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Under the following 2 conditions, the rated transformer current is taken as the basic current for overload

detection:

•

The protection device is used as the protection of explosion-proof motors.

•

The protection device uses the standardized tripping classes according to IEC 60947-4-1 (VDE 0660,

Part 102).

In case of an auxiliary-voltage failure, the behavior of the thermal replica can be controlled via the Storage

of thermal replica parameter. For the protection device which is used as the protection of explosion-

proof motors, set the Storage of thermal replica parameter to yes. With this configuration, the

thermal state can be saved for 500 min. Once the supply voltage returns, the thermal replica continues to

function with the saved thermal state.

You can find more information in chapter 6.64 Thermal Overload Protection, 3-Phase – Advanced in the

SIPROTEC 5, 7UM85 Device Manual.

Voltage-Balance Supervision and Current-Balance Supervision

The Voltage-balance supervision function and the Current-balance supervision function detect the

following errors:

•

Unbalance of phase-to-phase voltages and unbalance of phase currents in the secondary circuit

•

Connection errors during commissioning or short circuits and interruptions in the secondary circuit

You can find more information in chapters 8.3.5 Voltage-Balance Supervision and 8.3.9 Current-Balance

Supervision in the SIPROTEC 5, 7UM85 Device Manual.

Analog-Digital Converter Supervision

The supervision principle of the Analog-digital converter supervision function is based on fast current-sum

supervision with the connection of the neutral-point current to the 4th current measurement input I

. If the

function supplies an implausible result for the sampled values, the protection functions of the device are

blocked.

You can find more information in chapter 8.4.2 Analog-Channel Supervision via Fast Current-Sum in the

SIPROTEC 5, 7UM85 Device Manual.

Application and Setting Notes

SIPROTEC 5, Additional Information on the Protection of Explosion-Proof Motors with Type of Protection Increased Safety e,

Manual

C53000-H5050-C078-1, Edition 03.2019

Siemens SIPROTEC 5 7UM85 User Manual

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