Hi jstein,
There is one additional item that you might want to consider regarding the “release time” of your solenoid. All of the previous posts regarding the use of a diode across the coil winding to quickly suppress the back EMF voltage (and drop-out time) in the coil during turn-off are...
It should also be noted as skogsgurra has alluded to; that a suppression resistor placed in series with the free-wheeling diode will improve the drop-out time of the magnetic circuit.
controlnovice,
You have stumbled into a vast area of engineering. The tuning of real-time, closed-loop controllers can be as much art as science. You are doing the right thing in asking for help before trying the “tweak-and-see” method of achieving stable, crisp control. In actuality, Fuzzy...
Hi Warpspeed,
A very quick calculation of your application shows that for the parameters that you have described:
NI = 5,700
Diameter = 140mm (5.5 in)
Air-Gap = 1.6mm (0.063 in)
will definitely produce a magnetic field that would drive any common low-carbon steel well into saturation, which...
Hi megahurts,
Companies like Tra-Con ( www.tra-con.com/ ) and MasterBond ( www.masterbond.com/ ) have specialty epoxies for the specific purpose of being good thermal conductors. These epoxies are the encapsulation method of choice for PCB’s, solenoid coils, and any other application where the...
Hi BRIS,
What you are basically describing is a device called a "Velocity Fuse". I don’t believe I’ve ever seen anything in the size or capacity that you need, but a quick search on google produced 826 references. Start there and you may find someone or learn how to solve your problem. Good...
Rayclag,
From the information that you have provided so far, a proportional solenoid actuator could provide what you are looking for (25 lbs force and 0.4 inches of linear stroke – correct?) in a package size that would probably be competitive with a motor/gear-train solution. Motors certainly...
Bootstrap,
Your friend’s objective is to build a proportional, bi-directional solenoid to position something like a valve spool with +/- 0.25 inches of linear stroke – correct? The design of solenoids and solenoid actuators is really as much art as science. From what you have described, it is...
OperaHouse is right on target. DC solenoids do not experience the "in-rush" current that an electro-magnetic AC device will encounter. AC solenoids will experience an in-rush current due to the eddy current effect and the change in reluctance (and thus inductance) of the magnetic...
Hi Greg (uswt),
If you have difficulty finding a proportional actuator for your project, I may be able to help you configure something that will work. I’m assuming a stepper is out because of the need for a full-retract mode of operation in the event of a power loss – correct?
Hi tmox,
It sounds like you have a very interesting project. I have developed several multi-cylinder lifting systems (synchronous-lifting) for a variety of industries, and the problems I encountered are identical to those you have described. I have seen several lifting-system applications...
Hi hhumble,
Sensing the speed of a turbocharger could be a very difficult task. My main concern is that the high temperatures involved could fry any sensor in a short period of time. From my limited experience in working with speed pickups used in diesel engines (engine RPM that is), I can...