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INSTRUCTION MANUAL
SERVO-CONTROLLED VOLTAGE REGULATOR
SE-15
Servel Electronics Pvt.Ltd.
4844 A, Govind Lane , Ansari Road
24, Daryaganj, New Delhi – 110002
Phone : 91-11-3261965, 91-11-3282422
Fax : 91-11-3284192
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CONTENTS
Page No
1.Introduction
3
2.Specification & Features
4
3.Principles of operation
10
4.Installation & operating Instructions
13
5.Maintenance
16
6.Major components
20
7.Fault finding flow chart
19
DRAWINGS
Fig.1 Cct diagram for Single phase SCVR
11
Fig 2 Cct diagram for Three phase SCVR
12
Fig 3 Control panel for Single phase
6
Fig 4 Control panel Three phase
7
Fig 5 Fault Diagnostics tree
17
Fig 6 Sub-assembly Motor Mounting plate
21
Fig 7 Component layout-control card
22
Fig 8 Schematic-control card
23
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INTRODUCTION
Excessive voltage variations are highly dangerous for the sophisticated Electrical
and Electronic Equipment such as electromedical equipment, computers,
communication equipment & systems, process controllers etc
The equipment require a specified constant stabilized Voltage Source for their
desired optimum operation. The small variations in the input voltage affect the
performance of these equipments to a considerable extent, whereas the large
variation in the input voltage are highly dangerous.
Serve Controlled Automatic Regulator (SCVR) provides complete protection to these
sophisticated equipments against the large input voltage variations
SCVR monitors, corrects and maintains the desired specified output voltage by
adding or subtracting the required amount of voltage to/form the input voltage
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SPECIFICATIONS & FEATURES
SCVS 1 KVA Single Phase
2.1 Input Voltage
2.2 Output
2.3 Capacity
2.4 Voltage Correction Rate
2.5 Wave Form Distortion
2.6 Temperature Range
2.7 Other Features
2.8 Protections
160 – 260V, 50 Hz
230V + 1% (adjustable with + 10 V)
1 KVA, 1 phase
20 volts/sec
None added
0-55 C
a) The unit is designed instant
serviceability by providing PLUG in
control CKT card and PLUG in
connector for panel
b) The unit can made to operate
manually through the AUTO/MANUAL
selector switch Push switches
INCREASE and DECREASE can
increase/decrease o/p voltage when
AUTO/MANUAL selector switch is in
MANUAL position
a) Output is automatically switched
OFF if it is below 205 Volts or above
245 Volts and automatically switches
ON when safe voltage returns
b) Overlead protection provided
through Miniature Circuit Breaker
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SPECIFICATIONS & FEATURES
SCVS 1 KVA Single Phase
2.1 Input Voltage
2.2 Output
2.3 Capacity
2.4 Voltage Correction Rate
2.5 Wave Form Distortion
2.6 Temperature Range
2.7 Other Features
2.8 Protections
160 – 260V, 50 Hz
230V + 1% (adjustable with + 10 V)
1 KVA, 1 phase
20 volts/sec
None added
0-55 C
a) The unit is designed instant
serviceability by providing PLUG in
control CKT card and PLUG in
connector for panel
b) The unit can made to operate
manually through the AUTO/MANUAL
selector switch Push switches
INCREASE and DECREASE can
increase/decrease o/p voltage when
AUTO/MANUAL selector switch is in
MANUAL position
a) Output is automatically switched
OFF if it is below 205 Volts or above
245 Volts and automatically switches
ON when safe voltage returns
b) Built in Time-Delay for 5-6 minutes
for re-start
c) Overload protection provided
through Miniature Circuit Breaker
d) Protection with auto switch off/ fault
signal against single-phasing excessive
input, Unbalance/phase-reversal
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Uv / ov cut off relays relays
On when o/p voltage is with
in limits
Control circuit for
‘R’ phase similar
Control circuit for
‘Y’ and ‘B’ phase
R1,Y1,B1,N1-Ac input supply 30/
T1R,T1Y,T1B- Variacs 3 nos
T2R,T2Y,T2B- Series transformer 3 nos
M.C.C.B – Moulded case circuit breaker
NE – o/p on indicator
Lm1-11-lamp for low limit
Lm2-h1-lamp for high limit
S2 push switch for increase manual
S3 push switch for decrease manual
R0,Y0.B0,N0. – 3phase ac out put supply
M – Motor
C – Capacitor
MS1-L1-Micro switch for low limit
Ms2-L2 – Micro switch for high limit
R – Resistance
S4 Tossle switch for auto manual
TR3 Sensing transformer
CIRCUIT DIAGRAM FOR
S.C.V.R. 30 – UNBALANCE TYPE (I.C)
DRN
CHD
Appd
Date
SERVO ELECTRONICS
OKHLA PHASE-2, NEW DELHI-20
1.9.90
DRG NO 90022
-9-
- 10 -
3. PRINCIPLE OF OPERATION
The Servel SCVR are available in three different models to cater for
