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Siemens Simatic S7-400 User Manual

Page 490

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M7-400 Expansions

12-20

S7-400, M7-400 Programmable Controllers Module Specifications

A5E00069467-07

Example of Power Loss Calculation

The following table contains a calculation example for the total power losses for an
AT adapter module with an AT module.

Table 12-6 Calculation Example for Total Power Losses of an ATM 478 with AT Module

Remark

Voltage

Current

Consumption

Power Losses

+ 5 V

0.8 A

4 W

Power losses of the AT module

+ 12 V

0.1 A

1.2 W

Power losses of the AT module

- 12 V

0.05 A

0.6 W

- 5 V

Power losses of the internal power supply
of the

ATM 478 for supplying the AT module

(P

+12V

+ P

-12V

+ P

-5V

) x 0.3

(1.2 + 0.6 + 0) x 0.3 W

0.54 W

Power losses of the ATM 478 AT adapter module

0.6 W

Total power losses of the ATM 478 adapter module with AT module

6.94 W

In this example, the power losses are 6.94 W. The ATM 478 AT adapter module
can be operated without forced ventilation.

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