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Power-User

Join Date: Jul 2011
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Water Tank Float Switch

01/25/2017 11:57 AM

I am filling overhead water tank using 1Hp,single phase 230V pump motor manually using starter with circuit shown below.now i want to do the motor its job of starting and stopping on auto using a float level switch with 1x NO (A1/A2) +1xNC (B1/B2) contacst.i also want to retain the manual control for emergencies.i have no other auxiliary contactors or timers.i have tried but not possible without auxiliary contactors.can someone sharp minded help please.

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#1

Re: water tank float switch

01/25/2017 12:31 PM
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Power-User

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#2
In reply to #1

Re: water tank float switch

01/25/2017 12:42 PM

you have used a three way selector switch with "o","H" ,and "C" contacts.right?

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#4
In reply to #2

Re: water tank float switch

01/25/2017 1:17 PM

If you don't have access to a 3 position switch such as shown by SE, you could use 2 ordinary SPST N/O switches. Place one in series with the float to act as manual off, and another across the float to act as manual on.

That would achieve the same result as does SE's circuit but with ( possibly) more readily at hand hardware.

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Guru

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#3

Re: Water Tank Float Switch

01/25/2017 12:58 PM

These are just switches in single phase. You can always opt to have it with no contactors if you want.

You should learn ladder diagram, it's much simpler to analyze that way in your future project.

I observed you have lots of queries these days.

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#5
In reply to #3

Re: Water Tank Float Switch

01/25/2017 1:35 PM

Draw the correct circuit as a ladder diagram, to get him started.

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#6
In reply to #5

Re: Water Tank Float Switch

01/25/2017 2:01 PM

Go do the work for him. That's what he really wants.

HARIS, TRY GOOGLE!

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#13
In reply to #5

Re: Water Tank Float Switch

01/26/2017 3:45 AM

See #1⇑.

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#7

Re: Water Tank Float Switch

01/25/2017 3:09 PM

Before doing anything more, you must understand the nature of the float switch. Does it have an adjustable set point for on and off? By that I mean can you set it up to turn the pump on at 5 ft, off at 8 ft, something like that? If not, for example if it is a simple hanging "bulb" type mercury switch, you have more problems to solve here.

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#8
In reply to #7

Re: Water Tank Float Switch

01/25/2017 5:00 PM

It also matters whether the float switch your have (or purchase) is NO, or NC. Obviously, it will not work if sensing is backward.

You should still use the load contactors, but use the auxilliary contacts to open/close on load using your switch circuits. Make sure all switches and parts are out of water's reach, in enclosure to protect user from hazardous voltage (anything above 50 V).

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#9

Re: Water Tank Float Switch

01/25/2017 11:20 PM

Do they have a McDonald's in Pakistan, or wherever this is?

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Power-User

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#15
In reply to #9

Re: Water Tank Float Switch

01/26/2017 7:52 AM

we have MR.cod .i like their stuff too much

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#16
In reply to #15

Re: Water Tank Float Switch

01/26/2017 8:33 AM

Sounds a bit fishy to me! Mr. Cod in your part of the world? That must be Swindon or Reading. To much hake there.

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#10

Re: Water Tank Float Switch

01/26/2017 12:02 AM

1. Get a SPST switch rated at 15 A / 250 V

2. Get a single gang junction box.

Install switch into junction box.

Get a float level with the connector tether. ( See picture )

Attach wires from the SPST switch to your supply source and from the SPST switch to the float level tether cord connection.

Attach your motor cord to the float level tether connector.

Install float level in reservoir tank.

The SPST can be used as your manual shut off.

Less complicated = less expensive.

The float level in the picture is rated at 115v. 230 volt float level switches are available.

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#11

Re: Water Tank Float Switch

01/26/2017 2:22 AM

This float switch contains a micro switch rated at 240v. and a heavy ball to actuate it. As it is a micro switch it has BOTH NC and NO terminals. Cheap too. http://www.ebay.com.au/itm/250V-2m-Cable-Liquid-Water-Level-Controller-Sensor-Contactor-Float-Switch-New-/350666723897?hash=item51a55d9239:g:DzMAAOSw4GVYM7CD

To adjust level you anchor the cable in the tank at a point where when the float hangs down it switches on, and when it floats up it switches off. I am sure you can work out an override. e.g. unplug to keep off. separate plug/supply to keep on.

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#12

Re: Water Tank Float Switch

01/26/2017 3:00 AM

Whatever next?

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#14

Re: Water Tank Float Switch

01/26/2017 5:29 AM

Sir, this should be very much a piece of cream cake for you given the fact of all your vastness of knowledge from power stations, earthing and switching yards, and all the honourable knowledge imparted by many CR4'ians that you may run your thriving village consulting enterprise, and not provide suitable compensation or thanks to your share holders.

http://www.oswalsjaipur.in/contact-us.html

I am sure Mr. Ravi Jain (Proprietor) may provide the components you require to lift water and possibly advise of a local electrician to assist your endeavor.

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#17

Re: Water Tank Float Switch

01/26/2017 11:27 AM

Whatever you do, make sure you include an overflow spill pipe to a drain in case the switch fails to turn off = pump on and on

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Guru

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#18
In reply to #17

Re: Water Tank Float Switch

01/26/2017 12:07 PM

No need for that. It is gravity fed. It will spill out the top cover and gravity feed back to the ground. It then has a multi function as a shower or garden irrigation system or perhaps as a evaporatation pond to grow rain clouds. One must always utilise the resources to the fullest uses.

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#20
In reply to #17

Re: Water Tank Float Switch

01/26/2017 1:39 PM

Good safety advice! Another trick is to install two switches. One turn the pump on/off, and the other is only ever a kill switch.

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#19

Re: Water Tank Float Switch

01/26/2017 1:15 PM

You may want to check out these tank float switches:

https://www.grainger.com/category/float-switches/pump-controls/pumps/ecatalog/N-cc8

If this application is for the storage of potable water, DO NOT select a switch containing Mercury contacts inside of it,

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#21

Re: Water Tank Float Switch

02/08/2017 11:53 PM

Since you dont have any spare selector switch, there is one thing you can do, is that, during the use of the float switch for the automatic water filling you need to remove out the self latching contact wire from the auxiliary contact of the main contactor. And if you want to use back the manual control you need to fix back the self latching contact wire to the main contactor. With this condition I can draw you the new circuit for the control. But I think you also know how to rewire it already.

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