Installation of Danfoss 250Kw VSD's, Fire Pump Upgrade
Project Overview:
Micron Group, in collaboration with Danfoss and Dexus, delivered a critical upgrade to the fire pump system at 100 Mount Street, North Sydney. The project aimed to eliminate the 1500-amp high inrush current affecting Fire Pumps 1–3 through the installation of three 250 kW Danfoss Variable Speed Drives (VSDs).
Under the direction of Dexus RFM, Mr Edward Zwickl, the scope encompassed comprehensive power analysis, engineering design, and system integration to ensure full compliance with Australian fire standards.
Outcome:
The upgraded system now operates with reduced current demand, improved energy efficiency, and enhanced electrical safety—providing long-term reliability and performance for one of North Sydney’s landmark buildings.
Analysis Phase:
Our detailed investigation identified significant electrical disturbances caused by high inrush currents during fire pump startup. These current spikes led to increased power demand, voltage instability, and mechanical stress on the building’s electrical infrastructure.
Micron Group performed an extensive power quality analysis, measuring inrush currents, voltage drops, and harmonic distortion using advanced monitoring equipment. The data confirmed that Variable Speed Drives (VSDs) were the optimal solution to stabilise current draw, enhance system efficiency, and improve long-term equipment reliability.
Design Phase:
Following the analysis, Micron Group engineered a customised variable speed drive (VSD) solution integrating three 250 kW Danfoss drives to optimise fire pump performance. Danfoss was chosen for its proven reliability in high-amperage, mission-critical applications and compatibility with the existing building infrastructure.
The system design ensured seamless communication between the new drives and the fire control network while maintaining full compliance with Australian fire and electrical safety standards. This approach provided precise control, improved energy efficiency, and long-term operational stability across the fire pump system.
Installation Phase:
The installation phase involved a complete on-site setup and the provision of all specialised equipment required for the upgrade. Micron Group completed the mechanical installation of the 250 kW Danfoss VSDs and installed custom support structures to manage high-current cabling safely and efficiently.
Heavy-duty, fire-rated, EMC-screened power cables were installed to ensure maximum safety, compliance, and system integrity. The drives were then commissioned and thoroughly tested under varying load conditions to confirm stable operation and performance.
Special focus was placed on integrating the building’s fire signal with the new VSD control system, ensuring seamless coordination between the drives and fire panels for full safety functionality and compliance with Australian standards.
Equipment Used:
To meet strict Australian fire safety standards, Micron Group installed heavy-duty galvanised ladder trays and Unistrut supports from EzyStrut to provide robust and compliant cable management. Flame-resistant Category 6 power and control cables supplied by Firesense were selected to maintain operational integrity during fire conditions and ensure maximum system resilience.
The installation incorporated Danfoss FC102 HVAC 250 kW variable speed drives, delivering reliable and energy-efficient power management for the building’s fire pump system. Together, these components provided a durable, compliant, and high-performance electrical infrastructure tailored to the site’s demanding operational requirements.
Reducing Peak Demand and Saving Money:
The installation of Danfoss variable speed drives (VSDs) significantly reduced the building’s peak electrical demand, improving overall energy efficiency and system stability. By controlling inrush current and optimising motor performance, the upgrade prevented costly demand spikes that can trigger utility penalties.
This optimisation not only enhances electrical reliability but also delivers measurable long-term savings, reducing operating costs and improving the building’s overall energy performance rating.
The Results Speak for Themselves:
Post-installation testing confirmed a major improvement in system performance. The fire pump network recorded a substantial reduction in high inrush current — decreasing from approximately 1500 amps (direct-on-line start) to a controlled rise not exceeding 320 amps. This represents an improvement of around 80%, achieved through precise programming by Micron Group’s engineering team.
The upgraded system now operates with minimal harmonic distortion and voltage fluctuation, resulting in a far more stable and reliable electrical network. The reduction in electrical stress on automatic transfer switches, cables, and circuit protection equipment has enhanced overall safety, extended component lifespan, and improved operational efficiency — ensuring the building’s fire protection system performs flawlessly when it matters most.
Feedback from Dexus and the Building Operations Team:
The response from Dexus and onsite operations staff was overwhelmingly positive. They reported smoother fire pump startups with no sudden electrical spikes, extended lifespan of key electrical components due to reduced inrush stress, and enhanced system safety and reliability.
End-users also praised the seamless integration of the fire signal into the VSD network, which delivered full safety compliance and operational efficiency without any system downtime during installation.
Conclusion:
This project successfully resolved the longstanding high inrush current challenges at 100 Mount Street, North Sydney, transforming the fire pump system into a safer, more efficient, and fully compliant operation. Micron Group’s engineering precision, in partnership with Danfoss and Dexus, ensured exceptional performance outcomes while maintaining uninterrupted building operations.
The result is a robust, energy-efficient fire protection system that reflects Micron Group’s ongoing commitment to innovation, reliability, and engineering excellence in critical building infrastructure.
