Motorised 3 way mid position valve

[Ramendra S Roy]

Hi,

Can anyone tell me how the actuator part of a mid position 3 way motrised valve work?

Is it by adjusting the motor torque against a spring till it comes to rest in a particular position?

I am asking this primarily because I am trying to understand why my newly replaced valve actuator hums away at 50 Hz (quite loudly). The valve itself is new also and it is a Danfoss Randall HSV3 and HSA3 combination.

I really would ike to understand the working of the valve actuator. Please point me to any resources on the web - if any. That wil be aan immense help too. I have searched without too much success.

Thanks Ramendra

[MLD]

Google ***3 way valve*** These type of valves use a torque motor that nulls (balances) based on control pressure(s) and (in control systems) some form of feedback. This site might help: