About Us

Our Journey

The origins of Fortress Resistors date back to the foundation of the Electroswitch brand in 1976 in Newcastle, NSW. The Electroswitch brand was created by four pioneers of the Australian electrical industry who had previously worked at Crompton Parkinson before they ceased local manufacturing in 1967. Electroswitch grew to become the leading Australian manufacturer of high-power resistors.

From 1980 Fortress Security Pty Ltd was a manufacturer of trapped key interlocking products owned by the UK listed Halma Group PLC. Halma also owned a resistor division which included the internationally recognised brands of Post Glover and Cressall. In 1990 Fortress Security began importing Post Glover Neutral Earthing Resistors for sale in Australia and New Zealand. The business grew and in 1994 Fortress Security purchased the Electroswitch business from Ampcontrol Group. The manufacturing operation was moved to Braeside in Victoria and combined into the Halma Group resistor division. In 1998 the company name was changed to Fortress Systems Pty Ltd to reflect the increased importance of the resistor business.

In 1995 Telema purchased the Halma Group resistor division, excluding Fortress Systems Pty Ltd.

In February 2009 Fortress Systems was purchased by Post Glover Resistors. At the same time, the interlock division of the company was separated out and retained by the Halma Group PLC. At this point, Fortress Systems became known as Fortress Resistors. Founded in 1893, Post Glover is the leading provider of power resistor products in North America.

Since 2009 Fortress Resistors have invested in new manufacturing equipment to bring in house the majority of processes required to manufacture sheet metal electrical enclosures and power resistors.

Fortress Resistors is now dedicated to the manufacture of power resistors and associated products.

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Quality Policy 

Fortress Resistors is committed to supplying products and services which meet the requirements and specification stated or implied, of its customers, while ensuring all products comply with required electrical standards and other legal obligations. Fortress Resistors quality system is certified by DNV to ISO9001 and ISO45001.

It is the responsibility of everyone within the company to ensure the quality of our products by following the policies and procedures detailed in the Quality Plan. Fortress Resistors is committed to supplying products and services which meet the requirements and specification stated or implied, by its customers while ensuring all products comply with required electrical standards and other legal obligations. This is achieved through the operation of a Quality Management System to a standard which satisfies ISO9001 and ISO45001.

The company is committed to a process of continuous improvement through the use of the Quality Management System.

We do this to:

  • Enhance customer satisfaction;
  • Improve financial performance;
  • Increase productivity; and
  • Encourage innovation.

This also ensures the ongoing development of:

  • Employee expertise;
  • Product performance;
  • Engineering capability;
  • Production methods; and
  • Business systems in a cost effective and efficient manner.

A key objective of continuous improvement is to ensure a profitable and sustainable company that provides stable employment opportunities.

Managers within Fortress Resistors must ensure that people under their supervision are trained in, know, and understand all aspects of their roles as well as the quality policy and procedures. The Quality Management System covers the processes of definition, development and the review of the knowledge and skills required for each aspect of the business.

Occupational Health and Safety

Fortress Resistors is committed to providing and maintaining, so far as is reasonably practicable, a working environment, including off-site activity, for employees, contractors, customers and visitors, that is safe and without risk to health.

Our overall objective is to prevent workplace illness and injury. Fortress Systems is committed to continual improvement of the OH&S Management System and OHS performance through its measurement, communication and monitoring activities.

In order to meet safety objectives Fortress Resistors has established an OH&S Management System in compliance with the ISO45001 Standard.

We will strive to achieve our overall objective, on an ongoing basis, by:

  • Complying with all relevant OH&S legislation, applicable industry standards, customer requirements, OHS Regulations, codes of practice/compliance codes as well as other requirements related to the OHS hazards as a result of our operations.
  • Establishing, reviewing and communicating Fortress Resistors’s safety objectives and targets that are measurable to all levels in the organisation. The objectives and targets are monitored on an ongoing basis and reviewed during the management review meetings.
  • Identifying and reducing the risks of all types of work activities that have the potential to produce personal injury or occupational illness. Hence, all staff and contractors are encouraged to report all workplace hazards, incidents, near-misses and accidents to the relevant OH&S representative.
  • Focusing on ongoing improvement in the areas of safety education, accident prevention, hazard management, injury prevention, incident and near-miss reporting, rehabilitation and health preservation.
  • Providing and maintaining plant and systems of work in a safe manner.
  • Ensuring appropriate information, instruction, supervision, communication, consultation, induction and training are provided to all staff and contractors prior to commencement of work, and ensuring all employees and contractors are aware of these resources and participate proactively in the above.
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Electricity Generation and Distribution

Our neutral earthing resistors are used in distribution networks to protect transformers and generators in substations across Australia and overseas.

