HVAC systems now a reality

The group’s Siemens Building Technologies Division has just introduced the G120P variable speed drive for HVAC systems.

Various user-friendly functions ensure high energy efficiency and safety, while keeping operating costs low. Thanks to protection classes IP54 and IP55, the G120P variable speed drive can also be used under harsh environmental conditions.
 
The Siemens G120P variable speed drive is suitable for applications that require an economical, energy-efficient and easy-to-operate drive for pumps or fans. It operates in a power range from 0.37 to 90 kilowatts.

The device has a modular structure, consisting of a control unit, the power module and an operating panel or a blanking cover.

This design enables individual components to be exchanged without having to replace the entire drive. For example, a power module can be exchanged without reconfiguring the entire device or rewiring the signal and bus cables.
 
A high protection class, either IP55 or IP54, allows the variable speed drive to be used under harsh environmental conditions at temperatures up to 60°C, for example for controlling the speed of fans and recirculation pumps in heating and cooling systems. The new variable speed drives replace the Siemens SED2 devices.
 
The G120P variable speed drive is tailored to the needs of pump installations and ventilation systems and therefore offers numerous safety features. The device can routinely detect different events such as overloaded motors, pumps that are blocked or have run dry, blocked fans and cracked belts, and respond to them immediately, for example by shutting down the pump or fan, triggering an alarm or starting a predefined process.

When used in ventilation systems, the G120P automatically switches to emergency mode in the event of a fire. As a result, the overpressure generated by the ventilation is retained as long as possible, and the escape routes remain smoke free.

The G120P has various functions that improve energy efficiency for operating HVAC applications and systems economically. For example, the device is characterised by very low apparent power.

Because the drive automatically switches to main operation at nominal speeds, it can cut energy consumption by as much as three percent. In addition, the variable speed drive has a low impact on the power grid and meets the IEC/EN 61000-3-12:2011 standard without additional components such as line reactors.

A comprehensive fan, filter and motor monitoring system is integrated into the device to avoid loss of HVAC plant and rising operating costs. Flow optimisation in U/f mode and during vector control adapts the motor magnetisation to the partial load of the pump or fan. This helps increase motor efficiency under partial load, which substantially increases the efficiency of the overall system.