M350 Starter

For use with low and medium voltage wound rotor motors from 200kW to 750kW, maximum rotor volts = 1500 V

Overview

The M350 is a 2 stage liquid resistance starter, each stage replacing the equivalent of approximately 5 stages of fixed resistance. The resistance units comprise electrodes (either 2 or 3) immersed in electrolyte, contained within a 350 litre stainless steel tank. The number of electrodes used is determined by the kW rating of the motor, the number of starts per hour and the run-up time. The principle of operation is based on the difference in resistivity between the liquid electrolyte and its vapour contained in an electrode chamber.

The passage of the initial rotor current causes immediate partial vaporisation of the electrolyte and instantaneously adjusts resistance and starting torque to optimum value. During run-up, the thermal interchange which occurs decreases the resistance and a timed contactor then short circuits the low residual resistance. The progressive decrease in resistance provides smooth and continuous acceleration, hence the motor reaches full speed in the shortest possible time with the absence of mechanical stress. As the resistance decreases in direct relation to the motor speed, the possibility of operator misuse is minimised and motor burn-out problems are resolved.

Flexibility

M350 starters are easily adjustable on-site to meet changes in torque or load. This is achieved by altering the electrolyte strength.

Environmental Stability

A layer of oil is floated on top of the electrolyte to form a seal which not only minimises evaporation, but eliminates contamination from the atmosphere. In locations with severe dust conditions such as mines, quarries and rubber mills laden with carbon black, no additional protection
is required.

Climate Conditions

Whether in the snow fields, or the desert regions of the outback, M350 starters are operating almost maintenance free. Their only requirement is the need to occasionally top them up with drinking water (pH = 7 to 9) every 12 months or so.

Availability

For ratings up to 750 kW very quick deliveries can be achieved as all components required for construction are available ex-stock.

M350 Ratings

M350 starters are designed to meet the starting torque requirements of the application and the starting duty (starting time and starts per hour) specified by the user. The ratings given to M350 starters are therefore variable and application dependant.

Notes: Nominal ratings only, based on 4 consecutive starts followed by 2 starts per hour from hot.
- Actual ratings will depend on start torque and run up time required.
- FLT = Full Load Torque otherwise refered to as Motor Rated Torque