Background
Very often the usage of Water Pumps for Water storage
becomes a priority where pipe borne water is filled to
a storage sump tank and then pumped to a tank at a higher
elevation and used with gravity flow for useage.
There should be a large storage tank [ often called the
Sump tank built at ground level] which is the water source
one need to use to pump to a storage [utilizing tank]
tank. Often the storage tank has a lesser capacity than
the sump.
The main accessory we need for this project apart from
the Water pump and the DOL starter setup, are the float
switches.
Types of Float Switches
A float switch is a device which detects two water levels
and mechanically switching on and switching off an Micro
switch.[ there are also Mercury filled spring loaded sealed
tube types with On-Off action - which can also be used
] Some float switche have two floaters operated along
a cord.
Another Type which is very simple is a floating water
proof [plastic/pvc] device which contains a micro switch
inside and a moving weight which activates and deactivates
the micro switch and wired with a 3 core pvc water resistant
cable of about 2 mt. length.
The Micro switch is a 3 terminal type with a common terminal
and a NO and NC type switch.
[ There are electronic type water level detectors but
explained here is the mechanical type float switches]
The wiring of the DOL contactor needs to be changed slightly
for the Water pump operation.
The method explained in " Wiring DOL Contactor "
section is called 'Self Latching' type contactor wiring.
For the water pump operation, it is needed to operate
when the float switch is "ON" only and to stop
pump operation when the float switch is in "OFF"
position.
Understanding the Operating Principal
Sump Tank
One of the conditions for the water pump to work is
that there should be water in the sump to a pre defined
level.If the water level drops below a certain level,
the float switch makes the micro switch to "OFF"
position [contact broken]. When the water level reaches
a pre defined level above the minimum water level, the
float switch makes the micro switch to "ON"
position [contact made].
Storage Tank [ Usage tank]
The condition for the pump to activate is, when the water
level of the usage tank drops below the defined lower
water level.
The other condition for the pump to stop is, when the
water level reaches the maximum [upper] water level.
When the water level drops to a pre defined value, the
float switch activates the micro switch to the "ON"
position [contact made]
When the water level the upper pre defined level, the
float switch activates the micro switch to the "OFF"
position [contact broken]
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