WA Lane Farming – Walsall Wood
Danfoss FC202 Aqua Drive FC202 37kw IP55 + 0-16 bar Transducer.
WA Lane contacted us regarding a problem with their bore hole pump application. We had already supplied 2 off 15kw Danfoss FC102 drives to control extract fans in their potato stores.
The application involved supplying water at a stable pressure to a ring main around their field to which a mobile watering system latches onto at various hydrants.
Originally they had a 45HP borehole pump with a 15HP booster motor at their pump station. They upgraded the borehole pump to a 50HP (37kw) with the intention of getting rid of the 15HP booster motor. Thus controlling the 37kw with an inverter to maintain constant pressure.
The aim was to simplify the system and get more accurate pressure control.
They were using an old Murphy gauge together with low and high pressure switches which did not give them accurate control of pressure. They were experiencing water hammer when to booster motor and borehole pump started and stopped. Also they had to tweak the pressure switches daily to enable smooth running of the system.
One of the main problems was the impact from losing pressure then regaining the pressure on the plastic pipes maintaining the water ring main. This increase and decrease in pressure caused the pipes to expand and contract which caused leaks.
The solution offered was:
Supply a Danfoss FC202 Aqua Drive 37kw. An IP55 enclosure to mount onto the existing pump house wall next to the pump supply. A Danfoss 0-16 Bar transducer with a 4-20mA feed back to the inverter for pressure control.
We set the drive in closed loop to maintain a 10 bar pressure, introducing the FC202 sleep mode function. This mode allows the drive to go to sleep when pressure had been reached but enable fast reaction times when the pressure dropped.
We incorporated a live zero option into the Danfoss FC202 parameters to stop the drive if the transducer control signal was lost. This being important because if the signal from the transducer drops below 4mA the drive would speed up to max 50 Hz which could create an over pressure issue in the system.
The transducer is used to enable a very accurate control of pressure. The FC202 will maintain 10 bar pressure very smoothly without the spikes from repeated star delta or DOL motor starting.
We choose the Danfoss FC202 Aqua Drive because of the dedicated parameters within the drive for water applications.
Previous annual electric costs were up to £10,000.
The pump, when running is currently working at approximately 47 Hz and 34Kw functioning at 10 bar “with” the mobile watering system pumping. There are very few leaks and the system goes to sleep when the watering system stops. We have reduced the time to prime the ring main and also reduced the labour cost from continuously “tweaking” the system.
The old ammeter used to read 75amps when pumping; it now reads a steady 60amps. Dropping to zero when asleep.
Our current estimation for savings is £5,000 per annum on electric only.
Further savings come from complete system maintenance and less mechanical stresses.
For more information about the Danfoss Aqua Drive FC202: Technical Documentation
More Danfoss Inverter drives products available here.