What is a "wet contactor"

B

Bob Engelhardt

Guest
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob
 
In article <p18ufl013tt@news7.newsguy.com>, BobEngelhardt@comcast.net
says...
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob
Click to expand...

Dry contacts are when there is no electrical current/voltage and the wet
ones are when you have voltage/current.

For a tach , most of the old style would have the wires across the
points. There would also be the car electrical system connected to the
points. That would make them wet. If (probably never found) there were
a seperate set of contacts that opened and closed as a shaft on the
engine turned and not connected to the electrical circuit of the car,
they would be dry contacts.

While not useful in this case, some contactors/relays/switches will have
mercury wetted contacts.
 
"Bob Engelhardt" <BobEngelhardt@comcast.net> wrote in message
news:p18ufl013tt@news7.newsguy.com...
An eBay listing for a electronic tachometer specifies that it's input can
be a "wet contactor". Is there a standard meaning for "wet contactor"?
Click to expand...

In some cases it can mean mercury wetted contacts, but the term "wetted" is
also used to describe when dry contacts carry sufficient current to break
through any oxide or contaminants on the contact surfaces.
 
On 2017-12-18, Bob Engelhardt <BobEngelhardt@comcast.net> wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?
Click to expand...

dry contacts is terminology used to describe contact frovided as part
of a device that are ot connected to any internal circuit and singnal
by chngeing from insulator to conductor,

by extension wet contacts must be switching current

I'm guessing that this wet/dry terminology is borrowed from hydraulics

In an automobiles before crank position sensors became common the tachometer
output would be taken from the ignition coil (where the points or electronic
ignition connects). There'd be a programmabile divider to compensate for how
many cylinders the engine has.


--
This email has not been checked by half-arsed antivirus software
 
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob
Click to expand...

Once again I have not told the whole story :-(

I was going to use this tach on my milling machine spindle, not my car.
I think it works by pulsing a circuit between 2 of its connector pins.
It also can be pulsed by " ... PNP or NPN proximity switch, HALL
sensor". Does that help determine what the mean by "wet contactor"?

Bob
 
On Monday, December 18, 2017 at 12:42:33 PM UTC-5, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob
Click to expand...

A french kisser!
 
On 2017-12-18, Bob Engelhardt <BobEngelhardt@comcast.net> wrote:
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob

Once again I have not told the whole story :-(

I was going to use this tach on my milling machine spindle, not my car.
I think it works by pulsing a circuit between 2 of its connector pins.
It also can be pulsed by " ... PNP or NPN proximity switch, HALL
sensor". Does that help determine what the mean by "wet contactor"?

Bob
Click to expand...

it seems that they bsically mean anything that generates a pulse every
time the shaft rotates, what sort of sensor do you want to use?

--
This email has not been checked by half-arsed antivirus software
 
On 12/18/2017 10:53 PM, Jasen Betts wrote:
On 2017-12-18, Bob Engelhardt <BobEngelhardt@comcast.net> wrote:
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob

Once again I have not told the whole story :-(

I was going to use this tach on my milling machine spindle, not my car.
I think it works by pulsing a circuit between 2 of its connector pins.
It also can be pulsed by " ... PNP or NPN proximity switch, HALL
sensor". Does that help determine what the mean by "wet contactor"?

Bob

it seems that they bsically mean anything that generates a pulse every
time the shaft rotates, what sort of sensor do you want to use?
Click to expand...

I'd like to use a magnet on the spindle and a reed switch. It's about
the most contamination proof. If the reed switch is "wet".
 
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob
Click to expand...

I asked this question of the (Chinese) seller, not expecting any real
answer. I was not disappointed: "Really so sorry. I do not know what
the problem is. I hope you can understand"
 
Bob Engelhardt wrote on 12/19/2017 1:21 PM:
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob

I asked this question of the (Chinese) seller, not expecting any real
answer. I was not disappointed: "Really so sorry. I do not know what the
problem is. I hope you can understand"
Click to expand...

Would you ask this question of the person operating the cash register at
Home Depot?

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
 
"rickman" <gnuarm@gmail.com> wrote in message
news:p1blus$lqu$2@dont-email.me...
Bob Engelhardt wrote on 12/19/2017 1:21 PM:
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet
contactor"?

