Beckhoff EL3413-0000, Documentation

Page: 26 / 200

Product overview
EL34x3 26 Version: 4.4
Current types
The EL34x3 terminals can measure AC currents with a frequency of 45 Hz to 65 Hz and up to their 21
st
harmonic. Since such currents are frequently created by inverters and may contain frequencies of less than
50 Hz or even a DC component, electronic transformers should be used for such applications.
Overcurrent limiting factor FS
The overcurrent limiting factor FS of a current transformer indicates at what multiple of the primary rated
current the current transformer changes to saturation mode, in order to protect the connected measuring
instruments.
NOTE
Attention! Risk of damage to the device!
The EL34x3 terminals may not be continuously loaded with more than 5 A [EL3413-xxxx] or 10 A [EL3433-
xxxx] respectively! Additional intermediate transformers must be used in systems in which the overcurrent
limiting factors of the transformer allow higher secondary currents!
Protection against dangerous touch voltages
During appropriate operation of the EL34x3 with associated current transformers, no dangerous voltages
occur. The secondary voltage is in the range of a few Volts. However, the following faults may lead to
excessive voltages:
• Open current circuit of one or several transformers
• Neutral conductor cut on the voltage measurement side of the EL34x3
• General insulation fault
WARNING
WARNING Risk of electric shock!
The complete wiring of the EL34x3 must be protected against accidental contact and equipped with associ-
ated warnings! The insulation should be designed for the maximum conductor voltage of the system to be
measured!
The EL3413-xxxxx [
}
18] or EL3433-xxxx [
}
20] allows the maximum voltage for normal conditions as specified
in the technical data. The conductor voltage on the current side must not exceed this value! For higher
voltages, an intermediate transformer stage should be used!
An EL34x3 is equipped with a protective impedance of typically 1 MΩ on the voltage measurement side. If
the neutral conductor is not connected and only one connection is live on the voltage measurement side, the
resulting voltage against earth in a 3-phase system with a specific
line-to-line voltage [
}
18] is reduced by
the factor √3. This should also be measured on the side of the current measurement using a multimeter with
an internal resistance of 10 MΩ, which does not represent an insulation fault.
Additional measuring instruments in the current circuit
Please note that the addition of additional measuring instruments (e.g. ammeters) in the current circuit can
lead to a significant increase in the total apparent power.
2.5 Start
For commissioning:
• mount the EL34x3 as described in the chapter Mounting and wiring [
}
38]
• configure the EL34x3 in TwinCAT as described in the chapter Commissioning [
}
62] .