Compact liquid-cooled AC drive is more versatile

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Combining high-power performance with a space-saving design, the new Allen Bradley PowerFlex 700L liquid-cooled drive from Rockwell Automation is claimed to deliver unrivalled application versatility. Its high-performance, energy-efficient liquid-cooled technology enables it to be installed in conditions where air-cooled drives may increase climatic control costs or where they simply could not operate, such as dusty locations.

Potential applications include pumping applications, oil field machinery, marine propulsion, forming and stamping, log carriages, lathes, mining, centrifuges, HVAC/chillers and many others. Thanks to its liquid cooling, the PowerFlex 700L also requires far less floor space than conventional air-cooled drives, which further increases the product's application versatility.

According to Rockwell Automation, unlike other liquid-cooled drives that require a coolant line to each insulated gate bipolar transistor (IGBT) power transistor, the PowerFlex 700L features a single cooling input and output to the IGBTs. This proprietary liquid-cooled heatsink greatly increases power density, resulting in a drive that is up to 65 per cent smaller than similarly power-rated air-cooled drives. The simplified coolant system makes it easier for users to integrate the drive coolant supply with existing systems, such as recycled plant water, or, if required, to incorporate a water-to-air heat exchanger loop to dissipate drive heat into the air.

Quiet and clean

Available in power ranges from 150-860kW, the PowerFlex 700L features IGBTs instead of diodes in its AC to DC converter section. This provides the drive with an active rectifier that enables regenerated energy – commonly occurring in high-power applications such as presses and centrifuges – to be safely returned to the facility's power system, thereby boosting energy efficiency. Regenerative energy is actively modulated to avoid harmonic disturbances, making the drive one of the quietest in the industry. The PowerFlex 700L's active rectifier technology reduces power line harmonics to levels below IEEE 519 and CE requirements without installing additional hardware.

The active rectifier provides the PowerFlex 700L with the ability to boost and regulate the drive's DC bus voltage, thereby minimising the effects of input voltage disturbances and power line dips – and helping to protect sensitive processes. This technology also provides a power line voltage boost that enables the drive to control a single voltage motor on both 480 and 380V power lines. This flexibility is particularly beneficial to OEMs building machines for the international market.

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