DC Gate switch

[woodchucker]

Some of you have seen that I made my own blast gates and switches to turn on my vac system.

Well, a couple have given me problems occasionaly. I thought it was the brass not touching the rub strip due to being bent. That turned out not to be the case. It was sawdust blocking the bar...

Today I replaced one with a magnetic switch (reed switch) normally used for home security systems... I didn't want a micro switch as it might be finicky getting it right. The magnetic switches NO are perfect. I had 2 one NO Normally open, and one NC Normally closed. I used the NO..

The nice thing is that the magnet just has to get close and it turns on. so it's on... not worried about topping out.

So just thought I would give you a heads up. I might do one for the DC too.

[Bob La Londe]

You mean NO shelf state right? In the business we call them NC. (Only in the alarm industry. LOL.)

Pretty common. I have a couple hundred of them in my service truck. Anybody want to buy an alarm company? LOL.

[woodchucker]

I mean when the magnet is not there it is NO normally open. When the magnet comes close the circuit is made.

[Bob La Londe]

Yep, that is NO shelf state. The alarm industry does everything backwards. LOL.

Makes it a pain to order contacts sometimes depending on the source.

[Lew Hodgett]

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"Bob La L> You mean NO shelf state right? In the business we call them NC. > (Only

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---------------------------------------------- "Bob La L> Yep, that is NO shelf state. The alarm industry does everything > backwards. LOL.

--------------------------------------------------- If you want to add to the confusion, the machine tool automation industry defines the above as follows:

NOHC: Normally Open, Held Closed when actuated.

To complete the possible limit switch position definitions:

NCHO: Normally Closed, Held Open when actuated.

SFWIW, the more nasty the environment, the more likely you are to see MOLS (Magnet Operated Limit Switch) in service.

Automated foundries are a classic application. There are 200-300 MOLS on every line. (Those were nice orders when we got them.)

The sand creates an abrasive environment that will destroy typical mechanical limit switches long before the warrantry expires.

Lew

Lew