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Categories >> Engineering >> Electrical Engineering
 


 

 
Question
What is OLTC in a transformer, specify its fuction.
 Question Submitted By :: Electrical Engineering
  I also faced this Question!!      
Answer Posted By  
 Answers were Sorted based on User's Feedback
Answer
# 1
OLTC MEANS ON LOAD TAP CHANGER
THE FUNCTION OF OLTC IS TO CHANGE THE VOLTAGE LEVEL OF
SECONDARY SIDE OF TRANSFORMER ACCORDING TO CHANGE IN LOAD
TO MEET THE REQUIREMENT AND TO KEEP THE VOLTAGE CONSTANT
WITHIN THE LIMITS 

Is This Answer Correct ?    402 Yes 36 No
sriman
 
Answer
# 2
OLTC MEANS ON LOAD TAP CHANGER. THE LOCATION OF OLTC IN
TRANSFORMER IS IN HV WDG. THE TAPPING IS TAKEN FROM HV WDG
B COZ
1. IN HV WDG NO. OF TURNS ARE MORE. SO,VOLTAGE REGULATION
IS GOOD.
2. THE HV WDG IS NEARER TO THE CORE. SO, THE TAPPING IS
POSSIBLE.
3. IN HV WDG CURRENT CARRING CAPACITY IS LESS THAN LV WDG.

THE FUNCTION OF OLTC IS TO GIVE CONSTANNT VOLLTAGE TO
SECONDARY WDG.

PLEASE GIVE ANY ANSWER THEN WELCOME
ANY DOUBT E MAIL ME. ON SABALE.DNYANESHWAR@GMAIL.COM 

Is This Answer Correct ?    160 Yes 36 No
sabale.dnyaneshwar@gmail.com
 
 
Answer
# 3
hi Sabale.dnyaneshwar

ur answer is partly correct.
always LV winding is close to the core so that less
insulation can be provided b/w core & winding,
and the tappings are always on H.V(outer side of the core) 

Is This Answer Correct ?    86 Yes 9 No
sailaja.k
 
Answer
# 4
Onload Tap Changer (OLTC) is used with higher capacity
transformers where HT side voltage variation is frequent
and a nearly constant LT is required. OLTC is fitted with
the transformer itself. Multiple tappings from HV windings
are brought to the OLTC chamber and conacted to fixed
contacts. Moving contacts rotates with the help of rotating
mechanism having a spindle. This spindle can be rotated
manually as well as electrically with a motor. Motor is
connected in such a way that it can rotate in both the
directions so as to rotate the OLTC contacts in clockwise
and anticlock-wise direction. Two push buttons are fitted
on the LCP (local control panel) to rotate the motor and
hence the OLTC contacts in clockwise and anti-clockwise
direction. This movement of contacts thus controls the
output LV voltage of the transformer. So rotating of OLTC
contacts with spindle or push buttons in this way is a
manuall process. In case this process of rotating the OLTC
contacts and hence controlling the LV side voltage is to be
done automatically then a RTCC (Remote Tap Changer
Controller) is installed with the transformer HT Panel. The
RTCC sends signals to LCP and LCP in turn rotates the motor
as per the signals received from the the RTCC 

Is This Answer Correct ?    74 Yes 3 No
jitendra pawar
 
Answer
# 5
OLTC MEANS ON LOAD TAP CHANGER
THE FUNCTION OF OLTC IS TO CHANGE THE VOLTAGE LEVEL OF THE
SECONDARY SIDE OF THE TRANSFORMER ACCORDING TO CHANGE IN
LOAD SIDE TO MAINTAIN THE CONSTANT VOLTAGE WITHIN THE LIMITS
AND ALSO ITS A SAFETY DEVICE. 

Is This Answer Correct ?    40 Yes 17 No
krishnasingh
 
Answer
# 6
All answers are correct and more closely the answer No.3.
However, i am not comfortable with the fuction of the OLTC
described here in the forum:

The function of the OLTC (On-load-tap-changer) is to
maintain/regulate the output voltage of the transformer.
(This is general answer).

Technically, we are trying to change the winding turns
ratio (N2/N1) to change the mutual induction between the
two (or may be 3) windings. 

Is This Answer Correct ?    23 Yes 9 No
tse-wang
 
Answer
# 7
Sabale dnyaneshwar's Answer-3 is absolutly Right
100% 

Is This Answer Correct ?    35 Yes 25 No
mohd. karim
 
Answer
# 8
Onload Tap Changer (OLTC) is used with higher capacity
transformers where HT side voltage variation is frequent
and a nearly constant LT is required. OLTC is fitted with
the transformer itself. Multiple tappings from HV windings
are brought to the OLTC chamber and conacted to fixed
contacts. Moving contacts rotates with the help of rotating
mechanism having a spindle. This spindle can be rotated
manually as well as electrically with a motor. Motor is
connected in such a way that it can rotate in both the
directions so as to rotate the OLTC contacts in clockwise
and anticlock-wise direction. Two push buttons are fitted
on the LCP (local control panel) to rotate the motor and
hence the OLTC contacts in clockwise and anti-clockwise
direction. This movement of contacts thus controls the
output LV voltage of the transformer. So rotating of OLTC
contacts with spindle or push buttons in this way is a
manuall process. In case this process of rotating the OLTC
contacts and hence controlling the LV side voltage is to be
done automatically then a RTCC (Remote Tap Changer
Controller) is installed with the transformer HT Panel. The
RTCC sends signals to LCP and LCP in turn rotates the motor
as per the signals received from the the RTCC


OLTC(on load tap changer)is a mechanism used in transformer
for changing the tapping position on primary side(HV)of
transformer.For any installation mostly in industrial areas
and rural areas the voltage on HV of the transformer will
not be 11kv(taking an example of 11kv System)and
correspondingly the output will not be 433v.To maintain a
constant 11kv/433v the tap changer on the Primary/HV side
of the transformer is either raised or lowered to maintain
constant 11kv input to transformer.Normally it is raised or
lowered in steps of 2.5% of normal KV value. 

Is This Answer Correct ?    10 Yes 1 No
varun rekhi
 
Answer
# 9
A transformer tap is a connection point along a transformer
winding that allows a certain number of turns to be
selected. By this means, a transformer with a variable
turns ratio is produced, enabling voltage regulation of the
output. The tap selection is made via a tap changer
mechanism 

Is This Answer Correct ?    7 Yes 1 No
bhagya
 
Answer
# 10
OLTC(on load tap changer)is a mechanism used in transformer
for changing the tapping position on primary side(HV)of
transformer.For any installation mostly in industrial areas
and rural areas the voltage on HV of the transformer will
not be 11kv(taking an example of 11kv System)and
correspondingly the output will not be 433v.To maintain a
constant 11kv/433v the tap changer on the Primary/HV side
of the transformer is either raised or lowered to maintain
constant 11kv input to transformer.Normally it is raised or
lowered in steps of 2.5% of normal KV value. 

Is This Answer Correct ?    8 Yes 3 No
shreenidhi
 

 
 
 
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