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gradual voltage

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=141870
Printed Date: March 29, 2024 at 5:27 AM


Topic: gradual voltage

Posted By: voltagexdt
Subject: gradual voltage
Date Posted: October 16, 2016 at 4:40 PM

ok, I don't even know if this can be done. I know a lot about relays.
anyhow heres the who what where

I make train horns..
now a real train horn is used with a lever.. as the lever is pulled the horns slowly grow louder as power (air) is fed into the horns.

doing my horns in a vehicle is different as I use a solenoid that is instant on.

im trying to figure out a way to slow the progression of the solenoid. its my theory that if say 9 or 8 volts is supplied to the solenoid it would open slightly.. of course it may not even work.

which in that case nothing I can do.

but basically im looking to make a solenoid into an electric ball valve so to speak. and yes the do make electric ball valves however when power is supplied the open completely regardless if you are holding the button or not... so they wont work.

any ideas would be great.



Replies:

Posted By: KPierson
Date Posted: October 28, 2016 at 8:57 PM
The problem with using a solenoid is that they are typically depend on an electromagnetic switch. This generally leaves you with either enough magnetic power to overcome the spring and open, or not enough and the spring forces it closed. I doubt with a "gradual" voltage you'll have any control at all in how much the valve opens - it will either be full open or full closed (like on a relay - you can slowly increase the voltage until it "clicks" on but you'll never see the contacts floating in the "middle".

A spring loaded butterfly valve would probably be better, but would most likely not be cost effective. with a spring loaded butterfly valve you can control the drive motor at different voltages and it will pull the valve open at a predictable ratio.


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Kevin Pierson





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