Single Phase and balanced/unbalanced Three Phase supplies
3.1 (TYPE-SE- 15 – 10 SINGLE PHASE MODEL
Suitable for Single Phase input supply and load
It consists of following sub-assemblies: a) Variable Transformers driven by the synchronous servo motor
b) Series Transformer
c) Electronic Control
The Syn. Servo Motor driven variable Transformer feeds the primary winding of
the double wound series Transformer secondary winding to add or subtract the
correcting voltage to the input Line voltage (Ref Fig.1)
The Electronic Control circuit monitors the O/P Voltage. In case of voltage
variations the control circuit drives the Servo Motor to correct the O/P voltage
within the rated limits
3.2 (TYPE-SE – 15 –3U) THREE PHASE MODEL
Suitable for Unbalanced 3-phase input supply voltage and/or Unbalanced Load
It consists of three single phase units with completely independent control for
each phase. These units are suitable for any amount of unbalanced supply and
load (Ref. Fig.2)
3.3 OTHER FEATURES
3.3.1 SINGLE PHASE MODEL
1) Under/Over Voltage Protection is provided using relay/contactor being driven
by electronic control circuit
2) Filter is provided to suppress the undesired transient interferences and noise
3.3.2 Three Phase Model (Unbalanced Type)
1) Under/Over Voltage Protection Separate single phase L/HCO units are
provided for controlling each of the three phases independently.
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Fig no 3
ASSEMBLY DRAWING OF 10 SERVO CONTROLLED VOLTAGE
STABILISER
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4. INSTALLATION & OPERATING INSTRUCTIONS
Electrical Checking & Operation
(IMPORTANT – while the unit is being installed, after unpacking and Physical
Inspection it must be tested as per the TEST
PROCEDURE given below, WITHOUT CONNECTING any load to
its terminals). Please refer Fig 1, 2, 3 & 4
4.1 Open both the front Covers
4.2 Check zero error of Voltmeter and adjust its needle to zero volt if it is found to
be displaced
4.3 Connect Mains input through the suitable wires/ cord to the INPUT terminals
provided in the lower front portion of the unit. Ensure proper earthing by using
suitable each wire connecting the earth terminal marked E to the proper
ground/earth available
4.4 Switch ON the mains input supply to the unit. The line indication lamps will
light up
4.5 Keep the AUTO/MANUAL switch S4 in AUTO position and INPUT OUTPUT
selector switch S1 in INPUT position to measure and read the input voltage with
the help of voltmeter provided on the panel In case of 3-phase unit a set of two
rotary cam switches S1 & S5 – used to select and to measure the desired line
voltage
The INPUT – OUTPUT Selector Switch S1 select and feeds the INPUT or
OUTPUT line voltage to the LINE SELECTOR Switch S5 which in turn select and
feeds the desired line voltage to the voltmeter in order to measure it
4.6 Turn the Voltmeter Selector Switch to OUTPUT position Switch ON the
Miniature Circuit Breaker MCB)
4.7 In case, the input voltage is within the specified range, the desired and rated
voltage (s) will be available
In case, the input voltage is lower/higher than the specified input voltage range
the corresponding LOW/HIGH limit indicating lamps will light up & the output
voltage will be lower/higher than the specified desired output voltage and in
proportion to the input voltage
- 14 For 3-phase SCVR with protection against phase-reversal, if the unit does not
energise within specified input range & under balanced supply voltage
interchange any two input supply wires for correct phase sequencing
4.8 The SCVR unit monitors corrects and maintainers the output Voltage
automatically when the AUTO/MANUAL Selector Switch is in AUTO position
4.9 The output voltage can be increased/decreased manually by pressing the
corresponding INCREASE/DECREASE push switches when the AUTO/MANUAL
selector switch is in MANUAL position
To test and verify this feature, proceed as per the test procedures given below
4.9.1 Turn the AUTO-MANUAL Selector Switch in Manual position and the
INPUT-OUT Voltage Selector Switch in OUTPUT position
Pres the INCREASE push Switch. The Servo Motor starts and moves the
variable transformer carbon brush the anticlockwise direction whereas the Output
Voltage goes on increasing
When the variable transformer carbon brush reaches the extreme anticlockwise
position the low limit micro switch MS operators Servo Motor stops and the LOW
limit lamp lights up
4.9.2 Turn the AUTO-MANUAL Selector Switch to AUTO position. The Servo
Motor starts thereby causing the carbon brush to move in the clockwise direction.
