Operating principle of Vapromatic type LRS

This is based on the difference in resistivity between a liquid electrolyte and its vapour, contained in an electrode chamber.

The passage of the initial rotor current causes immediate partial vaporization of the electrolyte and instantaneously adjusts resistance and starting torque to optimum values. During the run-up to speed, the thermal interchanges which occur progressively decrease the resistance.

A limited contactor then short circuits the low residual resistance. The starting torque is determined according to the requirements of the driven machine or the current limitation.

Electrical Characteristics……………………………………….

– Rating up to  10MW

– Rotor voltage between slip rings:  4500 V maximum,

– Integral short circuit contactor: 50 A – 2050 A,

– Number of electrode assemblies: Depends on ratings

– Connection : One to four stages,

– Cabling via drilled gland plates,

– Delay time : Programmable timing control

Electrolyte…………………………………………………………

– Electrolyte temperature thermostatically controlled,

– Electrolyte level: overflow spout,

– Universally available Na2CO3 & water solution used as electrolyte.

Tank……………………………………………………………………

– Tank capacity: Depends on rating and requirement

Environment………………………………………………………..

Protection IP 54

Presentation………………………………………………………

– Resin polyester based textured powder coated color shed finish.

-Thickness: 80 microns minimum

 IS631 0R RAL 7032 OR RAL 7035

-Average weight with contactor

   -without electrolyte:…. kg

   -with electrolyte: … kg

Accessories:

• Top and Bottom Electrode set

• Phase barrier set

• Insulators

• Logic controller

• Power contactor’s contact kit

• Temperature and Level switch

Optionals:

• Circulating pump (Electrolyte mixer)

• Slip/buffer resistors (useful for Crusher/chopper, etc)

• Heat exchanger for high number of starts (electrolyte-water or electrolyte-air)

• Anti freeze heaters in tank

• Motor Power (KW)

• Rotor Voltage (V)

• Rotor Current (A)

• Motor rated Speed

• Type of Driven machine

• Single or Twin Drive

• Load Torque curve of driven machine

• Desired number of starts per hour

• Starting torque and starting time

Please specify special requirements, if any.

To start the slipring motors of following:

• Milling (Cement mill, Ball mill, Vertical Roller Mill, hammer mill, etc..)

• Crusher/Chopper/Shredder

• Ventilation (all type of fans/blowers)

• Pumps

• Compressors

• Conveyors

• Cement & Mineral

• Mining

• Steel

• Sugar

Do’s:

• Take the control trial first, then no load trial and after successful completion of no load trail proceed for load trial

• Use Sodium carbonate (Na2CO3) with water for electrolyte

Don’ts:

• Don’t use caustic soda (Sodium hydroxide / NaOH) to prepare the electrolyte.