while the 3 Phase MegaPAC-EL (Low Noise)
uses VI-200/VI-J00 Vicor DC to DC converters.
Manufactured at Vicor, the entire family of MegaPAC power supplies is completely
user-configurable. If output requirements change, i.e., more power or a different
output voltage is needed, upgrading is easy: simply unlock a single screw and replace
the slide-in ConverterPAC with another Extended Length ConverterPAC that has the
desired voltage power rating. For additional flexibility, same length ConverterPACs
can be connected in parallel to increase output power (booster ConverterPACs), or in
series for higher voltages (total output voltage should not exceed 400 V). The driver is
to the left of the boosters when looking at the output end of the supply. A user-friendly
interface provides control and output sequencing capability, in addition to useful status
indicators. Please consult our Applications Engineering Department if you have other
special requirements.
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Applications Engineering: 800 927.9474
Page 1
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10
12
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26
29
Standard Features
n
Input: 3Æ 208/240 Vac Wye or Delta, 1Æ 180-264 (47-500Hz) or 260–352 Vdc
n
Power Output:
3 Phase MegaPAC: 2,000 W with 3Æ input; 1,200 W with 1Æ input
4kW MegaPAC: 4,000 W with 3Æ input; 1,500 W with 1Æ input
n
10 slots (upto 20 outputs)
n
Fan cooled (4kW MegaPAC-EL has 2 fans)
n
Full power to 45°C; half power to 65°C
n
Power Factor Correction - passive - to 0.92 PF (3Æ input)
n
Conducted EMI meets EN 55022 Level A
n
AC Power OK and AC Power Fail status signals
n
Output Sequencing and General Shutdown
(Consult Applications Engineering for automatic sequencing circuitry.)
n
Auto Sense capability Refer to page 12 and page 16 for more information on Autosense
n
Overcurrent protection on all outputs
n
Overtemperature limiting (not applicable with VI-J00)
n
Overvoltage protection (not applicable with VI-J00 modules)
n
Size: 3 Phase MegaPAC - EL: 4.9"H x 7.5"W x 15.2"L
(124,5mm x 190,5mm x 429,3mm) Extended chassis
Size: 4kW MegaPAC - EL: 4.9"H x 7.5"W x 16.9"L
(124,5mm x 190,5mm x 386,1mm) Extended chassis
n
Safety Agency Approvals: cURus, cTUVus, CE Mark
Optional Features
n
DC OK status signal
n
Output voltage adjustment range with built-in potentiometer
n
Reversed fan airflow direction
n
Current Share Boards - see page 25
Mechanical Considerations
The 3 Phase MegaPAC - EL and 4kW MegaPAC - EL 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 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 - EL and 4kW MegaPAC - EL 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 - EL and 4kW MegaPAC - EL. For the 4kW MegaPAC - EL, the
fans move approximately 50 CFM of air while for the 3 Phase MegaPAC -EL, the fan
moves approximately 30 CFM of air. The 4kW MegaPAC - EL has a second fan for
additional cooling.
Avoid excessive bending of output power cables after they are connected to the 3
Phase MegaPAC - EL or the 4kW MegaPAC - EL. 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 3 Phase MegaPAC - EL and
UG:108
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Applications Engineering: 800 927.9474
Page 2
4kW MegaPAC - EL 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 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
n
For units without Autosense,
do not leave ConverterPAC Sense lines open. Always
terminate them to their respective outputs locally or at the load. Use twisted
pair 22-24 AWG wire. If ConverterPAC has Autosense, no local sense connection
is required.
See page 12 and 16 for more information on Autosense.
n
If needed, use Connector Kit # 19-130041 for the 3 Phase/4kW
MegaPACs/EL - Low Noise.
n
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 airlfow escape from an empty
slot significantly degrades thermal performance, and can result in overheating and
damage to the power supply.
n
Do not unplug ConverterPACs while input power is applied. They are not
designed for hot-plug applications.
n
Do not restrict airflow to the unit. Leave 2 inch minimum space in front and
behind the supply.
The cooling fan draws air into the unit and forces it out at the
output power terminals.
n
For power expansion, use booster ConverterPACs. Viewing the unit from the output
terminal side, always insert boosters to the right side of the driver.
n
Do not use boosters as independent outputs. Disconnecting bus bars will damage
booster ConverterPACs.
n
Always ensure that output hex-nuts are properly torqued before applying
power to supply.
n
For booster arrays,
do not remove busbars.
n
Run the output (+/–) power cables next to each other to minimize inductance.
n
Wait 5 minutes after shutting off power before inserting or removing ConverterPACs.
n
The MegaPACs does not have user serviceable components. They must be returned to
the factory for repairs. Contact Customer Service for a RMA number before returning
the unitDo not attempt to repair or modify the power supply in any manner other
than the exchange of ConverterPACs as described in this Design Guide.
n
Insert proper fault protection at power supply input terminals (i.e., a fuse).
n
Use proper size wires to avoid overheating and excessive voltage drop.
n
Never loosen the inner nut on a ConverterPAC.
n
Verify output nuts are tight before powering up.
n
Keep in mind that the Regular Length ConverterPACs cannot be inserted in
the 3 Phase/4kW MegaPAC/ELs - Low Noise chassis because the Regular Length
ConverterPACs are too short to fit in the extended length chassis. The Extended
Length ConverterPACs are sometimes referred to as the
QuietPAC
(or
QPAC)
Family of Low Noise ConverterPACs.
n
Currently, the QPAC (XQ) is only used in the 4kW MegaPAC/EL (Low Noise).
