Liquid Resistance Starters
These are used for inserting external resistance in the rotor-circuit of slip ring induction motor at the starting to reduce starting-current and increase starting - torque used in various industries and installations like cement plants, rolling mills, pumping plants, sugar mills, paper plants.
These liquid rotor resistances are applicable with both motor operated or manually operated mechanism. these give step-less cutting of resistance and are economical in comparison to wire wound or grid -resistances. we also manufacture stator - rotor panels.
Liquid Rotor Resistance Starters
It will be having MS Electrolyte tank, floor mounting, free standing type, dust & vermin proof construction. It will be provided Fixed & Moving electrodes made-out by MS Sheet Steel having horizontal movement, Anti-corrosive Epoxy black paint (inside the electrolyte tank walls), Phase barriers of polypropylene, Mechanism box, Power/Shorting Contactor/Cable Box and all other accessories for motorized as well as manually operation. Integral Control Box of suitable size (housed with main MS tank of LRS) will be provided & it having RDOL Starter of suitable rating Aux. contactor for reversing & forwarding Pilot motor & Moving electrodes, Over load relay, Key actuated Auto/Manual selector switch, Push button, Isolating switch, Indicating lamps, Power/Control TBs & necessary back-up protection etc. It will have Interlocking arrangement/circuit for Stator control panel, so that, Main motor can not be started unless resistance is in fully ‘IN’ Position. It will be provided AC3 duty Air Break Power contactor of ‘Reputed make’ (in delta connected) to suit the RA of motor for final short-circuiting the resistance when motor attains full speed. It will have provision for Manual operation, also.
- The Liquid Rotor Resistance Starter conforms to BS-140.
- It is totally Automatic Motor Operated and also, having Manual operation with the help of hand wheel.
- Electrolyte Tank will be made-out by MS sheet steel of 3mm to 5mm thick and other fabrication will be made-out by 2mm thick MS Sheet Steel.
- Epoxy Black Paint (for Anti-corrosion) will be done inside the Electrolyte Tank.
- Movement of Moving Electrodes will be Horizontal type.
- It is suitable for two consecutive starts from cold & four starts per hour equally spread in hot conditions.
- Limit Switches for Interlocking purpose with spares contacts will be provided.
- Moving & Fixed Electrodes will be made-out by MS Sheet Steel (zinc plated) of 3mm to 5mm thick.
- Electrolyte filling & over flow sockets will be provided.
- Air Break Power Contactor (AC3 duty) of ‘ABB/BCH/L&T make’ will be provided in delta connected to suit RA of motor for Final short-circuiting.
- Integral Control Box of suitable size (housed with the Main MS Tank of LRS) will be provided. It will have RDOL Starter having suitable rating Contactor for Forwarding & Reversing Pilot Motor & Moving Electrodes, Over Load Relay, Key Actuated Auto/Manual Selector Switch, Push button, Isolating Switch, Indicating Lamps & Power/Control TBs.
- Pilot Motor of ¼ HP Squirrel Cage type of reputed make will be provided.
- All the Switch-gear components will be of reputed make.
- It will be suitable for interfacing with consignee’s Stator Control Panel.
- Standard time of resistance cutting is depending upon the rating of motor. This time can be suitably changed to suit Main Motor.
- The Interlocking arrangement will be provided for Stator Control Panel. The Interlocking is such that the Main Motor can not be started unless Resistance is fully “IN” position & the Main Motor will be Tripped, if the Electrodes does not reaches to Run Position within specified time.
- Painting will be done by Hand Spray Gun M/cs with Light grey 631 of IS:5.
- Necessary cable glands and lugs can be provided at an extra cost.
- Electrolyte/Water level indicator & Temperature indicator cum controller with alarm & trip contacts will be provided at an extra cost.
- In the event of ordering all related drawing like GA, BOM & Schematic diagram etc. will be submitted for getting approval before start manufacturing work.& procuring of major Switch gear items of reputed make.
Vapromatic Type Liquid Rotor Resistance Starters
Construction of Vapromatic Type Liquid Rotor Resistance Starter :
The LRS (V) is a rectangular tank having electrolyte in it and works on the principle of resistance cutting based on different resistivity of electrolyte at different temperatures. The tank will be constructed from heavy gauge sheet steel and have enclosure protection of IP-42. The electrodes will be of zinc passivated M.S. suitably supported with insulator and bushings to sustain stress at the time of external faults. The fixed electrodes are mounted at the bottom of the tank and adjustable electrodes will be mounted at the top of the electrolyte tank through insulating bushing. The inside surface of the electrolyte tank will be painted with anticorrosive epoxy paint Polypropylene phase barriers will be provided to prevent circulating current between the electrodes. Also the metallic resistance used for bringing the motor from 80% speed to rated speed would be mounted in a separate chamber which would be able to dissipate the generated heat The tank will have accessories e.g. drain valve with brass plug at the bottom, separate plug for filling of electrolyte etc. Painting will be done by Hand Spray Gun M/cs with approved paint shade.
Main supply will be of 415 Volts and control supply for LRS (V) will be 230 or 110 Volts and accordingly contactor coils would be of 230 or 110 Volts only. Initial position and full speed position indicating contactors each having 2N0 and 2NC potential free contacts will be provided for sequence interlocking. Electrolyte level and temperature sensor with alarm and trip contacts will be provided for sequence interlocking.
The LRS (V) will be complete with ample sized cable box and will be suitable for termination of PVCIXLPE Aluminum conductor cable. The terminal box will have detachable gland plate.
Control Panel having Switch-gear Components as :
- Temperature and Level Sensors.
- Initial and Final position contactors with multiply contacts.
- Two nos. of Electronic Timers of : Reputed make', one for adjusting the time for Motor to reach up to 80% speed and other one is used if final shorting contactor is not operated after predetermined interval.
- Adequate rating and quantity of Step & Final Power contactor of :Reputed make' for smooth cutting of resistance and for final short-circuiting.
- Control Transformer (415V/230 or 110V) with control fuses Of required. Indicating Lamps (LED type) and TBs.
Interlocking for LRS (V):
- Motor would be ready for starting in RFS (Control Supply Healthy. Temp. within Limits).
- Zero Position (RFS, both shorting contactors in un-operated position)
- Final Position (If motor shorting not done in predetermined interval)
The Potential Free Contacts are required for Interlocks with:
- HT/LT Panel : HT/LT to Trip & Start Signal
- DCS : LRS (V) Healthy. Resistance IN/OUT. Liquid Level Low, Liquid Temp. High
Indications (with LED type Lamps:
- Ready to Start
- Zero Position
- LRS (V) in Service
- Liquid Level Low
- Liquid Temperature High
Terminal Blocks : All LRS (V) units will be provided with separate Terminal Blocks for termination of wires for External Connections.