In terms of the functionality of this high quality HVAC drive, the motor has built-in logic controls, able to easily alternate between the two pumps in either functioning, or stand-by duty applications. This ensures the drive timer will balance between usage of each of the pumps and using auto tuning, this intelligent device can actually monitor how the system handles rebalances made by the drive. The drive will then incorporate that data, so that corrections can be made quickly, and stable operation achieved. An ‘automated resonance monitoring’ system also helps protect against system denigration by avoiding the frequency bands that can create resonances in the ventilation system.
In terms of the efficiency of the VLT HVAC drive, you are also able to constantly monitor the drive and detect any components running at lower than perfect efficiency using its energy monitoring system, which provides detailed information on a range of energy consumption uses. Flow compensation also ensures the pressure set point is reduced according to flow, further saving energy use. Elsewhere, The PM motor support assists with any non-salient permanent magnet motors all the way up to 22 kW and as standard, the drive also comes with Automatic Energy Optimisation, increasing energy efficiency for partial loads by between 5 and 15% by optimising motor magnetisation.
As regards the safe functioning of the drive, the FC 102 is ‘ruggedised’. This simply means that the process of adding a special treatment to the components means that they will benefit from extra protection, and will also stay locked in place, even when experiencing high levels of vibration. This therefore also means that this model is perfect for mobile equipment, or even use in a marine setting. The printed circuit boards within the drive are also coated, to conform to class 3C2 – IEC 60721-3-3. If the conditions of use are expected to be particularly harsh, an additional coating can also be ordered, to bring the drive up to standard for class 3C3.
In terms of fire hazards, a safety feature of the FC102 is its fire override mode. Here, if warning signals indicate the presence of fire, the fire override mode will kick in to ensure the device can bypass the warnings and keep the fire escapes are free of smoke, thereby the device remains in operation for as long as is possible, until it ultimately fails.
Danfoss design quality
The Danfoss VLT HVAC Drive FC 102 contains many design aspects to help with the safe, smooth functioning of the drive. In terms of the pumps themselves, the drive uses internal frequency and power measurements to permanently monitor the pumps’ condition to maintain ‘dry pump protection’. Fast acceleration of the pumps can be achieved using ‘initial/final ramp’ to allow the normal ramp to take over and thereby prevent damage on thrust and bearings.
In addition, a built-in cascade controller enables the drive to use a fixed-lead pump to control up to three separate pumps. The fan belt is constantly monitored and the drive will quickly be able to detect a broken belt from the relation between current and speed. However, if there are leakages, or even breaks, the ‘end of pump curve’ will activate the alarm and then, based on what the user would like to do, take action, or simply shut off the pump.