Electrical Connection; Line-Side Fuse Protection - Wilo Rexa PRO Serie Instrucciones De Instalación Y Funcionamiento

INSTALLATION

5.5. Electrical connection

ELECTROCUTION hazard!
Incorrect electrical connections can cause fatal
electric shocks. Electrical connections may only
be carried out by a qualified electrician ap-
proved by the local energy supply company, in
accordance with locally applicable regulations.
DANGER: from incorrect connection!
With Ex-rated pumps, the power supply cable
must be connected outside the potentially
explosive area, or inside a housing with an ap-
proved level of ignition protection. Non-obser-
vance may lead to fatal injury due to explosion!
• Always have the connection carried out by a
qualified electrician.
• Note the additional information about this in the
appendix.
• The line power current and voltage must be as stat-
ed on the rating plate.
• Connect the power supply cable in accordance
with the applicable standards and regulations and
according to the wire assignment.
• Any monitoring equipment to be used, e.g. for
thermal motor monitoring, must be connected and
tested to ensure that it is working properly.
• For three-phase AC motors, a clockwise phase
sequence must be present.
• Ground the pump properly.
Pumps that are permanently installed must be
grounded in compliance with nationally applica-
ble standards. If a separate grounding conductor
is available, it must be connected to the marked
hole or ground terminal (;) using a suitable screw,
nut, tooth lock washer, and flat washer. The cross
section of the cable for the grounding conductor
connection must comply with the local regulations.
• A motor protection switch must be used for mo-
tors with a free cable end. We recommend using a
residual current device (RCD).
• Switchgear must be purchased as accessories.

5.5.1. Line-side fuse protection

The backup fuse required must be rated according
to the starting current. Refer to the rating plate for
the starting current.
Only slow-blow fuses or K-type circuit breakers can
be used as the backup fuse.
5.5.2. Checking the insulation resistance and monitoring
devices before commissioning
If the values measured deviate from the specifica-
tions, moisture may have penetrated into the motor
or the power supply cable or the monitoring unit
may be defective. Do not connect the pump, and
consult Wilo customer service.
Installation and operating instructions Wilo-Rexa PRO
Insulation resistance of the motor winding
Before connecting the power supply cable, the
insulation resistance must be tested. This can be
measured with an insulation tester (measuring
voltage = 1000 V):
• On initial commissioning: insulation resistance
may not be less than 20 MΩ.
• For further measurements: value must be larger
than 2 MΩ.
For motors with an integrated capacitor, the
windings must be short circuited before checking.
Temperature sensor and pencil electrode (avail-
able as an option) for sealing chamber control
Before connecting the monitoring devices, these
must be checked with an ohmmeter. The following
values must be complied with:
• Bimetallic strip: Value = "0" passage
• PTC thermistor sensor: A PTC thermistor sensor
has a cold resistance of between 20 and 100 Ω.
If there are 3 sensors in series, this results in a
value of 60 to 300 Ω.
If there are 4 sensors in series, this results in a
value of 80 to 400 Ω.
• Pencil electrode: This value must approach infini-
ty. If the value is low, there is water in the oil. Also
observe the instructions of the optional evalua-
tion relay.
5.5.3. Single phase AC motor
Fig. 5.: Connection diagram
L
Line power
N
20
Bimetallic strip
21
The single phase version has a capacitor switchgear
(operating capacitor) and free cable ends.
The connection to line power is made in the switch-
gear.
Electrical connections may only be made by a
qualified electrician!
US English
Leakage detection for
DK
motor compartment
Cr Operating capacitor
PE Ground
19