# Float switch with start stop override



## luminous (Sep 27, 2009)

seems to me all you need to do is add a relay with the float switch on the nc contacts and add the start/stop with the relay on the holding side of the circuit,,it can get more elaborate than that , but that is basics, for safety reasons you want to take the float switch out all together while you are in a manual mode,of course there would be a selector switch added,,,wish i could draw it for you,,i'm sure someone here knows how to post something for you


----------



## luminous (Sep 27, 2009)

I would draw you one up, but I dont even know how folks are putting them smiley faces on here,,sorry x i would put one with a sad expression where the x is.


----------



## stars13bars2 (Jun 1, 2009)

What he needs is a hand-off-auto switch. This allows power to be switched from the on off switch to the float switch, or have both turned off.


----------



## John Valdes (May 17, 2007)

Whats he doing teaching this class. I mean no disrespect, but if he can't draw this simple circuit, why is he teaching a class on electricity.

Same here on posting a drawing. But I can do the smiley faces.


----------



## pudge565 (Dec 8, 2007)

John Valdes said:


> Whats he doing teaching this class. I mean no disrespect, but if he can't draw this simple circuit, why is he teaching a class on electricity.
> 
> Same here on posting a drawing. But I can do the smiley faces.


He never really had to do this situation. It is out of a book that gave him the materials to use but no ladder diagram.


----------



## pudge565 (Dec 8, 2007)

luminous said:


> seems to me all you need to do is add a relay with the float switch on the nc contacts and add the start/stop with the relay on the holding side of the circuit,,it can get more elaborate than that , but that is basics, for safety reasons you want to take the float switch out all together while you are in a manual mode,of course there would be a selector switch added,,,wish i could draw it for you,,i'm sure someone here knows how to post something for you


That is the problem this is on an ancient lab volt trainer. The float switch only has 2 sets of NO contacts.


----------



## luminous (Sep 27, 2009)

ok,I can understand the one set of n o contacts your control voltage runs through them and when the float switch is mechanically activated turning those n o closed completing the circuit, which could be inline of the holding circuit on the starter telling the motor to pump some out,once brought down to the next level using another type of float,or actuater,proximity,etc,that will through the use of external,or internal,(plc) relay,will reset the process,the ladder logic is quite simple, and the most common method of seeing this is with a 3way selector switch,and in most applications there will be another motor/pump waiting on the go ahead to start filling back up,,so there will be safety precautions taken through the field wiring,as well as the plc program,like using the auxillarys on the starters,is this a plc class your in?


----------



## mattsilkwood (Sep 21, 2008)

What is the list of materials that you can use?


----------



## lectricboy (Mar 11, 2009)

pudge565 said:


> My shop teacher would like to find a ladder diagram for a float switch with a start stop button override. He is not able to draw a diagram that would work. Please help with this.
> 
> Edit: To make it more clear he wants it to be that the float switch does not have to be closed for you to turn the motor on with the start stop switch.


 







http://s707.photobucket.com/albums/...tobucket.com/albums/ww76/lectricboy/Float.jpg

I think this what you need.


----------



## Toronto Sparky (Apr 12, 2009)

pudge565 said:


> My shop teacher would like to find a ladder diagram for a float switch with a start stop button override. He is not able to draw a diagram that would work. Please help with this.
> 
> Edit: To make it more clear he wants it to be that the float switch does not have to be closed for you to turn the motor on with the start stop switch.


A push-pull start switch or better yet a hand-off-auto selector switch.
A regular stop start switch would require a magnetic contractor assuming the motor isn't already controlled by one.


----------



## pudge565 (Dec 8, 2007)

My teacher and I think that we have it figured out at this point. I will post a link to the diagram I made when I am at a different computer. My computer is a POS.


----------



## lectricboy (Mar 11, 2009)

pudge565 said:


> My shop teacher would like to find a ladder diagram for a float switch with a start stop button override. He is not able to draw a diagram that would work. Please help with this.
> 
> Edit: To make it more clear he wants it to be that the float switch does not have to be closed for you to turn the motor on with the start stop switch.


I hope this link works. I messed it up the other day.

<a href="http://s707.photobucket.com/albums/ww76/lectricboy/?action=view&current=Float-1.jpg" target="_blank"><img src="http://i707.photobucket.com/albums/ww76/lectricboy/Float-1.jpg" border="0" alt="Float"></a>


----------



## pudge565 (Dec 8, 2007)

Here is the drawing I made.

