System Power Supplies

Acorn System Power Supply Photo

"These 30-Watt switch-mode power supplies have been specially developed for use in Acorn Eurocard rack systems. They are supplied as Eurocards, 100 x 160mm, fitted with DIN 41612 connectors. Use of 32, 64 or 96 way plugs loaded with the minimum number of pins enables both the inputs and outputs to be routed via the connector if required. Alternatively, the mains input can be hard wired through the front panel to termination pads on the PCB. The PCB layout and transformer construction are in accordance with I EC 380 and I EC 435 standards as regards safety isolation. Maximum component projection above and below the PCB is such that the cards may be installed in a 7E (1.4") dimensioned module although such installation requires some derating at higher temperatures.

Two versions are available:

Type AC7150 having a nominal 5V at 6A rating.

Type AC7151 having:     Output 1. 5V/3A

                                        Output 2. 12V/1.2A

The AC7150 has two independent secondary circuits each rated at 15 watts power capability. A preset potentiometer enables one of these secondary’s to be set up to any voltage between 4.5V and 7.5V. The other secondary tracks the first. Since both secondary’s are floating they may be connected in series, parallel or isolating modes.

Thus, the AC7150 is capable of producing a variety of outputs.

Examples are:

Parallel connection:        5V/6A

                                  or 7.5V/4A

Series connection:           9V/3A

     or 12V/2.5A

     or 15V/2A

     or 6-0, 6V at 2.5A each side.

In the AC7151 the 12V output is obtained by "stacking" a 7V secondary on top of the basic 5V secondary.

Both the AC7150 and AC7151 have the ability to operate from 115V or 230V nominal input line voltages, the appropriate range being selected by means of a link on the PCB.

These power supplies have the inherent ability to withstand output short circuits of less than 50 milliohm for an infinite time duration under worst case line input (265V).

The AC150/1 have been designed to have a MTBF of 30k hours under full load and nominal line input conditions with an ambient temperature of 25°C."

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