Improving productivity, saving energy, cutting costs

With rising energy costs, products offering energy savings are becoming increasingly important. To help businesses reduce energy usage, Motortronics has developed a range of energy saving products.

The vast majority of electric motors in use today are fixed speed, fixed voltage AC induction motors. These motors consume two thirds of the total electricity used in industry. With this in mind, using a technology that could save energy on fixed speed induction motors should be a consideration when replacing motor starters or designing new systems.

How it works

Motortronics’ energy saving system works by reducing the current and iron losses of a motor not running at full load. The energy savings will depend on a number of factors including the efficiency of the motor and the load.

Motortronics Soft Starters will also save businesses money by reducing the electrical and mechanical strain placed on applications – resulting in less ‘down time’ and maintenance cost on electrical circuits, gearboxes, belts and associated mechanical components.

iERS is a technology that monitors the voltage, current and power factor during the start of a motor and then uses this information to ensure the motor runs efficiently under all load conditions.

iERS - How It Works
iERS - How It Works

When any AC induction motor becomes lightly loaded, the power factor and the efficiency decrease. This is caused by the inherent design of the motor and the laws of physics, and leads to energy being wasted. These are known as excitation losses.

iERS continually monitors the power factor, recognizing when the motor is becoming lightly loaded and then instantly employing strategies to reduce the losses by controlling the voltage and current supplied to the motor to match the load conditions. This not only increases the part load power factor, but reduces the energy consumption in kW.

When the motor becomes fully loaded, the power factor increases, and iERS automatically bypasses itself to ensure the most efficient use of energy in all motor load conditions.

See this example of the energy savings that could be made using Motortronics’ energy saving system:

90kW Motor Running at 100% Load

90kw motor running at 100 percent load

90kW Motor Running at 20% Load

90kw motor running at 20 percent load

90kW Motor Running at 20% Load with energy saving motor controller

90kw motor running at 20 percent load with energy saving motor controller

Savings Calculator

The annual savings amount that could be achieved for a 1.8 kW per hour reduction is shown in this table.

The price of electricity is calculated using a value of £0.13 per kWh.

% Time
Part Load
Annual Hours
at Part Load
kWh Saving Annual Saving
40% 3,494 6289 £818
60% 5,241 9434 £1226
80% 6,988 12578 £1635

The above is a worked example; every application is different and will generate different levels of savings.

Existing Direct On line (DOL)/Across the Line or Star Delta Installation

Installing our soft starter will reduce the downtime and require less maintenance

The payback is fast and will provide you with additional benefits:

  • The Lower inrush current of Soft Starting reduces mechanical stress and minimizes penalties from the utility company.
  • Extending system lifetime due to reduced mechanical wear on:

    • The Motor
    • Belts and pulleys
    • Gears and chains
    • Couplings and bearings and
    • Cavitation and water hammer in pumps

Reducing electrical effects:

  • Reducing the heavy current surge on the electrical supply which can be severe enough to cause voltage dips and flickering lights.
  • Pitting and burning of contacts due to high currents which are many times the motor full-load current.
  • The power cables run cooler
  • Less stress upon Electrical Distribution system


Our soft starters provide sophisticated motor protection providing additional cost benefits including Full I²t Motor Overload Protection with memory.

Enhanced protection can also provide further cost reductions:

  • Instantaneous Overcurrent (Shearpin) protection.
  • Low Current Trip / Dry Run protection.
  • Phase rotation protection to prevent reverse rotation of the motor.
  • Input and Output Phase Loss Protection to prevent damage from power disturbances.
  • Start Delay - Allowing actuators to operate before starting.
  • Advanced Auto Reset Feature.
  • Hand Auto feature for VMX-synergy™.
  • Predictive Maintenance – StartView MLink.
  • Frequency Fault.
  • Thyristor Signal.
  • Thyristor Firing.
  • Thyristor Sensing.
  • Thyristor Short Circuit.
  • Thermal Sensor.
  • Current Limit Time Out.
  • PTC Thermistor.
  • External trip.
  • Communications Failure.
  • Bypass Contactor Failure to Close and open protection.

Internal Bypass

An integral bypass is initiated at the top of ramp and reduces losses in the soft starter.

Further to this there are no harmful harmonics which can reduce the performance and reliability of other equipment connected to the grid. Motortronics Soft Starters adhere with all emission and immunity requirements laid out by the EMC directive.

Innovative features such as touch screen and automatic setup make VMX-synergy™ extremely easy to setup and use

Where to Buy

Sales Managers


Peter Boyle


Giacomo Raggi


Gemma Gaunt

Europe, Middle East, Africa & India

Motortronics UK Ltd
Bristow House, Gillard Way, Lee Mill Industrial Estate, Ivybridge, PL21 9GG, UK

T : +44 (0) 1752 894554
E : [email protected]

Asia & Australasia

Motortronics International Korea
#601, 632, Seobusaet-gil, Geumcheon-gu, Seoul

T : +82 (0) 2 867 5808
E : [email protected]

Motortronics International Korea
41, Cheoyongsaneop 4-gil, Cheongnyang-eup, Ulju-gun, Ulsan

T : +82 (0) 52 237 5805
E : [email protected]

The Americas

Motortronics Inc
1600 Sunshine Drive, Clearwater
FL, 33765

T : +1 727 573 1819
E : [email protected]


M & P Machinery & Electronics Control
32 Jiaxin Road, Jimo,, Qingdao, 266229

T : +86 53281 725028
E : [email protected]

Beijing Locensate Energy Saving Technology Co. Ltd (LV - Sales)
411 Guangyi Building B 5#, Guangyi Road, Beijing, 100053

T : +86 10 83 131799
E : [email protected]