Parallel and Series Connec�on

PST14 Rev. 00

Page 6 of 20

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Redundant Systems Opera�on

Hold-up �me

The converter provides limited hold-up �me. If a hold-up �me is

required (some railways applica�ons for example), use external input

capacitors of adequat size.

Formula for addi�onal external input capacitor : C =2*Pout*th*100/

(V²-Vi²)/n

whereas :

C

= external input capacitance [mF]

n

= efficiency [%]

= hold-up �me [ms]

= minimum input voltage

V

= Input voltage level before interrup�on

Output Current Limita�on

See Electrical output data for value.

The converter output is con�nously protected against short-circuit by

a constant current limita�on. The short circuit protec�on is unlimited,

the opera�ng area between nominal power and ac�ve protec�on area

working in a constant current mode may lead to power above nominal,

then over stress of the internal components.

Thermal Considera�ons

The converter is designed to be mounted on a dissipa�ve area, in

conduc�on cooling mode. The max. opera�ng temperature is the

temperature of the baseplate which should not exceed 100°C.

Addi�on of grease or thermal pad between the converter baseplate

and the chassis is mandatory .

Thermal protec�on

A temperature protec�on is integrated in each Vicor module, disabling

output when heatsink temperature exceeds 105°C. The converter

automa�cally restarts, when the temperature drops below this limit.

Nevertheless, exceeding the max opera�ng temperature may cause

failures of the converter.

A converter output can be connected in series with an output from

a separate converter, an internal diode across each output is imple-

mented internally. The maximum output current of a serial-connected

outputs is limited by the output with the lowest current limit. Output

voltages above 48V (SELV - Safety Extra Low Voltage) require addi�onal

safety measures in order to comply with interna�onal safety require-

ments.

Parallel opera�on is possible with PST14 Mini & Maxi to increase output

power (see below parallelling signal).

When systems require a very high level of reliability and should work

normally in the event of a failure, N+1 redundancy is implemented

where N is the number of converter to support power requirement.

If one converter fail, the remaining ones s�ll delivers the power to the

loads.

Oring diodes are required to ensure proper N+1 opera�on (included

with op�onal N+1 bus bar).

Waveforms

Inrush : PST14B48-48250

Start-up �me : PST14B48-48250

100V 50ms Transient protec�on (M op�on) : PST14A24-28400-M

No inrush limi�ng circuit, peak value and waveform depend on input source

impedance. (see table page 2 for input capacitance)