Sorry I wasn't more clear. I wanted the valve to go to a known position under failure, but I didn't need an actual fail 'safe'.
The UPS only needs it to power this actualtor for a few seconds to get it to postion, then engage a break.
PABW
I am using a UPS for the failsafe. A mechanical spring was available, but the actuator/mount size would increase more then I wanted for the space I had. (I think they size the spring first - then the actuator) I noticed that Exlar now has this actuator on the web. It's called a Tritex. They also...
This actuator uses a continuous duty servo motor - not an intermittent motor. It's 'on' continuously, and moves with speeds up to 8 inches a second. (Which is why we used it on our turbine.)
Actuators like this are pretty costly, since they need a separate amplifier to ‘drive’ the motor via a...
ScottyUK,
Just to clarify - the actuator we are using on the fuel valve has a roller screw, not a ball screw. My understanding is that ball screws for valve control is not a good idea for the same reasons you stated - reliability.
The fuel valve actuator has a separate drive, not self...
ScottyUK
We have been using the electric actuator on our turbine fuel valve for over 10 months now. Since it does operate in essentially the same small area, I was concerned about thread wear, which we will check in October. So far we have seen no change in performance, and have been very...
I talked to my rep once again, and he mentioned that the actuator is a roller screw, not ball screw, so there is never a single point of contact on the threads, but a large contact surface area that is evenly distributed. I've considered the others you mentioned but am very intrigued by this...
The data provided to me was based on the life of the roller screw, not the servo motor,and expressed in inches of travel not hour of operation. (Somewhere near 5 million inches) It's a 2 inch actuator.
PABW
Hi,
I have a sliding stem valve application where running air will be difficult. I’m thinking of using a linear electric actuator similar to what we have on our turbine fuel valve. (Ball screw, or roller screw I think – we replaced an old hydraulic 10 months ago) My only concern is thread wear...