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...

http://imgur.com/a/wLzRs#24
http://imgur.com/a/wLzRs#25

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.
--
Jeff

"woodchucker" wrote in message
...
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...

http://imgur.com/a/wLzRs#24
http://imgur.com/a/wLzRs#25

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.
--
Jeff

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.

On 4/25/2014 8:16 PM, Bob La Londe wrote:
"woodchucker" wrote in message
...
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...

http://imgur.com/a/wLzRs#24
http://imgur.com/a/wLzRs#25

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.
--
Jeff

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

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


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





--
Jeff

"woodchucker" wrote in message
...
On 4/25/2014 8:16 PM, Bob La Londe wrote:
"woodchucker" wrote in message
...
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...

http://imgur.com/a/wLzRs#24
http://imgur.com/a/wLzRs#25

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.
--
Jeff

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

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


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.


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





--
Jeff

"woodchucker" wrote:

The magnetic switches NO are perfect. I had 2 one NO Normally open,
and one NC Normally closed. I used the NO..
snip
So just thought I would give you a heads up. I might do one for the
DC
too.
------------------------------------------

"Bob La Londe" wrote:

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

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" wrote:

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