Thanks,
Bob

I asked this question of the (Chinese) seller, not expecting any real
answer. I was not disappointed: "Really so sorry. I do not know what the
problem is. I hope you can understand"

Would you ask this question of the person operating the cash register at
Home Depot?
Click to expand...

One or two electrical retailers have surprised me - but discount stores are
just box shifters.
 
On Mon, 18 Dec 2017 23:44:03 -0500, Bob Engelhardt
<BobEngelhardt@comcast.net> wrote:

On 12/18/2017 10:53 PM, Jasen Betts wrote:
On 2017-12-18, Bob Engelhardt <BobEngelhardt@comcast.net> wrote:
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob

Once again I have not told the whole story :-(

I was going to use this tach on my milling machine spindle, not my car.
I think it works by pulsing a circuit between 2 of its connector pins.
It also can be pulsed by " ... PNP or NPN proximity switch, HALL
sensor". Does that help determine what the mean by "wet contactor"?

Bob

it seems that they bsically mean anything that generates a pulse every
time the shaft rotates, what sort of sensor do you want to use?


I'd like to use a magnet on the spindle and a reed switch. It's about
the most contamination proof. If the reed switch is "wet".
Click to expand...

While there are mercury wetted reeds, it may just be a matter of
Chinglish word meanings.

A mercury wetted contact has less "contact bounce" than a dry contact
and maybe that was what they were alluding to.... maybe they are
really saying the tach is sensitive to bounce on the input?

Getting a hall sensor would be a good idea IMO. They are potted,
sealed and hard to destroy, and have no contact bounce.
 
In article <p18ufl013tt@news7.newsguy.com>, BobEngelhardt@comcast.net
says...
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob
Click to expand...

it means the source for the tach can come from a live pulse source
elsewhere instead if using the a reference sournce from the tach unit to
a isolated switch.

Basically an external source that supplies its own power source to
generate an output reference signal

In the terms of Dry contacts, it means that the contacts can not be
shared with others reference sources on those termination points and
thus the two connections to the contact must be dedicated to the tach
unit. this also applies to sensors dedicated to the tach for use.


In the case of Wet contacts as for this subject, it means the tach can
use an electrical pulse from other sources and most of the time the
input as a wide range scale to allow this.

Picking off an existing inductive sensor that is powered from another
circuit is a good example. just combine the commons .

Jamie
 
Ian Field wrote:
"Bob Engelhardt" <BobEngelhardt@comcast.net> wrote in message
news:p18ufl013tt@news7.newsguy.com...
An eBay listing for a electronic tachometer specifies that it's input can
be a "wet contactor". Is there a standard meaning for "wet contactor"?

In some cases it can mean mercury wetted contacts, but the term "wetted" is
also used to describe when dry contacts carry sufficient current to break
through any oxide or contaminants on the contact surfaces.
Click to expand...

I wonder if Nolox can be used to increase current when applied on top of the oxides its supposed to prevent.
 
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob
Click to expand...

Thanks to my repliers.

I decided that using a reed switch would involve too much fabrication &
fiddling with a mounting. Instead I bought another tach that had a Hall
effect sensor.
 
In article <p1v45201tju@news4.newsguy.com>, BobEngelhardt@comcast.net
says...
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob

Thanks to my repliers.

I decided that using a reed switch would involve too much fabrication &
fiddling with a mounting. Instead I bought another tach that had a Hall
effect sensor.
Click to expand...

wimp!
 
On 2017-12-27, Bob Engelhardt <BobEngelhardt@comcast.net> wrote:
On 12/18/2017 12:42 PM, Bob Engelhardt wrote:
An eBay listing for a electronic tachometer specifies that it's input
can be a "wet contactor". Is there a standard meaning for "wet contactor"?

Thanks,
Bob

Thanks to my repliers.

I decided that using a reed switch would involve too much fabrication &
fiddling with a mounting. Instead I bought another tach that had a Hall
effect sensor.
Click to expand...

hall effect sensor: that would probably work as a "wet contactor", I
guess it's a bit late now though.

--
This email has not been checked by half-arsed antivirus software
 
On 1/1/2018 12:39 AM, Jasen Betts wrote:

hall effect sensor: that would probably work as a "wet contactor", I
guess it's a bit late now though.
Click to expand...

I considered that long enough to find that the prices of the
tach-with-sensor and tach plus sensor were the same.
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top