Electrical Connection; Frequency Converter Operation; Thermal Protection - Grundfos DWK Safety Instructions And Other Important Information

CAUTION
Crushing hazard
Minor or moderate personal injury
- Always check the lifting bracket and
chain for corrosion or wear before
lifting.
- Always lift the product by its lifting
bracket or by means of a fork-lift truck.
- Never lift the product by the power
cable or the hose or the pipe.
CAUTION
Crushing hazard
Minor or moderate personal injury
- Make sure the lifting bracket is
tightened before attempting to lift the
product. Tighten if necessary.

Electrical connection

DANGER
Electric shock
Death or serious personal injury
- A motor protector, set to rated current
+10%, must be installed by the
customer.
- Make sure that all protective equipment
has been connected correctly.
DANGER
Electric shock
Death or serious personal injury
- It is not permitted to extend the pump
cable. Contact Grundfos to get the right
cable length.
DANGER
Electric shock
Death or serious personal injury
- The motor-protective circuit breaker of
the pump controller must include a
circuit which automatically disconnects
the power supply in case the protective
circuit for the pump is opened.

Frequency converter operation

• The thermal protection of the motor must be
connected.

Thermal protection

One thermal switch is built into the motor winding
and will break the circuit in case of over temperature.
In case of intermittent operation, with water level up
to half of the motor, the thermal switch inside the
motor winding might be activated and cause the
pump to stop.
DWK
The following thermal protections can be found in
DWK pumps, depending on the specific pump type:
• thermal switch (Bi-metallic) type PTO or Klixon
• circuit breaker – Klixon (connected to the star
point of the stator)
• thermal sensor PT100 (PCA Platinium chip).
DPK 19 and 22 kW
• Thermal switch: As standard, a Klixon thermal
switch is installed, opening at a temperature of
130°C.
• Thermal sensor: A PT100 thermal sensors (PCA)
is installed.
The thermal switch must be connected according to
the wiring diagram fig. 3 or fig. 4. Make sure that the
alarm output will cause a motor stop in case of high
temperature in the motor.
The thermal switch must be connected to the control
wire of the power cable inside the pump and to the
safety circuit of the separate pump controller.
Checking after electrical connection
Use a multimeter to check the two signal wires of the
power cable. The circuit must be closed and the
resistance must be less than 1 Ohm.
Starting up the product
DANGER
Electric shock
Death or serious personal injury
- Before installation and the first startup
of the product, check the power cable
for visible defects and measure the
cable resistance to avoid short circuits.
DANGER
Electric shock
Death or serious personal injury
- Make sure that the power supply cannot
be accidentally switched on.
CAUTION
Sharp element
Minor or moderate personal injury
- Wear protective clothing (gloves) when
working on the pump or touching the
impeller.
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