Murphy Switch

I'm sure a lot of you already know, but in my time, this is the first occasion to come across the term "Murphy Switch". What is this?

When I Googled the term, most references were to the company Murphy Switch or used it in a generic fashion.

... rab

Murphy Switches are extensively used in the petrochemical area. They are know for their accuracy and durability.
Below is a list of their general product line:

- Pressure and Vacuum - Automation Systems, Engine and Motor Controls, and Digital Fault Annunicators
- Temperature - Shutdown Devices
- Fluid Level - Electric Gage and SWICHGAGE
- Time, Vibration and Overspeed - Gen Set Controls
- Magnetic Switches/TATTLETALE - J1939 MurphyLink Instruments
- Engine Panels for Irrigation and Industrial, Mobile, and Marine


FW Murhpy

I've been seeing the term "Murphy Switch" used in a generic manner. I did go to the Murphy Switch website hoping that they would explain the generalized use of their name but uh-uh.

Kinda like using Kleenex to mean tissue paper. Since searching, I've seen it used in this way for tractors, irrigation, marine, etc. but without specificity.

... rab

Ahhh... the Murphy Switch!

On one of my machine consoles there is a pushbutton that was left over from the "old days". It hadn't been used for anything for the last several years. I was often asked, "What is that button for?" To which I replied, "Nuttin' Honey".

About a year ago I put a label on the button indicating that it was a "Computer Glitch" button. When asked, I told them, "If you have a hard time restarting the system for any reason, press this button and try starting again from Step-1".

The older guys loved it! They "knew" that all of their operating grief was from the computers. They hated computers. Most of them are gone now (so too with all of us, sooner or later).

Those that remain have taken to pressing the button as the first step in all start-up/re-start situations as a matter of routine.

The button still does nothing.

I'm going to relabel it as the "Murphy Switch". That has a much better "ring" to it, don't cha think?

Actually the original Murphy switch was just a magnetic relay predominant in the automotive field.

I like Terry's idea better though, its sad tho. I hope these arent the technical/maintenance people.

I have seen the Murphy switch used generrically in two separate fields, both referring to products of the Murphy Switch Company.

In mobile equipment, a murphy switch is usually used for engine protection and consists of a grouped panel with low oil pressure and high oil temperature switches.

In stationary equipment (specifically blowers in wastewater treatment) the Murphy switch is an inexpensive high bearing temperature switch.

Ron said...
"... I hope these arent the technical/maintenance people."

No... they are the production folks.

Somehow, when they press that button first, they tend to follow the proper start-up/re-start sequence.

Regarding "technical people", basically, I is them (him)! Although, I am constantly trying to keep my folks to speed, the problem is trying to keep them up to speed with a dynamic situation - there's always room for improvement and the situation is continuously improving. That means "change", constant "change".

Regarding "maintenance people", they tend to follow the lead from the production folks.

With respect to the "Computer Glitch" button... as some are so fond of saying... "If it Ain't Broke, Don't Fix It!".

It works pretty good... for a "Dunsel"!

That's it. Terry sealed it for me.
My next machine is going to have a whole panel of pushbuttons and pneumatic regulators that dead-end in the panel. THAT should keep everyone busy!!

Keith

Can I get some help please, I cannot find the any key on my keyboard.

Jim

GO JETS

kamenges said:

My next machine is going to have a whole panel of pushbuttons and pneumatic regulators that dead-end in the panel.

Click to expand...

Yes...
Flow controls, pressure regulators, selector switches, pushbuttons, potentiometers.

Gauges that actually move when the "fake" controls are actuated.

Some operators love this kind of stuff. They really think they are in charge...

I dont understand???? Y'all dont program a PUSH THIS BUTTON TO FIX MACHINE into all your applications?

Good point Ron. Most of us have installed 'dummy controls' at one time or another, though not only for 'magic repair'... :nodi:

At my last job, we used to have a big problem with operators cranking up the heat and dwell settings on thermal impulse sealers (similar concept to that L-sealer you rebuilt). They figured out (quickly) that if you increase these settings, the nichrome element burns out rapidly. Of course, once it burns out, they return the setting to normal and call the mechanic, who instructs them to go on break while he replaces the element (again and again).

Once we discovered their secret, we simply moved the adjustment pots inside, but left 'dummy knobs' in the original locations. I don't think they ever figured out why they could no longer choose WHEN to go on break...

beerchug

-Eric

The term "Murphy Switch" is a totally (100%) valid device. I can prove it by comparing it with something we have in the Medical field. Have you ever heard of the term “Placebo”? Believe it or not, it works! Just ask old Mrs. Hypochondriac. When I first heard of the Murphy device, I put it into the same category of a "DEAD-MAN" switch. The first time I heard that one I thought they were just joking! That was until I went on my first EMS run to pick up the remains of someone who was known to take chances.

I originated this thread and yes, this has been a very amusing but not really responsive to the original question (I do, however, thank the first responses from skalt, rsdoran and Tom Jenkins). BTW ... I've spent the last 30 years in machine design and controls and this is the first time that I've come across this reference. I didn't need to know the product line of "Murphy Switch" (that I could find on their website) but how others may use the term.

I am involved in a project where a device was defined as a "Murphy Switch" both in a PLC program and on, what I call, a cartoon schematic. This is a layout where devices are drawn as accurately as they can be portrayed, are shown with lines, representing wires, are illustrated from terminal to terminal. This may appear to be a good way to show device connectivity for someone who doesn't need to understand function but it doesn't work to explain the way the system works (without a lot of research) as would an ANSI style ladder schematic.

It was essential that I understand the function of this particular device (which turned out to be a differential pressure switch, made by "Murphy Switch" no less) to make changes required by my customer.

Usually I find the posts and responses helpful but we certainly went off on a tangent here. I did additional research on this since I wasn't getting a valid response here. The following are my conclusions.

Apparently the term "Murphy Switch" can be used in the following ways:

1) In reference to a device manufacturered by "Murphy Switch" (a real company).

2) A dummy reference. I.e that which is imaginary. Reference most of the responses to the origninal post.

3) Generically. Industry specific reference to a type of switch used in that industry under the impression that their specific use(s) does (do) define the device. Like an oil pressure switch for tractors or a differential pressure switch in drinking water filtration systems (or see skalt reply).

... rab

RAB...

Even if some of the responses were not exactly what you were looking for, in terms of the original posting you made... damned near all of these postings answered the question you asked.

"Be careful what you ask for... you just might get it!"

AND...

"You get what you pay for!"

Besides... we need to untie knots once in a while.