The indication resets after a preadjusted time (possible are three values: 1-2-4h). However, the indicator can be reset any time with a magnet, which must be placed at a marked spot. The instrument has a test function.
By request, the instrument can be equipped with a relay for remote indication.
The sensor consists of a black plastic housing which incorporates the elements for processing the earth fault current. The housing is fully sealed (IP67).
The sensor is mounted on the cable with an infinitely variable plastic belt. In order to pick up the current, a multilayer steel belt is laid around the cable. The steel belt is plastic-coated (indication accuracy +/- 10%). The sensor is connected to the reading instrument via cable (standard length: 3000mm).
special orders:
1) other operating points than standard values
2) other reset-times than standard values
3) length of minimum impulse duration
4) lenght of sensor cable #;#
|
Order-No. of Earth Fault Indicator Type EFL | ||
|
version |
without remote indication |
with remote indication |
|
L |
21.10.01 |
21.11.01 |
|
S |
21.10.02 |
21.11.02 |
Order Data
Earth Fault Indicator Type EFL
cable diameter: .............mm
order-number : ................. #;#
<EFL270303aee>
42553 Velbert/Germany * Fax +49-2053/422899
Elektro-Mechanik GmbH
E-mail: kus@emg-ger.com * internet: http://www.emg-ger.com
Technical Description
Setup
The earth fault indicator type EFL consists of:
1.) reading instrument
2.) sensor
3.) connection cable
The electronics of the indicator is incorporated in a cylindric housing. The electronics are fully sealed and thus protected against every kind of damage or environmental influences.
The instrument can be opened to change the battery, to select the operating points or to connect the cables of the sensor. The housing complies with the protection class IP655 and is suitable for indoor or outdoor installation. The housing can be used as a panel-mounted or as a surface-mounted instrument.
In order to assemble the instrument as a panel-mounted device, two drillings with a diameter of 4.5 mm have to be placed. The housing must be fixed with two screws M4x50. The surface-mounted instrument has to be fixed with two screws, too. Additionally, there has to be a viewing window with a diameter of 38 mm .
The sensor consists of a housing and a fully sealed coil. The sensor has to be fixed with a plastic-covered steel tape. #;#
Function
The sensor is mounted around all three cores of the cable, in order to detect the sum current of the conductors (cores) L1, L2, L3. Normally, the sum current is about 0A. If there is an earth fault in one of the cores, the balanced current will increase due to this asymetric situation. This inreased current will be detected and transmitted to the reading instrument for evaluation. The earth fault will be indicated, if the fault current exceeds the preadjusted operating point.
In order to avoid wrong indications caused by current peaks (e.g. due to switching processes), the indicator is equipped with a setting for minimum impulse duration. All impulses from the sensor are checked. For example, the indicator is adjusted to a minimum impuse duration of 40 ms. If the incoming impulse is shorter, no earth fault will be indicated. If the incoming impulse is longer than 40 ms and exceeds the operating point, an earth fault is indicated. This minimum impulse duration can be adjusted in the range of 30 to 200 ms.
Fault Detection
The earth fault is indicated by all indicators between the net input and the place of the fault. Therefore, the earth fault is between the last blinking indicator and the first indicator which is in stand-by mode. #;#
figure 1
38
figure 2
Technical Data
reading instrument: dimensions of the housing: diameter: 58 mm, length: 45 mm
selectable operating points: standard: 10 - 20 - 40 - 80 A (+/- 10%)
(other values are possible)
temperature range: -200 C to +60 0 C
minuímum impuls duration: standard: 40ms (selectable: 40 ms to 200 ms)
power supply: lithium battery 3.6 V
sensor: dimension of the housing: (W*H*D) 39*39*26mm
mounting: for round cores beween 40 mm and 130 mm
(diameter has to be placed in the order)
cable length: standard: 3500 mm (other length is possible)