Frequently Asked Questions

What is Lrs?

Also known as Liquid Rotor Starter, Liquid Rheostat Starter & electrolytic starter

what is electrolyte?

A liquid that an electric current can pass through. 

For LRS the Water + Na2CO3 will be act as an electrolyte. 

what should i add in water to prepare electrolyte of lrs?


Sodium carbonate (also known as washing soda, soda ash and soda crystals)

does the water quality determine the life of lrs?

Yes, Low-quality water and high contamination can reduce the life of electrodes as well as LRS tank.

how to prepare the electrolyte?

Dissolve Na2CO3 (washing soda) in drinking water (approximately pH 7) with the proportion 5 to 30gm / litre in a separate tank/bucket. Stir the solution and pour the solution into the LRS tank. The pH of the solution has to be between 9 to 11.

The quantity of Na2CO3 and pH value is depends on the following:

1) Torque requirement of the connected load on the motor shaft

2) Ratio of Rotor Voltage/Rotor Current

3) Area of electrodes (Model of LRS)

4) Water quality

5) Starting time

What should be the ph of lrs electrolyte?

Between 9-11

It depends on the requirement of starting torque.

how do i measure the resistance of electrolyte?

By applying the AC voltage between fix and moving electrodes.

how do i measure the conductivity of electrolyte?

The conductivity meter can be used to measure the conductivity in siemens per metre (S/m).

The Conductivity of electrolyte is to be adjusted depending on:

1) Conductivity of natural water used to prepare electrolyte

2) Starting torque requirement

3) Starting time

4) Nature of connected load to the motor

what may be the reason for the mill to trip on start up?

Due to high conductivity

Why dose the mill accelerate very slow?

Due to low conductivity

Why dose the lrs electrolyte heat up?

Due to low conductivity

dose the lrs electrolyte temperature plays important role in starting?


What type of maintenance activity is required to keep the Liquid Resistance Starter in top working order? 

General maintenance primarily consists of topping up the electrolyte with potable water, greasing/lubricate the electrode moving mechanism (chain, sprockets, bearings, gearbox, etc) and making sure all mechanical and electrical connections are tight. This type of work is normally conducted annually or as needed.

Can we use SPRS (Slip power recovery system) with pioneer lrs ?

Yes, PIONEER LRS can be made in a such a way that it can be directly interface with the SPRS system.