Motor Wiring; Connecting The Motor Cable; Resistance Measurement - Lorentz PSk2-7 Manuel D'installation Et De Fonctionnement

52 Pump Installation

9.3.2 Motor wiring

9.3.2.1 Connecting the motor cable

The surface pump motor has a wiring box that contains the
connection terminals for the three motor phases.
The pump motor provides bolt terminals to connect the mo-
tor cable. For a professional and reliable conenction it is re-
quired to use cable lugs for connecting the motor cable to
the bolt terminals.
The motor phases are labeled with "U", "V", "W".
CAUTION – The wiring order will have
impact on the motor rotation direction.
The correct rototation direction is marked
with an arrow sticker on the pump and
motor.
CAUTION – Observe the rotation direction of the pump
when the system installation is finished and the pump was
been successfully primed with water.
In case the rotation direction is incorrect exchange any two
of the three motor phases to reverse the rotation direction.

9.3.2.2 Resistance measurement

We recommend checking the winding and insulation resist-
ance before connecting the pump to the controller. For a
surface pump these measurements should be done BEFORE
taking the pump into operation.
WARNING – Before starting any work on
the pump system, make sure that the
electricity supply has been switched off
and that it cannot be accidentally
switched on!
To measure the winding and insulation resistance discon-
nect all motor leads from the controller. A good quality mul-
timeter is necessary to measure the phase-to-phase resist-
ance with an accurancy to the first decimal place. ("0.1
Ohms"). It is also adviseable to consider the resistance of
the multimeter leads when measuring very low values:
Hold the tips of the multimeter together and note the value.
Always substract this value from your motor resistance
measurements!
Winding resistance
1. Set the multimeter to "resistance measurement" and
select the lowest measuring range.
2. All PSk2 motors are 3-phase motors. Measure the
resistance of phase-to-phase: L1-L2, L2-L3, L3-L1.
Make sure there is good contact between the probes
and the cable.
3. The deviation between the phases should be within
10 %. If the deviation is too high, the reason is likely a
damaged submersible cable or a faulty cable splice.
4. The absolute value is made up of the resistance of
the motor winding and the submersible cable. The
resistance of the submersible cable depends on its
length and size. For copper cable, the values of the
table below "Table 11: Motor cable resistance" below
and "Table 12: Motor cable resistances for surface
pump motors" on page 53, can be used as a rough
approximation.
Table 11: Motor cable resistance
Cable
4 mm / AWG 11
2
6 mm / AWG 9
2
10 mm / AWG 7
2
16 mm / AWG 5
2
Resistance
[Ω / 100 m]
0.40
0.25
0.17
0.10