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b) Thermal protector
The motor (standard 11kW or larger and special model of 2.2kW~7.5kW) has a built-in thermal
protector that outputs signals via a cable. Connect the thermal protector cable
’s wires to the
control panel in accordance with the specifications in the table on the right, so that the pump will
be stopped if the motor
’s internal temperature rises too high.
Use this protector in combination with a 3E relay or similar for phase failure.
6
Operation
Warning
During the operation of the pump, do not insert hand or foot in the suction opening of
the pump to avoid injury at the rotary section.
Never operate the pump in water in the presence of personnel.
If electric leak occurs, the personnel may suffer electric shock.
Do not execute dry operation in air. That type of operation causes deterioration in
insulation to lead to electric shock and electric leak.
1. Before starting
1) After completing the installation work, measure again the insulation resistance in accordance with
５
-1 "Confirmation before installation".
2) Confirm that the water level is satisfactory. If the pump is operated for a long period of time under dry
condition or at near the operable minimum water level, the Auto-cut in the motor is actuated. If the
situation is repeated, the pump life becomes short. Once the Auto-cut is actuated, the motor does not
start until it is cooled. (Even during the period of Auto-cut functioning, the power is supplied up to the
pump. Since the pump will restart without indication, the inspection shall be given after cut OFF the
power source.)
3) Operate the pump within the range given in the chart.
4) Frequent start-stop operations damage the pump in early stage of life. Limit the starting frequencies
as below.
Motor out put
Less than 7.5kW
11~22kW
Frequencies of starting
Ten times per hour
Six times per hour
2. Test operation
…
Non-automatic type pump (Model DL)
…
Automatic type pump (Model DLA)
1) Turn the switches 1 - 2 on and off a couple of times
with the gate valve slightly opened to check that it
starts up normally. It should be noted that a DLA
model pump does not start unless the upper float is
positioned up.
2) Next, check the direction of rotation. Reverse direction of rotation is indicated by low capacity and
abnormal noise and vibration. If the pump is found to be running in reverse rotation, change
around the onnections of 2 of the 3 phases to obtain the regular rotation direction (See Fig. 8).
Fig. 5
Switch box
Motor
Motor
U1 V1 W1
W1
V1 U1
Switch box
Fig. 8