We supply filter resistors that help to improve network quality as part of Static VAR compensation packages and damping resistors for HVDC links.

We have supported the introduction of new technologies such as Rapid Earth Fault Current Limiters (REFCL) by designing and building customised mobile test equipment to validate their installation and ongoing operation.

We support generator manufacturers and hire companies by providing customised neutral earthing resistors including contactors or disconnectors. We supply load banks for commissioning and testing, or to ensure the generator maintains a set minimum load high enough to prevent its engine being damaged.


Fortress Resistors have been heavily involved in the mining industry since our inception. We regularly contribute to the development of Australian Standards for the mining industry and support mining safety organisations such as MESA.

Our neutral earthing resistors are used in a wide variety of applications from low voltage underground substations to 66kV NERs in surface mining substations. They are used on both fixed and mobile equipment.

Our motor control resistors are used to assist the operation of draglines and shovels across the world, and for starting large conveyors and crushers on iron ore mines. Our dynamic braking resistors are used to assist the control of equipment powered by variable speed drives including conveyors, stackers, reclaimers and ship loaders.

We provide large capacity high voltage load banks to support the operation of remote power generation stations. We provide high current AC and DC contactors used as shorting contactors in liquid resistance starters and to control the operation of draglines.

Renewable Energy

Our neutral earthing resistors are used to limit the earth fault level at the substation between the primary plant and the transmission network on wind and solar farms. Filter resistors are used to help the same sites meet their power quality obligations before they can be connected to the national grid. We supply motor starting resistors and high current AC and DC contactors for motors at hydro power stations.

Data Centres

We supply customised portable load banks for commissioning and testing the power supply and cooling systems for data centre isles prior to the installation of racking and computers.

We supply large HV and LV load banks, both resistive and reactive, that are used for commissioning and testing on site generation.


Our neutral earthing resistors are used in substations at the majority of defence bases across Australia. In most cases they have been built to comply with arduous defence specifications.

We provide fixed and portable load banks for periodic testing of generators.

In collaboration with our sister company in the UK we can provide highly specialised fan forced or water cooled braking resistors that are used to rapidly brake the propeller shaft on naval warships.

Oil and Gas

Our neutral earthing resistors are used to protect gas turbines generators and transformers in all of Australia's LNG production plants. They are also used on offshore production platforms and to support upstream production infrastructure in Queensland's coal seam methane provinces.

Some of the largest neutral earthing resistors ever manufactured have been installed on the 132kV distribution systems at LNG facilities in Western Australia and the Northern Territory.

We provide dynamic braking resistors that are an integral part of linear rod pumps used to extract coal seam methane gas from wells in Queensland. We provide large capacity high voltage load banks to support the operation of remote power generation stations.


Fortress locally manufacture fan cooled braking resistors that will be used on Victoria's newest fleet of trains. We can supply specialised transit specific contactors for on board rail vehicles.

Fortress Resistors are the Australian manufacturing unit of the Telema Group. Telema are a global leader in their fields of operation which includes braking resistors, auxiliary heaters, on board contactors and disconnectors, breakers and protection relays for the railway market in addition to cooling fans for our forced ventilation applications.

Not sure what you're looking for?

Fortress Resistors offer a wide range of products and services and are happy to provide advice to assist you to make the right decisions for your application. If you need help adapting a product to suit your needs, advice on complying with applicable standards, or if you can’t find the information you’re looking for, send us an enquiry or give us a call. One of our team will get back to you promptly.

Manufacturing resistors for Australia and New Zealand