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3 Installation and Commissioning
3.3.5
Checking the Analog Outputs
3.3.6
Testing User-Defined Functions (CFC)
3.3.7
Checking the Rotor Earth Fault Protection at Stand-Still
3.3.7.1
Rotor Earth Fault Protection (R, fn)
352
7UM62 can be equipped with up to 2x2 analog outputs. Where analog outputs are
provided, and used, their functioning should be tested.
Since various types of measured values or events can be output, the test to be
performed depends on the type of values for which it will be used. These values must
be generated (e.g. with some secondary test equipment).
Make sure that the values are correctly output at their destination.
A 7UM62 has a vast capability for allowing functions to be defined by the user,
especially with the CFC logic. Any special function or logic added to the device must
be checked.
Naturally, general test procedures cannot be given. Rather, the configuration of these
user-defined functions and the necessary associated conditions must be known and
verified. Of particular importance are the possible interlocking conditions of the circuit
breakers and other primary switching devices. They must be considered and tested.
The rotor earth fault protection can be checked with the machine at stand-still. The
coupling unit, however, must be supplied with an external a.c. voltage 100 V to 125 V,
or 230 V (50 Hz or 60 Hz). Please refer also to connection diagram Figure 2-95 in
Section 2.30.1).
Switch rotor earth fault protection (address 6001 ROTOR E/F) to Block. Relay.
In the case of machines with rotating rectifier excitation (Figure 3-19 left), an earth fault
is installed between the two measurement slip rings with the measurement brushes in
place. In case of machines with excitation via slip rings (Figure 3-19 right) the earth
fault is installed between one slip ring and earth. The unit now measures as earth
impedance only the reactance of the coupling unit and the brush resistance (in series
with a protective resistor for the coupling capacitors and/or a damping resistor). These
values can be read out under the Operational Measured Values:
R total = x.xx kΩ
X total = x.xx kΩ
ϕZtotal = z.z °
Rinput corresponds to the series resistance (brushes plus protective resistor) and
Xinput corresponds to the capacitive reactance (a negative value indicates an
inductive reactance). If both values are indicated as 0, then the connections of Urotor
or Irotor have wrong polarity. Change the polarity of one of the connections and repeat
the measurement. It must then be checked that the setting values
R SERIES = xxx Ω (address 6007)
7UM62 Manual
C53000-G1176-C149-3
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