Providing A Check Valve And A Level Sensor; Switching On The Motor; Operating A Motor With A Frequency Converter - Franklin Electric 226-Serie Montage- Und Betriebsanleitung

Caution
6.2

Providing a check valve and a level sensor

6.3

Switching on the motor

6.4

Operating a motor with a frequency converter

Damage to the motor and the motor cable due to overheating
 Make sure that the coolant flow speed along the motor is sufficient.
 Make sure that the short motor cable is always fully surrounded by transport medium for proper
cooling.
Figure 6-1: Cooling tube
If the required minimum coolant flow speed cannot be reached (e.g. if the inlet opening of the well is
located above the motor or if using large-diameter wells):
 Fit a cooling tube (see figure 6-1).
 Make sure that the cooling tube encases the entire motor and the pump water inlet opening.
The motor is force-cooled.
 Provide one spring-loaded check valve in the production tube in case no such check valve has been
fitted in the pump.
 Ensure that the first check valve is no further than 7 m (metres) away from the pump.
 Install a level sensor for wells with a highly varying water inflow.
 All action steps of the previous chapter have been carried out properly
 Switch on the motor using the mains switch in the control cabinet.
 Measure the following values after switching on:
Motor operating current in every phase
Mains voltage when motor is running
Level of the medium to be transported

Immediately switch off the motor if:
- the nominal current as specified on the type plate is exceeded,
- voltage tolerances of more than -10 % / +6 % to 50Hz and +/- 10% to 60Hz, relative to the nominal
voltage are measured on the motor,
- there is a risk of the motor running dry,
- a motor current deviates from the mean value of all three currents by more than 5 %.
Note
When operating a motor with a frequency converter, the relevant operating manual must be observed!
 Make sure that the motor current in all operating levels of the regulating range does not exceed the
nominal motor current indicated on the type plate.
 Adjust the frequency converter so that the limit values for the nominal motor frequency of min. 30 Hz
and max. the value of the nominal motor frequency (50 or 60 Hz) are observed.
 Limit any voltage peaks on the motor when using a frequency converter to the following values:
max. voltage rise 500 V/µs, max. voltage peak 1000V.
 Make sure that the running up time from 0 to 30 Hz and the deceleration time from 30 to 0 Hz is
maximum one second.
 Dimension the cable such that power loss due to additional filters is taken into consideration.
Encapsulated Submersible Motors
6 Motor operation
11