Wilo EMU TR 212 Instrucciones De Instalación Y Funcionamiento página 26

en-US
6.5.2 Maintenance work
6.5.2.1 Checking insulation resistance of
the motor winding
6.5.2.2 Checking resistor in the tempera-
ture sensor
6.5.2.3 Check the resistance of the exter-
nal electrode for pre-chamber
monitoring
6.5.3 Connection of the three-phase
current motor
26
Installation and electrical connection
Motor protection switch
For products supplied without a plug, a motor protection switch must be installed on-site.
The minimum requirement is a thermal relay/motor protection switch with temperature
compensation, differential triggering and an anti-reactivation device, in accordance with lo-
cal regulations. Further protection devices (e.g. overvoltage, undervoltage, or phase-failure
relay etc.) must be provided on-site for sensitive power supplies.
Residual-current device (RCD)
ƒ
Install residual-current device (RCD) according to the regulations of the local energy sup-
ply company.
ƒ
If contact with the product and conductive liquids is possible, install residual-current de-
vice (RCD).
Carry out the following maintenance tasks prior to installation:
ƒ
Check the insulation resistance of the motor winding.
ƒ
Test the resistance of the temperature sensor.
There are several reasons why the measured values differ from the specifications:
ƒ
Humidity in the motor.
ƒ
Humidity in the connection cable.
ƒ
Monitoring device faulty.
Contact customer service in the event of a fault.
Measure insulation resistance with an insulation tester (measuring voltage = 1000 V). Ad-
here to the following values:
ƒ
On initial commissioning: insulation resistance may not be less than 20 MΩ.
ƒ
For further measurements: value must be larger than 2 MΩ.
Check resistor in the temperature sensor with an ohmmeter. The following measured values
must be complied with:
ƒ
Bimetallic strip: Measured value = 0 Ohm (passage).
ƒ
PTC sensor (positive temperature coefficient thermistor): Measured value depends on
the number of sensors installed. A PTC sensor has a cold resistance of between 20 and
100 Ohm.
–
With three sensors in series, the measured value is between 60 and 300 Ohm.
–
With four sensors in series, the measured value is between 80 and 400 Ohm.
Measure the resistor of the electrode with an ohmmeter. The measured value must ap-
proach "infinity". For values ≤ 30 kOhm, there is water in the oil – change the oil!
The three-phase current version is supplied with bare cable ends. Connection to the mains
is established by connecting the connection cables in the switchgear. Refer to the attached
connection diagram for more precise details regarding the connection. Electrical connec-
tion must always be carried out by a qualified electrician!
NOTICE! The individual wires are designated according to the connection diagram. Do
not cut the wires! There is no additional assignment between the wiring diagram and
connection diagram.
Wiring diagram of the power connections for direct starting
U, V, W Mains connection
Polyethylene Earth
(gn-ye)
Wiring diagram of the power connections for star-delta starting
U1, V1, W2 Mains connection (start of winding)
U2, V2, W2 Mains connection (end of winding)
Polyethylene Earth
(gn-ye)
WILO SE 2021-05