Home>Plant, Process & Control>Compressors and ancillary equipment>Hertz Kompressoren UK launches HSC D direct drive air compressor range

Hertz Kompressoren UK launches HSC D direct drive air compressor range

02 July 2013

The HSC-D direct drive, variable speed rotary screw compressors cover kW outputs from 22kW to 315kW.

Because the motor shaft directly drives the compressor unit without the need for additional parts, such as belts, the compressors offer a particularly compact design. The direct drive transmission system also affords impressively quiet operation at a lesser dB level at peak load compared to belt driven models. A further benefit of the direct driven system is that vibration levels are considerable decreased, contributing to reduced wear & tear, greater longevity and a longer timeline between routine maintenance and service schedules.

Energy efficient properties

Furthermore, due to the direct drive compressors’ ability to generate more pressurised air with less energy, there are also convincing cost-saving and environmental benefits to be had. Additional energy efficiency properties are provided courtesy of the compressors’ frequency inverter, which accurately adjust the motor speed in accordance with the required air demand of the user. Energy consumption keeps decreasing almost linearly in proportion with the capacity, reducing energy consumption by as much as 35 per cent. Also, the wide capacity ranges allow the HSC-D compressors to supply the required amount of pressure continuously and at a constant level. With these benefits, not only are additional energy savings made possible, but the potential for unfavourable pressure change effects on some critical equipment are also prevented. Another contributing factor regarding the compressors’ energy efficiency properties is their IE2 efficiency electric motors. All compressors within the HSC-D range are fitted with electric motors that meet IE2 efficiency class (motors that meet IE3 effiency class are optional). The motor safety factor has been increased to 1,2 – 1,4 with larger motors. They also offer increased radial force resistance due to a special bearing, shaft and lubrication design.

Benefit of VSDs

The HSC-D compressors’ electric motors offer high efficiency even at low speeds due to the inclusion of high-efficiency Variable Speed Drives (VSDs). Analogue outputs are included for a secondary VSD drive for fans. Additionally, the compressors include master/slave functions and a new mod-bus protocol for VSD Communication. Frequency controllers of these VSD compressors are high-quality drives featuring one brand and one Model VLT for the whole compressor series. They are very user-friendly with an easy-to-follow menu structure, and the controllers are also easy to install, with no need for any setup on the VSD drive. An additional benefit is that of the strong worldwide after-sales service.

With the VSD for the fan, a constant temperature is achievable, potentially resulting in major energy savings. The heat regime is fixed by controlling the fan revolution speed according to the airend temperature with a secondary drive. Constantly running at the airend’s most efficient temperature is achieved, resulting in energy savings on the main motor. This also results in little or no temperature fluctuations, which extends the life of all components within the Frecon compressor. Another benefits include: highly efficient cooling and extra energy saving on the fan; reduced noise levels due to the lower running speed of the fan; and extended fan life due to less mechanical stress as a result of no on/off fan operation.

The compressors are also fitted with controllers for improved functionality, reliability and a number of new functions; these include the ability to record used total energy levels. HSC-D models also feature a PID activation timer to prevent the airend from speed up without sufficient lubrication, and a PID activation temperature parameter to prevent the airend from cold speed-up.

Benefits of Soft Start

The new range of direct drive compressors also features state-of-the-art Soft Starters, as an alternative to the more traditional star delta starting method. The Soft Start system can extend the motor’s service life and avoid high start current on the energy system. With this system the motor can start as many times as required, while short idle time periods can result in additional energy savings. Additionally, the Soft Start system can minimise starting currents, eliminate current spikes and reduce voltage drops on the network. Furthermore, the system can optimise cabling and minimise inrush current with no transition spikes. In term of mechanical benefits afforded by the Soft Start system, these include: minimised stress on transmissions such as gearboxes, couplings and bearings on motor/airend; substantially reduced maintenance costs; and reduced downtime. These advantages can result in up to 35 per cent of a HSC-D Series compressor's total cost being saved after a five-year application period.