janitza UMG 801, User Manual

Page: 77 / 106

www.janitza.de UMG 801
77
14.3 Measured current
The device:
·Measures current exclusively via current
transformers.
·Is designed for the connection of current
transformers with secondary currents of ../1 A
and ../5 A.
·Does not measure DC currents.
·Has current measurement inputs which can be
loaded with 120 A (sinusoidal) for 1 second.
The factory-set current transformer ratio is 5/5 A
and must be adapted to the current transformers
used as needed.
The current transformers require a basic insulation
according to IEC 61010-1:2010 for the nominal
voltage of the circuit.
1. Short-circuit all current transformer outputs
except one.
2. Compare the current displayed on the device
with the applied input current.
- The currents must match after taking the
current transformer ratio into account.
- In the short-circuited current measurement
inputs, the device must indicate approx. 0
amperes.
Fig. Phasor diagram
U
I
Voltage: Displayed with
long phasor
Current: Displayed with
short phasor
Sign of phase shift angle (U/I):
·Positive (+) with capacitive load.
·Negative (-) with inductive load.
INFORMATION
For explanations of the phasor diagram, see sec-
tion „14.6 Fundamentals on the phasor diagram“
on page 79.
L1 230.0V
2.229A
45.0°
40.0°
52.0°
2.228A
2.228A
229.7V
U1 U2 U3 I1 I2 I3
L2
L3
ESC
Phasor diagram 1-4
229.7V
14.4 Frequency measurement
For the measurement and calculation of measured
values, the device requires the nominal or mains
frequency. The mains frequency can either be
specified by the user or determined automatically
by the device.
·To determine the mains frequency, a voltage
greater than 10 V
eff
(4-conductor measurement)
or a voltage L1-L2 greater than 18 V
eff
(3-con-
ductor measurement) must be applied to voltage
measurement input V1.
·The mains frequency must be in the range from
40 Hz to 70 Hz.
·If the measured voltage is not sufficiently high,
the device cannot determine the mains frequency
and therefore cannot carry out a measurement.