UG:108
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Applications Engineering: 800 927.9474
Page 3
Technical Description
The 3 Phase MegaPAC - EL and 4kW MegaPAC - EL are configured by installing same
length ConverterPAC assemblies into the chassis. The chassis takes AC input power and
performs filtering and rectification functions. The ConverterPACs plug into a high-
voltage backplane and provide low-noise, independently regulated and fully
isolated outputs.
Input AC mains voltage (L1, L2, L3 and GND) is applied to an agency approved mating
plug. The input current is passed through an EMI filter designed to meet EN 55022 Level
A before it is passed to a three-phase full-wave bridge rectifier. The rectifier charges
storage capacitors and delivers unregulated 300 Vdc to a backplane after passing
through a large choke that improves input power factor. The power factor typically
exceeds 0.9 depending upon load, line voltage, frequency and line balance. Inrush
current is actively controlled with an IGBT and never exceeds 30 A peak regardless of
hot or cold starts or input volatage.
A housekeeping supply, isolated from the AC input, powers the brushless DC cooling
fan and other input monitoring circuits, in addition to providing an auxiliary +5 V
power source for the user.
The 4kW MegaPAC - EL has a second fan for extra cooling.
Excessive input currents caused by loss of a phase or excessive output loading in single
phase operation will safely shut down the unit until input power is recycled. This occurs
when the peak input current reaches 30 A. An analog temperature monitor is provided,
as well as overtemperature shutdown. An active-high TTL compatible Enable control is
included for each ConverterPAC assembly, as well as an active-low General Shutdown
control; the polarities, active-high or active-low, are factory set. Two (or more) 3 Phase
MegaPAC - ELs can be safely paralleled with accurate current sharing for high power
systems. Two (or more) 4kW MegaPAC - ELs can be safely paralleled with accurate
current sharing for high power systems All interface signals are safety isolated using a
common floating return.
Upon power-up, all outputs are first disabled to limit the inrush current, and to allow
the unregulated bus to reach correct operating levels for ConverterPAC assemblies. The
internal housekeeping supply comes up within 500 ms after input power is applied, and
the AC Power OK signal asserts to a TTL "1," indicating the input power is OK. The low
voltage power outputs come up within 10-20 ms after the AC Power OK asserts to a
TTL "1." Output ramp-up time from Enable or General Shutdown is 10-20 ms.
Output fall time from Disable is dependent on load, but is typically a few hundred
microseconds.
Figure 1.
3 Phase MegaPAC - EL and
4kW MegaPAC - EL Architecture
J1
Input
Power
IGBT PFC Choke
+P, -P
Output
Power
EN 55022
Level A
3 Phase
Full-Wave
Rectifier
Fuse
DC/DC
Converter
2nd Fan here
in the 4kW
MegaPAC-EL
Start-up Control
Circuits
J10
Customer
Interface
Isolated
Housekeeping
Power Supply
Remote Sense,
Trim Interface
Opto-isolated
Control/Status
DC Brushless
Cooling Fan
Power Good
Interface
QPAC ConverterPACs (Up to 10)
3 Phase/4kW MegaPAC/EL (Low Noise) Chassis
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Applications Engineering: 800 927.9474
Page 4
Configuring and Reconfiguring MegaPACs
Most ConverterPACs of the same length can be easily added, replaced, or moved
by sliding the assemblies in or out of a MegaPAC chassis. They are driver QPAC
ConverterPACs and can be inserted into any available slot. For outputs greater than
200 Watts, a driver QPAC and one or more booster QPACs will be used. For outputs
greater than 500 Watts, a driver QPAC (XQ) (in the 4kW MegaPAC - EL) and one or more
booster QPAC (XQs) 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 QPAC 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.
Torque the retaining screw to 0.23N-m
(2lb-in); do not overtighten.Power
and interface connections can be made after the
ConverterPAC has been installed.
Installing Booster ConverterPACs to Increase Output Power
Most ConverterPACs of the same length 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. For
the 3 Phase/4kW MegaPAC/ELs (Low Noise), all the driver and booster ConverterPACs
must consist of the Extended Length ConverterPACs. Bus bars between a driver and
booster (s) should never be disconnected. For help in identifying boosters and drivers,
refer to the section on Part Numbering on page 9. Please note that total output voltage
should not exceed the converter baseplate-output isolation rating of 400 V. For detailed
guideline on how outputs should be placed in series, please refer to the Applications
note available on the website at
www.vicorpower.com.
Figure 2.
Paralleling ConverterPACs
Bus Bars for Paralleling
Loosen screw to
remove ConverterPAC
1
Driver
Boosters: Slots 2, 3, 4
2
3
4
5
6
7
8
9
10
L1 L2 L3
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Applications Engineering: 800 927.9474
Page 5
PCB Design
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