LIQUID RESISTANCE
MOTOR STARTERS
Slipring Motors upto 5000 KW.
ŸSALIENT FEATURES
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Robust and Non-Flammable construction.
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Simple in Operation.
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Provides smooth and stepless cutting of resistance in rotor circuit of
the Motor, reducing Starting Current and increasing Starting Torque of
Slip-Ring Induction Motor.
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Requires Minimum Initial Investment and Negligible Maintenance.
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Available in various sizes for motors upto 5000 KW.
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Designed to give equal resistance in each phase with special profile of
Fixed and Moving Electrodes.
Need cheap and simple solution of Sodium Carbonate (Washing Soda)
and water as electrolyte, thus totally eliminating the costly and scarce
insulating oil.
Provided with large volume of electrolyte for better heat dissipation
and ample cross-section of copper contacts and current carrying
parts for less temperature - rise.
Tank and Cover are of welded steel construction and provided with
Relief Vent, Filling & Over - Flow Socket, Drain Plug etc.,
Ÿ Manual or Motor Operated Mechanism.
Inner side of Electrolyte Tank is lined with FRP for corrosion resistance
to increase life of Tank.
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Poly-Propylene phase barriers are used to increase insulation level
between phase to phase and phase to earth.
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Shorting Switch or contractor is provided outside the electrolyte tank
to Short-Circuit Liquid Resistance when motor attains full speed.
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contacts and Electrodes are easily accessible for maintenance and
replacement.
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Fitted with Epoxy Cast insulators and Bushings for better insulation
and longer life.
Solid State Liquid level Controller with alarm and contacts. Dial type
Liquid level Controller with alarm and contacts.
Dial type liquid Temperature Indicator and controller with alarm and
trip contacts.
Can be supplied suitable for different modes of operations like, Local /
Remote or Automatic through Stator Switch, etc.,
Current Relay can be provided for synchronisation of Rotor Resistance
Cutting and Motor Acceleration.
distinct and clear indication of electrolyte level from outside through
Electrolyte level gauge. No need to open the cover.
Fool-Proof interlocking System is Provided by interlocking contacts to
prevent closing of Stator Switch unless full Resistance is in rotor
circuit.
Timer to trip Stator Switch is provided if Liquid Resistance is not cut
within predetermined time.
ELECTRODE SYSTEM
Moving and Fixed Electrodes are of Fabricated Sheet Steel (zinc
plated) of suitable profile and size. One set of Fixed Electrodes are
mounted on Epoxy Cast Insulators and connected to Main Terminals,
Other set of Moving Electrodes are shorted and earthed. Electrodes of
Stainless Steel can also be supplied if required.
CONTROL SYSTEM
A Control Box is provided for electrical operation, housing all Relays,
Contractors, Push Buttons, Indicating Lamps, Switches and other
necessary electrical items.
Forward and Reverse contractors with Over Load Relays are provide
to actuate the Pilot Motor. Contractors are inter loacked such that
only one Contractor can be operated at a time. Necessary
interlocking circuits are provided for the safety of Main Motor.
MECHANISM
Cable Box of sufficiently large size with Cable Gland is provided for
termination of Rotor Cables to connect Liquid Resistance to the Rotor
of Motor. For proper termination of Cables on Busing, ‘L’ Shaped
tinned Copper Terminals are provided. The Cable Box also
accommodates shorting mechanism.
SMOOTH START OF MOTOR
250
LEGEND
1 Motor Torque Speed curve
2 4 Speed Metallic Resistance curve
3 Liquid Motor Starter curve
200
3
2
Driving Mechanism is provided in the Mechanism Box containing pilot
motor, Gear Box, set of Spur Gear and pinion, transmitting power to
moving channel through a Shaft fitted with Sprocket and chain
arrangement, the Moving Electrodes are fixed to the channel fitted
with rollers moving smoothly on horizontal guide rails. During
emergency or for maintenance, the mechanism can also be operated
manually by a Hand wheel after disengaging the Motor Drive with the
help of Declutching arrangement provided To arrest the movement of
the Moving System at the end position, Oil Tight Limit Switch are
provided.
TORQUE ( % ) FLT
150
100
50
0
25
(%) SPEED
50
75
100
SPEED - TORQUE CHARACTERISTIC OF MOTOR
CABLE BOX
Liquid Resistance provide high starting resistance to rotor circuit,
cutting the resistance sleeplessly synchronizing with Motor
Acceleration to very low or negligible value near Full Load speed. This
gives a high Starting Torque and very smooth start.
The above figure shows the comparisons of Grid Resistance Start and
Liquid Resistance Start.
LIQUID SPEED CONTROLLERS
Liquid Speed Controllers can be supplied to provide required Slip
resistance to the slip - Ring Motors for speed variation Special sized
Electrolyte Tank and Heat Exchangers are provided to dissipate the
heat energy generated in electrolyte during variation of speed.
Special pump (with mechanical seal) is provided to circulate the
electrolyte continuously.
Twin Drive liquid resistance
To ensure identical acceleration of two similar motors driving single
large machine, we can supply Twin Liquid Resistence mechanically
coupled and operated by single Mechanism.
The inter connection between tanks ensures equal resistance of
electrolyte .
OVERALL DIMENSIONS
HP (KW)
TYPE
Width ‘A’
mm
Length ‘B’
mm
Wight without electrolyte
Height ‘C’
mm
Nett
Kg.
Gross
Kg.
LEGEND
IT
DESCRIPTION
350 (260)
LSH-1
1250
1450
1375
425
525
1
TANK WITH FRP LINING
650 (500)
LSH-2
1250
1650
1375
475
625
2
FIXED ELECTRODE
1000 (750)
LSH-3
125
1850
1475
525
725
3
MOVING ELECTRODE
1500 (1100)
LSH-4
1550
2050
1575
600
875
4
POLYPROPLENE BARRIERS
1800 (1300)
LSH-5
1550
2300
1575
650
1000
5
DRIVING MECHANISM
2000 (1500)
LSH-6
1650
2300
1775
700
1150
6
CONTROL BOX
2400 (1800)
LSH-7
1650
2600
2175
750
1350
7
CABLE & CONTRACTOR BOX
3000 (2300)
LSH-8
1650
3150
2275
900
1600
8.
WATER LEVEL INDICATOR
4000 (3000)
LSH-9
1750
3800
2375
950
1750
9
DRAIN PLUG
1950
10
GLAND PLATE
6700 (5000)
LSH-10
1850
4300
2875
1025
OUR OTHER PRODUCTS
OIL IMMERSED SYSTEMS
ROTOR STARTER
AUTO TRANSFORMER STARTER
STAR - DELTA STARTER
OIL CIRCUIT BREAKER
NIE/FLPMTR/0308
STATOR ROTOR STARTER
Power House, # 18, J.C. Road, Bangalore - 560 002. INDIA
Tel : +91 80 42434343, 22235434 Fax : +91 80 22226666
Mail : National : sales@newindiaelectricals.com
International : export@newindiaelectricals.com
Site : www.nielgroup.com / www.newindiaelectricals.com