5.4
Measuring the insulation resistance
For your information
5.5
Powering the motor
DANGER
Energy supply by
generator
The unit manufacturer's instructions regarding the cable connection have been observed
Only extension cable and insulating material used which are suitable for the specific use (specifically
drinking water) and which are approved for the temperatures occurring in the relevant medium
Cable cross-sections: The tables in the appendix only serve as recommended suggestions. The fitter is
responsible for the correct selection and dimensioning of the cable
Lay the cable along the pump.
Connect the ground conductor correctly (motors or integrated ground conductors are prepared for
external grounding).
Protect the cable connection location against water penetration (shrink hoses, compounds or ready
cable sets).
Make sure that the short motor cable is always fully surrounded by transport medium for proper
cooling during operation.
This measurement is to be carried out using an insulation measuring unit (500 VDC, 1 min) before and
while submersing the fully assembled unit at the place of use.
Before submersing the unit, connect a measuring cable to the ground conductor.
Make sure that the contact points are clean.
Connect the other measuring cable to every core of the connected motor cable in succession.
The insulation resistance is shown on the insulation measuring unit.
Minimum insulation resistance (ambient temperature 20°C) with extension cable:
for a new motor > 4 M
for a used motor > 1 M
Minimum insulation resistance (ambient temperature 20°C) without extension cable:
for a new motor > 400 M
for a used motor > 20 M
Danger to life due to electrocution!
Prior to making the electrical motor connection make sure that there is no more voltage on the entire
plant and that nobody can accidentally switch on the voltage again while the work is being carried
out.
Observe the instructions on the motor type plate and dimension the electrical system accordingly. The
connection examples in this chapter concern the actual motor and do not serve as recommendation for the
upstream control elements.
All action steps of the previous chapter have been carried out properly
Note
We urgently recommend that you discuss the plant dimensions with the generator manufacturer.
The voltage tolerance, 50Hz: -10 % to +6 %/ 60Hz: ± 10%,(on the motor terminals) and the deviation of a
motor current from the mean value of all three currents must not be more than 5 %.
Generator selected on the basis of the motor start behaviour, i.e. starting current with a mean cos
0.5
Sufficient continuous generator power available
Rewindable Submersible Motors
5 Pre-Operation Checks
of
9