FLOAT CUM BOOST CHARGER: -
in substation,
control unit, SCADA unit we use the battery bank for operation of relay and
circuit breaker.
At the condition of supply failure our SCADA
system will not get shut down due the battery bank.
when supply will restore, we required supply
to operate the panel to connect the load, which get form the battery bank
so for
maintain this battery bank continuously charge we required the battery charger.
we used
the float cum boost battery charger to charge the battery bank .
the diagram
for float cum boost battery charger is as shown in fig.
CONSTRUCTION:
-
It contains
the three-phase ac supply with to battery charger is attached.
This three-phase
ac supply is connected to the input of both float and boost battery charger.
Both the
battery charger contains the rectifier circuit at output. Between the both
charger there is VC contactor, which separate both from each other.
It also
contain the battery bank of 110 v .
WORKING: -
From fig, normally
we charge the battery bank form the float charger.
The float
charger input is connected to the 3-phase ac input supply. Then it converted
this ac supply to dc and connected to the battery and also load because it performs
two function:
1.sypply load.
2. charge
the battery.
When battery is completely dead at that condition battery is charged through boost charger which produce large voltage for small time of period to boost the charging.
when we used boost charger at that time float charger is off and also VC contractor is disconnected.
Boost charger
can also supply the load but through diode to limit the voltage. because boost
charger gives 2.6 voltage for each 2v battery, so for 110v it will be 143v and
this voltage is not good to directly connected to the 110v load.
HOW TO
CALCULATE FUSE RATING FOR MOTOR
Fuse rating
for 40 HP 3 phase motor: -
Fuse rating
for 30 kw 3 phase motor: -