Overspeed protection

[veggie]

Bruce,

What bout using an automotive electric door lock solenoid?
I've seen them in some auto parts stores for $20.


Veggie

[dubbleUJay]

Guys, what is the downside of shutting/keeping the exhaust valve closed for emergency shutdown?
More or less like an exhaust brake on a truck, but would it stop completely without damaging parts?
Probably a wacky idea, but I'm thinking a "resettable break-away type exhaust push-rod" of some sort

Now how stupid does this "thinking outside the box" idea sound? 

dubbleUJay

[BruceM]

The problem with door lock solenoids are that they are designed for a very short duty cycle.  It takes about a minute for my 6/1 Listeroid to come to a complete stop.  A door lock solenoid wouldn't take that for long, I don't think.   

A an auto window opener assembly (motor, gearbox) would have enough power, I think.

[veggie]

The problem with door lock solenoids are that they are designed for a very short duty cycle.  It takes about a minute for my 6/1 Listeroid to come to a complete stop.  A door lock solenoid wouldn't take that for long, I don't think.   

A an auto window opener assembly (motor, gearbox) would have enough power, I think.

But perhaps a door lock solenoid could pull a pin on a spring loaded linkage which shuts the rack.
Would only need to be energized for 1 second.
The linkage would have to be manually reset after the shutdown cause is investigated.

Veggie

[BruceM]

For just pulling a pin, there are plenty of solenoid choices, and the door lock solenoid would be one of them.  You'd want to use a 555 timer and MOSFET to activate the solenoid.  The the emergency signal (oil, rpm, temp, vibration, etc.) can be continuous while the solenoid only gets a brief pulse.