Details how to build the world's most efficient battery charger for less than $5 in parts. Parts are readily available and the Capacitive Transformer concept is both easy to understand and b…Full description
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Automatic Battery Charger
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Application details and specific item requirements for batteries and chargers are laid out in this fifth installment of ARAMCO Desktop standards series. Enjoy!Descripción completa
Battery and Charger Sizing Calculation IEEE 485Full description
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110 SP 20 HBL Battery ChargerFull description
CBSE Physics Project on Dry Battery Charger. Includes circuit diagram. Ususally class 12th (XII) physics project topic. Just a few changes and the project will be ready or maybe use it as a …Full description
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battery chargerFull description
220 V DC SYSTEM index Description Battery Charger System Description : (a) Float Charger – SCR Control (b) Boost Charger - SCR Control Battery Charger Annunciation Details
DESCR!"#$
220 V. V. DC power supply is provided in each unit to provide stable DC supply to following: 1. Gener Generat ator or auxi auxili liar arie iess
DC seal oil pup! "xcitation Cubicle! Generator bac# up panel
2. Generator $elay %anel &. 'urbine auxiliaries
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1&2V $elay panel! 1&2V control des#! 1&2V close trip operation! .V station unit bus C.+. close trip operations relay auxiliary supply indications annunciations.
. "ergency lighting 3ll above loads are supplied fro D.C. distribution board charged fro +attery +an# consisting of lead cells! constantly under charging by battery charger! charger! 3c power to which are supplied either fro station auxiliary 4' 4' board 50.* #V6 and unit wise eergency )CC. D.C. System consists of following:
a. 7ne storage battery having 1/00 38 capacity at 10 hour discharge rate consisting of 110 4ead 3cid cells for each unit. b. 7ne float charger per unit. c. 7ne float cu boost charger per unit. d. 7ne D.C.D.+. per unit. 'he float charger will norally supply the load current float charging current of battery. 9nder this condition if 3C feeder to charger fails! battery will supply the load current. hen ains restore! if battery ta#es ore current than the float charging current! float cu boost charger will be switched 7; auto at float voltage.
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2. Capacity : 5a6 220v dc! 2/03 dc continuous 5b6 2*v dc! &03 dc continuous &. o of sets: 5a6 220v charger & nos. 5b6 2*v charger nos. *. !pplication: 5a6 Charging of 220v station batteries and supplying station 220v dc load 5b6 Charging of 2*v station batteries and supplying station 2*v DC load to electronic cards of DC- and +)- and relays via 2*v boards.
The float charger is meant for supplying the DC load and at the same time float charging the battery to keep it in fully charged condition. The float charger may either be operated in auto or manual mode. In the automatic mode the output voltage is held constant at a preset value whereas in manual position the output may be varied within specified limits by an external potentiometer. The incoming supply of the float charger will be fed into a phase double wound step down transformer thru! suitably rated switch fuse unit. The secondary of the transformer will then be fed to a phase full wave full control thyristorised bridges thru! surge suppressor and high speed semiconductor protection fuses. The bridge circuit consists of " nos. thyristors# which are ade$uately protected by snubber circuit against voltage transients and dv%df effect. The triggering of the thyristors are controlled by &.'.(. unit which senses feed back from the output voltage and current. These feedback signals are suitably processed and compared with the reference generated in the &.'.(. circuits. Then the error is amplified and phase compensated by high gain operational
amplifier. The incorporation of feedback ensures automatic correction of any deviation oh the set voltage# which may arise due to line or load fluctuations. The output of the final amplifier will be fed to triggering circuits# which control the output voltage of the float charger by ad)usting the firing angle of the thyristors. *ith the help of the &.'.( unit the regulation of the output voltage of the float charger may be kept around + or - , against line or load fluctuations. Due to incorporation of inner current loop by which the output voltage drops as the rated load is increased there by automatically transferring the load to the battery in order to avoid the overloading of the charger. In this system as described a suitable DC filter is provided to bring down the ripple to the re$uired level at the output. &mmeter and voltmeter are provided for monitoring output current and voltage respectively. ecessary indications are provided for different status and fault monitoring. B##S" CARER -- SCR C#$"R#' :-
Then booster charger is basically meant for $uick charging the battery after heavy discharge# so as to restore the capacity of the battery within minimum time. In this processed system the boost charger will be normally in standby auto float charge mode and will cut into the circuit automatically / a0 to provide occasional boost charge as re$uired /b0 to take over of the function of the float charger in case of the main float charger failure. The boost charger has also provision for float and manual boost charging the battery thru! manual selection. In this system the boost charger is an automatic constant current charger consisting of a suitably rated phase double wound step down transformer fed thru! a suitably rated switch- use unit. The secondary of the transformer is fed to -phase full wave full control thyristorised bridge thru! line surges suppressors and high speed semiconductor protection fusses. The bridge circuit consists of " nos. thyristors# which are ade$uately protected by snubber against voltage transients. Triggering of the thyristors is controlled by an &C( unit# which senses feedback from output current. These feedback signals are suitably processed and compared with the reference generated in the &C( circuit# then the error will be amplified phase compensated by high gain operational amplifier. The incorporation of the feedback ensures automatic correction of any deviation of the set current# which may arise due to line or load fluctuations.
