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Question
what is GRR(Grid Rotot resistance)?Why it is used beside of 
LRS?
 Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
GRR(Grid Rotot resistance) is a resistance box which is
used for speed control of slipring Induction motor & save
the power.The Induction motor having high starting torque
needs resistance in rotor circuit by the use of GRR we can
add the resistance in the circuit & increase the slip so
torque, ones motor will start we reduce the resistance of
GRR by Contactor,and at full speed shott all resistance.
LRS is used where no speed control is required only high
starting torque is required.
 
Is This Answer Correct ?    74 Yes 9 No
Surya Prakash
 
Answer
# 2
It is not always true that Liquid Resistance Starter cannot
be used as spped control device. In fact it provides a
smoother speed control of induction motor that GRR as the
later is having stepped speed control.
 
Is This Answer Correct ?    28 Yes 8 No
Sayan
 
 
 
Answer
# 3
GRR(Grid Rotot resistance) is a resistance box which is
used for speed control of slipring Induction motor & save
the power.The Induction motor having high starting torque
needs resistance in rotor circuit by the use of GRR we can
add the resistance in the circuit & increase the slip so
torque, ones motor will start we reduce the resistance of
GRR by Contactor,and at full speed shott all resistance.
LRS is used where no speed control is required only high
starting torque is required.
 
Is This Answer Correct ?    20 Yes 1 No
Rajesh Ku Sahu
 
Answer
# 4
LRS GENERALLY USED FOR STARTING OF MOTOR AND REDUSE THE
STARTING CURRENT AND INCRESE THE TORQUE.GRR ALSO SAME USES
& SPEED CONTROL BY VARRING THE ROTORRESISTANCE OF MOTOR.GRR
IS AGRID RESISTANCE BOX IS CONNECTED WITH ROTOR IN
SERIES.GENERALLY THIS CONTROL USED IN Y/Y CONNECTION WOUND
ROTOR MOTORS
 
Is This Answer Correct ?    16 Yes 3 No
Mohan
 
Answer
# 5
GRS= Grid resistance STARTER
GRR= Grid resistance REGULATOR

While:LRS = Liquid Resistance STARTER
& LRR = Liquid Resistance REGULATOR

Both GRR & LRR or GRS & GRS are technically similar.

In both the equipment we are adding the resistance in the
rotor circuit.

BUT THE MAJOR DIFFERENCES ARE:

GRR a solid form of resistance, While LRR is Liquid form of
Resistance.

In GRR onece you define the resistance value, we can not
change the resistance value without changing the hardware.
While in LRR we can change the resistance value by changing
the Liquid concentration(PH).

In Regulators, the resistance is continue in circuit, hence
the temperature of resistance increase.

In solid resistance its possible to withstand the high
temperature without major changes in resitance value, while
in Liquid Resistance if temp. goes above 90 degree C, the
resistance value is change drastically.
Hence the Grid(Solid) resistance mainly used in speed
regulators.
If we want to use the Liquid Resistance as a controller,
then we need to add a heat exchange or cooling system to
maintain the Liquid temperature.


Any one can find out the more details on GRS/GRR and LRS/LRR
on www.resistancestarter.com or www.pew-india.in
 
Is This Answer Correct ?    4 Yes 0 No
Rupesh Usadadiya
 
Answer
# 6
GRR USED FOR HIGH STARTING TORQUE AND LIMIT THE STARTING
CURRENT.
 
Is This Answer Correct ?    2 Yes 0 No
Sanjay
 
Answer
# 7
GRR is a grid resistance box in which the resistance is
controlled by contactor logic as per slip ring motor
requirement and the purpose of grr is to control the speed
of motor by change the resistance of rotor circuit and save
power.LRS(Liquid rotor starter)is used for starting of slip
ring induction motor only . in lrs we use water with soda
for add the resistance and the ph value should be 9-11
 
Is This Answer Correct ?    1 Yes 0 No
Ashish Chouksey
 
Answer
# 8
GRR it is may be resistance box it is the speed controlable
device and power saving device it is slip ring induction
motor Or rotor resistance motor

When Resistance Decereases speed increases
when resistance increases speed Decereases
 
Is This Answer Correct ?    1 Yes 0 No
Arun Kumar.k
 

 
 
 
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