XT40.721, XT40.722

– X-Series

Jan. 2007 / Rev. 1.0 DS-XT40.72x-EN All parameters are specified at 72V 13.3A, 3x400Vac (XT40.721) or 3x480Vac (XT40.722),

25°C ambient and after a 5 minutes run-in time unless otherwise noted.

www.pulspower.com Phone +49 89 9278 0

Germany

17/19

Loads such as decelerating motors and inductors can feed voltage back to the power supply. This feature is also called

return voltage immunity or resistance against Back- E.M.F. (Electro Magnetic Force).

This power supply is resistant and does not show adverse effects when a load feeds back voltage to the power supply.

It does not matter, whether the power supply is on or off.

If the power supply is fully loaded after a return-feeding event, the output voltage can dip to 21V for approx 20ms.

The maximum allowed feed back voltage is 87.9Vdc. The absorbing energy can be calculated according to the built-in

large sized output capacitor which is specified in chapter 7.

The XT40 Series of power supplies shall not be paralleled to increase the output power.

Power supplies can be paralleled for a 1+1 redundancy to gain a higher system availability and reliability. Redundant

systems require a certain amount of extra power to support the load in case one power supply unit fails. The simplest

way is to put two X-Series power supplies in parallel which is called a 1+1 redundancy. In case one power supply unit

fails, the other one is automatically able to support the load current without any interruption.

Please note: This simple way to build a redundant system does not cover failures such as an internal short circuit on

the secondary side of the power supply. In such a condition, the shorted unit becomes a load for the other power

supplies and the output voltage can not be maintained. This can be avoided by utilizing decoupling diodes.

Recommendations for building redundant power systems:

a)

Use separate input fuses for each power supply.

b)

Monitor the individual power supply units.

The power supplies of the X-Series can be put in series to increase the output voltage.

Fig. 25-1 Schematic for series operation

Installation notes for use in series:

Unit B

-

+

Load

+

-

AC

DC

AC

DC

-

+

Unit A

Earth

(see notes)

a)

It is possible to connect as many units in series as needed,

providing the sum of the output voltage does not exceed

150Vdc.

b)

Voltages with a potential above 60Vdc are no longer rated SELV

and can be hazardous in some situations. Such voltages must be

installed with a protection to make the unit touch-safe.

c)

For serial operation use power supplies of the same type.

d)

Earthing of the output is required when the sum of the output

voltage is above 60Vdc.

e)

Keep an installation clearance of 15mm (left/right) between two

power supplies and avoid installing the power supplies on top of

each other.

Note: Avoid return voltage (e.g. from a decelerating motor or

battery) which is applied to the output terminals.