Power restrictions have been removed from wind turbines at England's largest onshore wind farm, at Fullabrook Down near Ilfracombe in Devon.
A 50MW cap on power produced by the 22 turbines has been lifted so they can produce full power of 66MW.
The aim is to allow noise testing at 12 sites by North Devon District Council after concerns were raised.
If the turbines come within noise limits the wind farm will be fully operational.
Owners Electricity Supply Board said it would be "some weeks" before results were known.
The 110m (360ft) turbines are said to be capable of producing enough electricity to meet the needs of about 30,000 homes in north Devon.