View attachment Float Switch.bmp


----------



## PapiMayito (Oct 8, 2009)

yeah


----------



## Ray Cyr (Nov 21, 2007)

I see a couple of problems with this circuit. First, the relay and motor starter are in series, this probably won't work. Second, the pushbutton stop switch and the float switch are in series, if the float switch is closed the motor can be stopped using the stop pushbutton but only as long as the button is pushed.


----------



## pudge565 (Dec 8, 2007)

Ray Cyr said:


> I see a couple of problems with this circuit. First, the relay and motor starter are in series, this probably won't work. Second, the pushbutton stop switch and the float switch are in series, if the float switch is closed the motor can be stopped using the stop pushbutton but only as long as the button is pushed.


We don't want to be able to shut the motor off if the float switch is closed. It was the way I worded it. As to the diagram I will redraw it to fix the control relay.


----------



## Ray Cyr (Nov 21, 2007)

Another small note, I don't know what you have for components but it is likely that the motor starter will have a set of normally open contacts that you can use to latch the circuit closed around the normally open start pushbutton. This would eliminate the use of the control relay.


----------



## John Valdes (May 17, 2007)

This is how I would have drawn this circuit. I did not draw the OLR. I usually put it between the starter coil and the neutral. Yes, the neutral.


----------



## pudge565 (Dec 8, 2007)

Ok I had misunderstood the instructor. He does want it to over ride the closed float switch. That way if it stuck closed and was pumping dry you could shut it off.


----------



## Ray Cyr (Nov 21, 2007)

In rereading the whole thread, I agree with those who said to use a hand-off-auto switch. The "hand" contacts would go directly to the motor starter and the "auto" contacts would go to the float switch and then to the motor starter.


----------



## mattsilkwood (Sep 21, 2008)

John Valdes said:


> This is how I would have drawn this circuit. I did not draw the OLR. I usually put it between the starter coil and the neutral. Yes, the neutral.


 The only way you can shut that off is with the stop button. It will burn the pump up.


----------



## Ray Cyr (Nov 21, 2007)

John Valdes said:


> This is how I would have drawn this circuit. I did not draw the OLR. I usually put it between the starter coil and the neutral. Yes, the neutral.


This would actually depend upon the voltage rating of the starter coil and the type of system feeding it.


----------



## mattsilkwood (Sep 21, 2008)

This is what i came up with but I would use a HOA.

Of course if you are useing line voltage for your float switch you can remove R1 and put the float in where the NO R1 contacts are.


----------



## pudge565 (Dec 8, 2007)

mattsilkwood said:


> View attachment 1945
> 
> This is what i came up with but I would use a HOA.
> 
> Of course if you are useing line voltage for your float switch you can remove R1 and put the float in where the NO R1 contacts are.


Ok I will see if this is what my instructor is looking for. On a side note when you want perfectly straight lines in paint hold down the shift key while making it and it will be perfectly straight.


----------



## mattsilkwood (Sep 21, 2008)

I didn't label R3 on the first one.
View attachment 1948


----------



## Toronto Sparky (Apr 12, 2009)

delete


----------



## mattsilkwood (Sep 21, 2008)

The first drawing is wrong, I couldnt figure out how to change it on here.


----------



## lectricboy (Mar 11, 2009)

pudge565 said:


> Ok I had misunderstood the instructor. He does want it to over ride the closed float switch. That way if it stuck closed and was pumping dry you could shut it off.


Then an HOA is the way to go.


----------



## John Valdes (May 17, 2007)

What are you guys using for the drawing software? I need something.


----------



## mattsilkwood (Sep 21, 2008)

John Valdes said:


> What are you guys using for the drawing software? I need something.


 Paint.


----------



## lectricboy (Mar 11, 2009)

John Valdes said:


> What are you guys using for the drawing software? I need something.


I use Visio.


----------



## Toronto Sparky (Apr 12, 2009)

Meanwhile the water is running all the way down the street by now.


----------



## mattsilkwood (Sep 21, 2008)

Toronto Sparky said:


> Meanwhile the water is running all the way down the street by now.


 That's what the stop button is for.:laughing:


----------



## pudge565 (Dec 8, 2007)

LOL well he has to ask the student that asked for help on this one where he found the requirements for it because we have not found it in the motor control books we have.


----------

