How the Modern SER Drive boosts grinding performance

Modern mill operators in mining and mineral processing require a specific range of mill speed to achieve the best grinding performance and reduce mill liner wear. 

Thank you for reading this post, don't forget to subscribe!

With the latest generation technology and significant investment, CSE Uniserve created the Modern Slip Energy Recovery (SER) Drive which offers extensive speed control and no synchronous speed dead band.

Designed for the single or dual motor Semi-Autogenous Grinding (SAG) mill market, this new technology addresses all mechanical, electrical, environmental and cost concerns.

Delivering unmatched SAG Mill speed and power

Sub and hyper synchronous mill motor speed control is offered without speed deadband.  The SER delivers 100 per cent of rated (nameplate) motor shaft power at above synchronous speeds, an exclusive benefit of this SER technology.

The CSE Uniserve Modern SER Drive.
The CSE Uniserve Modern SER Drive is a compact, powerful, multi-functional and reliable addition to other SAG mill control technologies on the market today.

Electrical features

The CSE Uniserve Modern SER is designed, manufactured and tested to the ISO 61800 family of standards, meaning you can be sure it will operate in almost any site or location around the world.

An energy efficient solution, the SER works to reduce overall power consumption across the plant through inbuilt efficiencies and clever design, which can also remove the need for other capital costs and equipment.

Power Factor control is built into a Modern SER and can be designed to include Power Factor Correction requirements of the wider plant.  Our Modern SER also features active VAR recovery circuit, which again can be sized to include other equipment.

The recovery transformer helps achieve low inrush currents through pre-charge and TCHD (Current Harmonic) is typically only 3-5 per cent.   Modern SER technology combines these benefits with low ongoing operational and maintenance costs and so can easily claim to offer the most cost-effective solution for a new mill or existing plant upgrades using Wound Rotor Motors.

Production performance

In another exclusive benefit, the CSE Uniserve SER design includes purpose-built Liquid Resistance Starter (LRS), permitting us to offer automatic and manual bumpless bi-directional transfer and dedicated, repeatable, high torque, low impact mill starting.  This feature, along with ‘frozen charge’ detection and management ensures longevity of the mechanical drivetrain.

Our Modern SER also provides redundant mill operation, also known as hot redundancy.

The exclusive benefit of hot redundancy – the instant process correction when a failure is detected – is that it reduces the chances of mill downtime, providing a much higher level of confidence around programmed outputs – an advantage particularly attractive to operators in remote areas.

Other key features to boost production performance include bi-directional motor rotation capability and as you would expect, the Modern SER also features field bus connectivity and remote dial in for ultimate control, on or off site.

Installation benefits

Manufactured using IGBT liquid to air heat-exchange platform, our SER transfers heat outside the switch room and so requires very little ongoing air conditioning, again saving maintenance and ongoing electrical load.  Due to this and its IP54 construction, our SER does not require cubicle ventilation and so has no ongoing dust load issues.

Designed around an extremely small footprint and with no rear access requirements, our SER is ideal for containerised solutions.

A typical 6MW drive is only W 5400 x D 800 x H 1920mm.


As mines and comminution move further away from modern cities, to harsher climates and higher locations, the ability of a Modern SER to operate successfully at elevation and in extremes of temperature permits organisations to focus on developing and producing resources, no matter the location.

The CSE Uniserve SER boasts a wide ambient operating temperature range of -40 to +55C and can operate to an altitude to 5,000m.

Offered as standard with a stainless-steel frame and galvanised plinth, for those sites which may require, it we offer a fully stainless-steel cubicle.

High power ratings

CSE Uniserve’s Modern SER Drive offers robust mill control, lower energy use and higher power ratings than other mill drive technologies.

It is the only mill controller with the ability to offer 100 per cent motor torque at hyper-synchronous speeds for single or dual motor mills up to 22MW, an exclusive benefit no other technology can match. It also returns unused power when operating below 100 per cent speed.

Someone once said, “with great power comes great responsibility” and so the design includes an ability to include specific speed and torque requirements, ensuring the longevity of mechanical components such as gearboxes and couplings.

Lower operating costs

The Modern SER can be installed and run for less when considering associated infrastructure, direct housing and overall power consumption.

The specific benefits of lower-cost design – through reduced need for supporting the plant, lower energy usage, minimal air-conditioning, smaller switch rooms, frozen charge management, inbuilt Power Factor and harmonic control – all result in lower ongoing running costs and improved grinding control.  With effective and very fine speed control and no dead band, operators will be able to better control the grind and extend the life of mill linings.

Demonstrated savings

Mill designers and owner/operators will benefit from significant infrastructure savings due to the small footprint, vastly reduced cooling requirements and the potential to eliminate further harmonic and power factor correction mitigation.  With no dust load and reduced air-conditioning, ongoing maintenance is greatly reduced.

Further production savings will also be realised with finer speed control, no speed deadband, full motor torque, even at hyper synchronous speeds and frozen charge management. Finally, the inbuilt hot redundancy delivers production certainty to operators in the unlikely event of the SER failing.

Plant retrofit and ‘drop-in’ solutions 

With the ability to containerise the SER, ‘drop-in’ solutions are realistic and viable.

The technology exists to build new or refit older plant utilising Wound Rotor Induction Motors (WRIM) with the most modern, up-to-date and future-proof solutions.

Investment paybacks of less than 12 months are possible for existing sites presently using variable speed LRS on energy savings alone.

Your solution to finer grinding control

The Modern SER Drive is a compact, powerful, multi-functional and reliable addition to other SAG mill control technologies on the market today.

The Modern SER’s lower-cost design, achieved through the reduced need for supporting plant – combined with its lower energy usage and exclusive design benefits results in lower ongoing costs, increased reliability, finer grinding control and production efficiencies.

To discuss how the Modern SER Drive can benefit your operations, get in touch today.