Pump Installation 6766 Pump Installation
EN ENExample:
Motor:
AC DRIVE CS-F 7.5 kW 1.4 Ω
Motor cable:
150 m and 6 mm
2
0.25 Ω / 100 m
Calculation of expected phase-to-phase
resistance:
= 1.4 Ω + 2 × 150 m × 0.25 Ω / 100 m
= 1.4 Ω + 2 × 0.375 Ω
= 1.4 Ω + 0.75 Ω
= 2.15 Ω
= ~ 2.2 Ω
The real measured values can be dierent,
depending on the measurement equipment
and materials that are used. This is just an
approximation.
Table 14: Motor cable resistances for surface pump motors
Surface pump CS-F motors PSk3 system
Phase-to-phase resistance
[Ω]
AC DRIVE CS-F 5.5 kW PSk3-7 1.4
AC DRIVE CS-F 7.5 kW PSk3-9 1.4
AC DRIVE CS-F 11 kW PSk3-15 0.8
Surface Pump CS-G Motors PSk3 system
Phase-to-phase resistance
[Ω]
AC DRIVE CS-G 5.5 kW PSk3-7 1.7
AC DRIVE CS-G 7.5 kW PSk3-9 1.3
AC DRIVE CS-G 11 kW PSk3-15 0.8
AC DRIVE CS-G 11 kW/4p PSk3-15 0.8
Insulation resistance
Use a megohmmeter at 500 –1,000 V.
Measure each phase to ground. Connect one test
prod to the phase hold the other test prod to the
pipe work, or if plastic pipes are used to the ground
wire.
If the insulation resistance is below 0.5 MΩ, the
motor cable must be checked for damage.
Table 13: Motor cable resistance
Cable Resistance [Ω / 100 m]
4 mm2 / AWG 11 0.40
6 mm2 / AWG 9 0.25
10 mm2 / AWG 7 0.17
16 mm2 / AWG 5 0.10
25 mm2 / 4 AWG 0.066
35 mm2 / 2 AWG 0.047
50 mm2 / 1 AWG 0.033
70 mm2 / 2/0 AWG 0.023
95 mm2 / 3/0 AWG 0.018
To measure the winding and insulation resistance
disconnect all motor leads from the controller. A
good quality multimeter is necessary to measure the
phase-to-phase resistance with an accuracy to the
rst decimal place. (“0.1 Ohms”). It is also advisable
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 PSk3 motors are 3-phase motors. Measure
the resistance of phase-to-phase: 1-2, 2-3, 3-1.
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 "Table 13: Motor
cable resistance" and "Table 14: Motor cable
resistances for surface pump motors" on page
67, can be used as a rough approximation.
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