*hen the battery draws ,1 times of maximum recommended trickle charging current# the battery charging starts at a starting rate which is automatically monitored by electronic circuit. 2nce the battery voltage reaches upto 3.4 v%cell# the charging current will automatically reduced to the finishing rate by a current control circuit which ad)usts the current limit reference to the charger with increased in the battery voltage. once the battery voltage reaches 3.54 v%cell the battery will automatically be transferred to float charger and float charging continues as usual manner. In this system the battery will normally float across the floatcharger so that in case of power failure the battery can maintain the load without interruption.6owever after heavy discharge of battery# the battery is placed on boost charger. ow if supply fails# the battery will be connected to the bus by a %2 contact of the DC contactor which remains de-energised when supply is present and battery is in boost charging condition# thereby disconnecting the battery and the boost charger from the load bus so as to maintain the load voltage within + or 7 , of the rated value# since boost charger output varies within wide limits depending on the battery voltage. 6owever if power supply fails# while boost charging operation in progress the battery should be connected to the load immediately to avoid any interruption. & diode is incorporated between an intermediate cell and the load bus. During normal operation the tap cell diode will be reversed biased. In the event of power failure during boost charging with battery isolated# the output voltage start dropping. &s soon as it drops slightly lower than the intermediate cell voltage# the diode will conduct thereby maintaining voltage at the load bus# though lower in magnitude# to avoid complete interruption of supply. 6owever after this brief interval the DC conductor will energises thereby connecting the battery to the bus restricting the original load voltage. Thus this arrangement provide an uninterrupted DC supply to the load. The following modes of operation of the boost charger can be selected with the help of mode selector switch:!#S"#$ * +
The boost charger will remain in de-energised condition with battery bank in healthy condition across the float charger. 6owever during continuous floating operation# the cells in the battery bank tends to fall out in steps# and float charging current increases and when it exceeds preset limit# the auto e$ualising relay /(8 790 energises. Then the
boost charger switches on in auto e$ualising mode and charging continues. *hen the battery voltage on charger increases to around 3.4 v%cell# the auto e$ualising relay /(8 7 90 de-energises thereby tripping energising the boost charger. Thereafter the battery again transfers to the float charger and float charging continues as usual manner. !#S"#$ * ,
In position , of mode selector switch# the boost charger can be operated as float charger provides the float se$uence /C,0 is off. !#S"#$*
In position the boost charging can be done manually thru! external current setting potentiometer /;30 provided on the front door of the boost charge panel. This mode of control is normally necessary during initial charging of the battery under manual supervision. !#S"#$ * .
In position . the boost charging is done in automatic two step charging mode i.e. at the starting and finishing rate of charge in constant current mode. BA""ER% CARER A$$/CA"#$ DE"A'S
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?loat%boost Charger Aecomes inoperative./&ssuming that Inc supply has failed.0
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ota &C input voltage
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o automatic action# if input &c voltage has not failed but there Change source , is a voltage to source 3 or surge. vice-versa and see if ann. Disappears. Check upstream feeders at Bcab.
