New high-power drives of up to 250kW are considerably smaller
20 May 2011
Danfoss has introduced new and considerably smaller housings for its VLT frequency converters with power ranges between 90 and 250kW. Depending on their output and design, the drives are up to 66 per cent smaller in volume for the same performance than the previous models. In addition, Danfoss has extended the available options for the mains input side, including fuses, a load break switch, and - in the future - a contactor.
The greatest volume saving is achieved by the 250kW VLT frequency converters. Their volume is reduced from 0.450 m³ to just 0.014 m³, making these converters among the smallest in their performance class.
Danfoss is also introducing enhancements to save customers time and money. In future, the customer will be able to choose whether to order input fuses, a load break switch or an additional contactor along with the drive. These extras - which can be incorporated on their own or in combination - are contained within a housing extension. This means a greater installation height overall whilst retaining the narrow and compact design.
Danfoss has further improved the cooling/ventilation design, allowing the user direct access to the cooling duct, which - in the new housings - also has a new ventilation module. The fan (now 48Vdc) is supplied directly from the dc link. This reduces the discharge times following disconnection of the frequency converter, which saves time if maintenance or servicing is required. The new fan is considerably more energy efficient than the previous one, which further increases the overall efficiency of the VLT.
The newly housed drives can also be fitted with a heating module to prevent the formation of condensation. This can be controlled from outside the device, according to ambient conditions, and thus only works when really needed, further reducing energy consumption.
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