DAB GRINDER GL, Instruction For Installation And Maintenance

Page: 31 / 292

GB
31
Use and maintenance instructions
English
Electric submersible pumps for sewage
Bimetallic thermal probes
Bimetallic thermal probles are incorporated in the motor winding have
the purpose to disconnect the pump in case of motor overheating.
The electric pump restarts automatically after a reasonable time
necessary for the cooling of probes.
Bimetallic thermal probles are a supplementary motor protection and
therefore it is always bìnecessary to foresee in the control panel a
differential thermal relay against overcharge or phase failure.
Sensor probes
Sensor probes are placed in the oil chamber assuring protection
against water ingress.
In case of intervention the instrumentation , generally located in the
control panel and connected to the probes, will send and acoustic or luminous alarm or, when requested,
will stop the electric pump.
Connection scheme fig. 14.
In case of alarm activated stop the electric pump, check the condition of oil and mechanical seal verifying
the reasons which have caused the intervention.
6. STARTING AND RUNNING
6.1 STARTING
Before starting the electric pump check again electric and hydraulic connections and relevant rating.
Check that all safety procedures and their good functioning have been activated.
Check that electric pump is correctly immerged and that the liquid level is allowing the correct starting.
Start the electric pump and check that value of current does not exceed
plate value and that the supply tension is on the foreseen limits.
Adjust, when present, the correct rating of the protection relay according to the working current value: the relay
must be rated 10% more than the electric pump plate value.
If the unit is not starting don’t insist. Identify the malfunction and repair the causes (see par. Defect of
functioning).
6.2 RUNNING
- Standard utilization conditions assure a long life to the electric pump.
- During running it is however necessary to periodically check the working conditions especially when solid or
thready substances are present in the pumped liquid.
- Be sure that number of startings per hour does not exceed the limits indicated and that same are equally
distributed in time.
- Frequent startings in a short time cause overheating and damages to electric winding.
- During inactivity of electric pump plan regular checks on motor insulation and, when present, on the electric
panel.
When electric pump is pumping solid or thready substances that could make deposits it’s necessary to provide
frequent washings with clean water. Check, furthermore, that suction grid, pit and eventual floating switch are
always cleaned.
7. MAINTENANCE
7.1 ROUTINE MAINTENANCE
Routine maintenance, limited to regular general checks, cleaning or replacement of few component parts must
be carried out by expert technicians only by suitable tools respecting the norm of safety of working ambient
and after becoming familiar with content of the present manual or any other documentation supplied with the
electric pump.
Fig. 14
Oil level probe connection
Oil control relay
Electric supply
50-60 Hz
24V AC
Oil
probe
Pump control switch