The low limit Micro Switch MSI returns to its normal position and LOW limit
indication lamp switches off
4.9.3 Similarly turn the AUTO-MANUAL Selector Switch again to MANUAL
position and press the DECREASE push switch. The servo motor starts in the
opposite direction thereby causing the carbon brush of the variable transformer to
move in the clockwise direction, whereas the output voltage goes on decreasing
When the carbon brush reaches the extreme clockwise position the HIGH limit
micro switch MS2 operates servo motor stops and HIGH limit indication lamp
lights up
(In case this position the output is less than 180V the limit indication neon lamp
may not light up as it requires 180V or more to make it light up In actual practice
the HIGH limit indication lamp will be required to light up when the output is more
than the desired level (i.e. 220/230V) hence the input will be more than specified
range)
4.9.4 Turn the AUTO-MANUAL Selector Switch to AUTO position. The Servo
Motor starts thereby causing the carbon brush to move in the anticlockwise
direction. The high limit micro switch MS2 returns to its normal position and the
high limit indication lamp switches off. When the desired output voltage is
attained, the servo motor stops
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4.10 The output voltage may be increased/decreased if desired by turning the
OUTPUT-ADJUST potentiometer in the clockwise/anticlockwise direction with the
help of test procedure given below: 4.10.1 Turn the OUTPUT-ADJUST potentiometer through 30 deg in the clockwise
direction keep the AUTO-MANUAL Selector Switch in MANUAL position and
press the DECREASE push switch and release it when the O/P voltage has
decreased by about 10V lower than the specified voltage
4.10.2 Again turn the AUTO-MANUAL Selector Switch to AUTO position the O/P
voltage gets corrected to a level higher than the specified output voltage
4.10.3 Similarly turn the OUTPUT-ADJUST potentiometer in the clockwise
direction and the AUTO-MANUAL Selector Switch in the MANUAL position Press
the INCREASE push switch and release it when the O/P voltage has increased
by about 10V higher than the desired voltage
4.10.4 Again turn the AUTO-MANUAL Selector Switch to AUTO position. The
corrected O/P voltage so obtained is lower than the O/P voltage obtained at step
4.10.2
4.10.5 Now turn the OUTPUT-ADJUST potentiometer through the required angle
of rotation in the desired direction and repeat the above referred procedure in the
order to set and keep the O/P voltage to the specified required level automatically
4.11 Switch OFF the mains input supply to SCVR and connect your equipment
and/or other load to the output terminals of SCVR through the suitable Wires/cord
4.12 Again Switch ON the mains input supply to the SCVR and check to ensure
that the output voltage is at the desired level
CAUTION
1. Always keep the AUTO-MANUAL selector switch in AUTO position in order to
ensure that the O/P voltage is maintained at the desired level
2. The OUTPUT-ADJUST should not be normally disturbed from its desired
position
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MAINTENANCE
This unit doesn’t require any regular maintenance However carbon brush of the
variac should be checked occasionally. If required it should be replaced by a
fresh one given as spare in moveable arm of the variable transformer
In case, carbon gets deposited on the conducting surface of the variac it should
be cleaned up after disconnecting the main input supply
If the unit is working well in the MANUAL mode i.e. the O/P voltage can be
decreased/increased by pressing the DECREASE/INCREASE push switches but
does not maintain the O/P voltage constant and at the desired level in AUTO
mode then replace the plug – in electronic – control circuit P.C.B
A Fault Diagnostics flow chart is enclosed at Fig 5 for trouble shooting various
faults
In case the equipment is still not performing satisfactorily then call our service
engineer giving details of the defects observed in order to ensure prompt and
immediate attention.
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YES
S.C.V.R.
NO
Check Mains
Supply At
Terminal Strip
No
P.R1.No
PLUG TO MAINS (230V)
MAIN INDICATOR
ON
NO
CHANGE RGB
IT IS WORKING
CHECK VOLTAGE
At S/S Tx.IT IS OK
YES
YES
Yes (SEC NO)
NO
O/P ON
YES
CHANGE
S/S Tx
Check voltage
at relay or
contacter point
Check voltage
At M.C.B. point
NO
YES
NO
Check voltage
At Variac
YES
NO
Check voltage
At Power Tx.
