6

Three-phase Input Switch Mode Power Supply

S8VT

Notice

Three phase input operation when one phase is missing

The S8VT will in most cases continue to operate even after the loss

of one phase of the supply. The performance specifications are of

course not guaranteed under these conditions. As the loss of one

phase puts additional stress on some components, the life span of

the unit could be shortened. It is prudent therefore to regularly check

for signs of the following possible conditions.

1. Input terminals wiring open/loose.

2. Incorrect/No voltage on one or more phases of the supply.

3. Abrupt or periodical loss of input voltage.

The power supply needs output derating as in the chart for the oper-

ation on missing phase at the input voltage range of 340 to 576 V.

Otherwise, the power supply may deteriorate or be damaged.

In every single application suitability has to be checked.

Note: In two phase operation, the specification for EMC perfor-

mance, hold-up time, efficiency and output ripple will no longer be

valid.

Three phase input switch off

In order to switch off the Power Supply completely: All 3 phases need

to be switched off.

Mounting

To improve and maintain the reliability of the Power Supply over a

long period, adequate consideration must be taken to heat radiation.

The S8VT is designed to radiate heat by natural air cooling, there-

fore, mount the S8VT so that enough air flow takes place around the

power supply.

If installing S8VTF closely, keep the minimum distance of 20 mm at

60°C ambient.

Generating (

±) Output Voltage

An output of

±can be generated as shown below, since the S8VT has

a floating output.

Serial Operation

As shown below, the output voltage from each S8VT can be added.

Types must be the same.

Parallel Operation

As shown below, two S8VT-F (same capacity model) can be paral-

leled to boost the output power (current). Set the output voltages of

the Power Supplies to the same value.

Also, make sure that the thickness and the length of all wires con-

nected to the load are the same to ensure that the wires will have no

voltage drop difference.

Parallel connection is only permissible with ambient temperature

from -10°C to +50°C.

In case of a redundant system or back-up system, use diode to be

connected to output + terminal of all the Power Supplies.

-20 -10

0

10 20 30

Ta (°C)

40 50 60 70 80

0

10

20

30

40

50

60

Load

(%)

70

80

90

100

110

Missing phase de-rating

S8VT-F48024E

S8VT-F96024E

S8VT-F12024E

S8VT-F24024E

+ V

− V

+ V

− V

+V

−V

+V

−V

+ V

− V

+ V

− V