Vicor Westcor PFC Mini Power Factor Corrected AC-DC Switcher - Manual (Page 3)

UG:115 vicorpower.com Applications Engineering: 800 927.9474 Page 3
When selecting a mounting location and orientation, the unit should be positioned so
airflow is not restricted. Maintain a 2" (5,1 cm) minimum clearance at both ends of the
PFC Mini, and route all cables so airflow is not obstructed. The power supply draws air
in at the fan side/AC input side and exhausts air out the load side. If airflow ducting is
used, avoid sharp turns that could create back pressure. The fans move approximately
20 CFM of air.
Avoid excessive bending of output power cables after they are connected to the output
terminals. For high-current outputs, use cable ties to support heavy cables and minimize
mechanical stress on connectors. Be careful not to short-out to neighboring outputs. The
maximum torque recommended on output nuts is 10 in. lbs.
Avoid applications in which the unit is exposed to excessive shock or vibration levels. In
such applications, a shock-absorbing mount design is required.
PFC Mini Do’s and Don’ts
n If Sense jumpers are removed, do not leave Sense lines open
(especially if unit does not have Autosense). Sense lines must be terminated to
their respective outputs. Use twisted pair 20-22 AWG wire when installing
Remote Sense.
n NEVER disconnect the +Out and -Out load wires while the supply is operating as
disconnecting WILL cause damage to the power supply. Ensure load wires connected
before remote sense connected.
n To prevent damage to supply, verify polarity of remote sense connection before
turning supply on.
n Always turn the power supply off before disconnecting input or output wires.
n Do not restrict airflow to the unit. The cooling fan draws air into the unit and forces it
out at the output terminals.
n Run the output (+/–) power cables next to each other to minimize inductance.
n Do not repair or modify the power supply in any manner. Doing so will void the
warranty. Contact Factory.
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 Output voltages over 60 Vdc, whether from individual modules or series arrays, are
considered as hazardous secondary outputs under UL60950. Appropriate care must
be taken in design implementation of the supply.
Technical Description
The PFC Mini consists of an offline single phase, power-factor-corrected front end, EMI
filter, cooling fan, customer interface, associated housekeeping circuits, and a selection
of Vicor’s DC-DC converters.
Input AC mains voltage is applied to a terminal block. The input current is passed
through an EMI filter designed to meet conducted noise limit “B” specifications in
FCC Part 15 and EN55022, Class B (with VI-200/VI-J00 series modules. If Maxi, Mini,
Micro series modules are used, it meets FCC Class A and EN55022 Class A. (Certain
configurations meet Class B).
At start-up, inrush current is limited by a PTC thermistor. The PTC is shunted out shortly
after initial power-up by a DC bus voltage sense circuit driving a relay. After rectification,
the input voltage is put through a boost converter that keeps the AC input current
sinusoidal and synchronized with the input AC voltage (in compliance with