YES
REV
DRN
CHD
Appd
Issue
Date
CHANGE
RAVI
NO OF
DATE
E C O NO
SIGN
FAULT DIAGONISTICE S.C.V.R
SERVO ELECTRONICS
OKHLA PHASE-2, NEW DELHI-20
4.9.95
DRG NO 95149
- 18 -
Fault Diagnostic Tree – I
NO OUTPUT
Check MCB ON
& O.K Vi between
100-290
Proceed as per
F.D.Tree - II
IF Vo
Our of
range
Check Voltage
at the I/P of
Contactor
Vo=230+oV
Vi <100
Or
Vi>290
IF Vo = 0
Wait for I/P
Voltage to Come
within range
Check Voltage
at the O/P
terminal ofsr
Transformer
IF O.K
Check contactor
coil Voltage 230V
Press instant
start switch
IF No
IF still
not on
Check for
Voltage at
The instant
start switch
IF No
IF Yes
Replace contactor
Coil
IF Yes
Check Timer
&
Timer Coil
Replace the
contactor PCB
Or replair /
Replace cut
Off PCB
Terminal Strip
Or
Transformer is
burnt
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Fault Diagnostic Tree – II
No Requlation / Abnormal Out Put
Check O/P Variation
in manual mode
Check whether
S/S transformer is
defective
(Check I/P & O/P)
Replace the
control PCB
IF Yes
Replace the
sensing
Transformer
IF NO
Check whether
Motor is not –
ating or not
IF NO
In switch off
condition check
moment of
motor shaft
Replace the
motor
IF Yes
Check Defective
Motor / Variac
Gear
Replace the
Gear
IF Yes
IF NO
Check Proper
carbon brush
moment over
variac surface
IF Not
proper
Replace carbon
brush or moving
arm
IF
proper
Check moving
& fixed contact
or flexible wire
IF OK
IF Not
OK
Replace the
contacts
flexible wire
Check moving
& fixed contact
or flexible wire
Replace
RC Network
Trace out
I/P To S/S
Transformer
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ASSEMBLES & COMPONENTS (LIST)
1. Control Panel
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
Sensing Transformer
Voltmeter (0 – 300V for 0-500V for 3
Auto Manual Switch (2 Way 2 Pole)
Input/Output Selector Switch for Voltmeter
Phase Selector Switch for Voltmeter
LED input Indicators
Control PCB with Connector
Cut – off PCB
Low/High Indicators
Push Switch (increase/decrease)
Potentiometer for output adjustment
2. Main Unit
a) Dimmer (Variac) Assembly: i)
ii)
iii)
iv)
v)
vi)
vii)
b)
c)
d)
e)
f)
g)
Servo Mot
or
R/C Network
Micro Switch
Gear assembly (Motor/Variac Gear)
Variac
Variac Coupling Plate
Series Transformer
Contactor
MCB
Change-over Switch
Timer
Push Switch to bypass Timer
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S.
No
123-
456-
78-
91011-
REV
DRN
CHD
Appd
Issue
Date
CHANGE
D.K.
NO OF
Part
No
123ab456ab78abc91011abc-
DATE
Part Name
Qty
Bakelite plate 65
Motor with gear
Motor fitting ha/wa
Hexa bolt&nut ¼ X ¾
¼ plane & sp wash
Micro switch
Micro switch clam
Mic. Sw. assmb. h/w
6vaX1/4 scr & nut
6va pl & st wash
Earthing tag
Mic. Sw. clamp ass
3/16 X1 che head s&n
Plane washer
Star washer
R.c.net work
Earthing tag
R.c.n.w. ass. h/w
1/8 X ¾ sc & nut
1/8 pl.was&st.w.
1/8 cheese heads
1 no
1 no
E C O NO
SIGN
SUB ASSLY. 10_S.C.V.S.
SERVO ELECTRONICS
OKHLA PHASE-2, NEW DELHI-20
11.8.94
DRG NO 94094
4no.e
4no.e
2no
1no
Rema
rks
stand
4no.
4no.
6no.
Stand
1no.
3no.
1no.
1no.
5no.
Stand
Stand
2no.each
2no.each
5no
- 22 -
Note : Setting of trimpots VR1(LOWER RANGE) VR2(HIGHER RANGE) for
Adjusting output accuracy cannot be set at site. These adjustments need
specials jigs and are factory set.
12 PIN CONNECTION DETAILS
PIN No
1
2
3
4
5
6
Connection
Sensing
supply
AC(16y)
Sensing
supply
DC
Adjustable pot
Gnd (ne utral)
Pin No
7.
Sensing
supply AC (16)
Control
voltage (24V)
AC
11.
8.
9.
10.
12.
Connection
Relay supply
Rev
Change
Control voltage
supply (24V)AC
Drn
Ravi
Relay supply
Moter control
supply
N.C.
Chd
Appd
Moter control
supply
Date
No.of
E co no
Date
Sing
COMPONENT LAYOUT PC BC-720
SERVO ELECTRONICS
Issue
OKHLA PHASE- 2, NEW DELHI-20
3.9.96
DRG No. 95138
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