Sleek Stabilizer for A/C Units
By
Executive Engineer (Electrical)
BSNL, Electrical Division,Tirunelveli.
Email: chalapathy@bsnl.co.in
venkatchalapathy6107@gmail.com
NEED FOR STABILIZER
1. Very high speed in growth of industries
in our country.
2. High transmission loss from generation
point to distribution point as well as more
demand compared to generation of
electrical energy.
3. Progress of new projects for generation
of power is very slow as compared to the
growth of the requirement
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4. In Urban and Rural areas the supply
voltage varies from 140 to 170 Volts .
5. All the single phase equipments are
manufactured in our country is 230 Volts
50 Hz operation only.
6. For optimum utilization, effective operation
and to improve the life of equipments, we
need stabilized voltage for all kind of
electrical equipments.
7. In BSNL, due to implementation of latest
technology, air-conditioning is essential for
various telecom equipments which needs
stabilized voltage for operation.
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GUIDELINES
Directorate’s guidelines for wide range servo
stabilizers – for Single phase
I/P Voltage range
: 120V – 280V
O/P Voltage range : 240V + 1%
Rating
: 1 – 350 kVA
Cooling
: Upto 8 kVA – Air
cooled
Oil cooled for other ratings
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SCENARIO IN TAMILNADU
Power supply received from TNEB
Voltage :
>170 volts in most rural &
urban areas
:
>140 volts in few remote
villages on rare occasions
Voltage ranges of Stabilizers in TN market
Normal range
: 170 – 270 volts
On request basis : 140 – 280 volts
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SELECTION OF STABILIZER
Servo Stabilizer
1. Motor cum transformer involved in voltage
correction. Hence More Power loss
2. Precise voltage correction is not required for our
equipments.
3. More components involved resulting in
excessive maintenance problems.
4. High Wear & Tear of winding & brushes.
5. Not locally serviceable
6. Suitable for high precision requirement
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SELECTION OF STABILIZER
Ordinary Sleek type stabilizer
1. Voltage correction with static winding & relays.
Circular torroidal core employed. Hence less
power loss & more efficiency.
2. Less components involved. Hence Simple.
3. No Wear & Tear.
4. Locally serviceable
5. Suitable for low precision requirement.
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OUR REQUIREMENT
Stabilizer is required only for Split /
Window and high sensible heat type ac
units. Hence high precision not required
Sleek type ordinary stabilizer with input
voltage range 170 – 270 volts is adequate.
In rare places, we may require 140 – 280
volts input voltage range
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Capacity of stabilizer
Split ac units
1.5 TR Split A/C units consumes
1860 W i.e. Approx 2.20 KVA to add
30% it works out 2.86 KVA say
maximum 3 KVA stabilizer needed.

2 TR Capacity Split A/C units
consumes 2385 W i.e. Approx 2.81
KVA to add 30% it works out 3.65
KVA say maximum 4 KVA stabilizer
needed.

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Capacity of stabilizer
High Sensible heat type A/C Unit


2 x 1.5 TR power consumption is
2840 W i.e. 3.34 KVA add 30% it
works out 4.34 KVA say 4.5 KVA
2 x 2 TR power consumption is
3490 W i.e. 4.11 KVA add 30% it
works out 5.34 KVA say 5.5 KVA
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Type of materials to be used for
high efficiency
 Copper
winding wire shall be of
good quality ISI Marked with ‘F’
insulation & enamel coated.
 The transformer core shall be of
laminated Torroidal Core instead
of conventional type laminated
Core [ EI type, etc ]
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Specification for 3 KVA Stabilizer
Capacity
Wide Range
Normal Range
Input Range
140V - 280V 170V - 270V
Output Range
210 – 240 V 210 – 240 V
LV cut off
140V
170V
HV cut off
280V
270V
Time Delay
2-3 Minutes
2-3 Minutes
MCB Protection (Input) 20 A SP&N
MCB
Electronic O/L Relay
6 A – 12 A
20 A SP&N
MCB
6 A – 12 A
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Specification for 4 KVA Stabilizer
Capacity
Input Range
Output Range
LV cut off
HV cut off
Time Delay
MCB Protection (Input)
Electronic O/L Relay
Wide Range
140V - 280V
210 – 240 V
140V
280V
2-3 Minutes
32 A SP&N
MCB
10 A – 16 A
Normal Range
170V - 270V
210 – 240 V
170V
270V
2-3 Minutes
32 A SP&N
MCB
10 A – 16 A
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Specification for 4.5 KVA Stabilizer
(2 x 1.5 TR High Sensible)
Capacity
Wide Range
Normal Range
Input Range
140V - 280V 170V - 270V
Output Range
210 – 240 V 210 – 240 V
LV cut off
140V
170V
HV cut off
280V
270V
Time Delay
2-3 Minutes
2-3 Minutes
MCB Protection (Input) 32 A SP&N
MCB
Electronic O/L Relay
12 A – 18 A
32 A SP&N
MCB
12 A – 18 A
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Specification for 5.5 KVA Stabilizer
(2 x 2 TR High Sensible)
Capacity
Input Range
Output Range
LV cut off
HV cut off
Time Delay
MCB Protection (Input)
Electronic O/L Relay
Wide Range
140V - 280V
210 – 240 V
140V
280V
2-3 Minutes
32 A SP&N
MCB
14 A – 20 A
Normal Range
170V - 270V
210 – 240 V
170V
270V
2-3 Minutes
32 A SP&N
MCB
14 A – 20 A
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Comparison with conventional and
Energy efficient Sleek stabilizer
Conventional
stabilizer
Transformer will be EI
core – Iron loss will be
high (Efficiency 89%)
Poor insulating material
and poor quality copper
may be used – Copper
loss will be more
Bigger in Size
Energy Efficient type
Sleek Stabilizer
Torroidal core transformer
will be used with minimum
Iron loss ( Efficiency 95%)
High quality copper with
good quality insulation will
be used – Copper loss will
be minimum
Slim and sleek
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Conventional Vs Sleek
stabilizer ( 3 kVA)
Type
Losses
Operation Kwh /
for 3 kVA hrs/day
annum
Conven- 264
watts
Tional
Sleek
model
Savings
in Rs.
12 hours
1156
kWH
5,780/-
96 watts 12 hours
420
kWH
2,100/-
736
kWH
3,680/-
Savings
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Conventional Vs Sleek
stabilizer ( 3 kVA)
Assumptions:
1. Efficiency of conventional stabilizer :
89%
2. Efficiency of sleek stabilizer : 96%
3. Energy cost : Rs. 5.00 per kWH
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Recommendations
Sl
no
1
Ac unit
Rating
1.5 TR
Stab.
Type
Sleek
2
2 TR
Sleek
4 kVA
3
2x1.5 TR
High Sens
Sleek
4.5 kVA
4
2x2 TR High Sleek
Sensible
5.5 kVA
3 kVA
I/P
Voltage
170-270
140-280
170-270
140-280
170-270
140-280
170-270
140-280
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Proposed Components Type
Component
Type
Torroidal Core for transformer Silicon Steel CRGO - M4 Grade
Winding copper wire
Enameled class “F” insulation
Insulation
Ployster Class ‘B’
Metal Chassis
Outer finish
Screws Nickel plated
Printed Circuit Board
1.0 mm thick
Powder coat, white or grey
Combi Philip Head
PCS or IC or reputed make
LED
5 mm x 2 mm Square
Electro magnetic relay
30 A - 12V/24V Single
Changeover
Electronic over load relay Range setting varies from
06 A to 20 A as per rating20
Wish you Happy
Deepavali
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Thank You
very much
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