Short Circuit Indicator type KRA

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Design
The short circuit direction indicator operates on an electronical basis. The electronics are incorporated in a
plastic housing. The instrument is fixed on the high voltage conductor with a steel tape.
The steel tape is infinitely variable to a certain extent.
The high voltage conductor energizes an accumulator, which in turn provides the power for the short circuit
direction indicator.
 
Function
In order to detect the energy flow, the phase postion of the voltage is compared to the phase position of the current in a conductor. For this purpose, the phase position of the voltage is absorbed by a capacitive detector and transmitted to the electronics. The phase position of the voltage is accumulated and can be used even when the voltage of the high voltage conductor is not applicable.
The phase position of the current in case of a short circuit is absorbed by a coil. The operating point is adjustable through a potentiometer.
The accumulated phase position of the voltage and the phase position of the current in case of a short circuit are transformed in a processor.
According to the ratio of the phase positon of the current to the accumulated phase position of the voltage, an LED indicates in which direction the energy has flown. The power supply for the short circuit direction indicator is carried out directly by the network. Therefore any kind of maintenance such as battery control or battery replacement becomes unnecessary.
After a short circuit indication the indication is reset automatically.
The reset times are choosable. Three reset times can be preadjusted.
 

Assembling

The place of assembly must be “switched off”
according to instructions!

Please choose the requested reset time before the assembly. The short circuit direction indicator must be installed on unscreened cables only.
The indicator must be fixed directly on the cable. For this purpose, the screws (2) are loosened so much that the frame tape (1)  can be withdrawn from
the terminal board (3) .
The frame tape must be wrapped around the cable,
fixed under the terminal board (3) and then pulled so much, that the rubber rings (5) are exposed to pressure.
The terminal board (3) has to be screwed with the screws (2). The projecting steel tape is bend sharply backwards
and then bend backwards around the cable.
Please make sure that the short circuit direction indicator will be mounted according to the suitable cable dimension (refer to label on the KRA).

 

Technical Data
Dimensions of the housing: (W*H*D*) = 44*53*28 mm
Operating current: 150A to 1000A (adjustable)
Precision: +/- 10%
Reset time: 3 times between 0,5h and 20h
                    (must be indicated with the order)
Temperature range: -20 to +70°C
Power supply: no auxiliary power supply
Power request: 20μA
 

 Short Circuit Indicator type KRA


EMG Elektro-Mechanik GmbH - Ringstr. 4 - D-42553 Velbert / Germany
Tel: +49-2053-422890 - Fax: +49-2053-422899 - Email: kus@emg-ger.com