Deregulation speed ?

[tom52]

My Volvo 2020 engine manual gives an idling speed of 850 +/- 25 rpm and a deregulation speed of 3900 +/- 25 rpm.
What does deregulation speed mean ?
Is it max revs ? Under load or unloaded ?
Thanks

 

[duncanmack]

The governor should not let it exceed 3900 +/- rpm loaded or unloaded

 

[tom52]

Thanks Duncan