3 position selector switches

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codeunderstanding

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With a 3 position selector switch for motor controls the one with the hand off auto and this is the toggle type switch how are the internal switching inside the switch work? There is 3 terminals on the switch but nothing that says common hand or auto. Is one terminal common, one hand, and the other auto?
 
codeunderstanding, I can't remember using a toggle type switch for a HOA,

but it would have to work the same way. Just like you thought the center

terminal is common ( goes to coil ) flip the switch up and it closes ( to a

control power 'hot' ) that would be HAND, flip it down, hand opens and AUTO

closes. The same control power hot goes to some type of n.o. control device

first, when it closes the power is wired back to the AUTO side of your toggle

which is closed and send the power to the coil.
 
codeunderstanding said:
With a 3 position selector switch for motor controls the one with the hand off auto and this is the toggle type switch how are the internal switching inside the switch work? There is 3 terminals on the switch but nothing that says common hand or auto. Is one terminal common, one hand, and the other auto?
Click to expand...

It depends on the style of the switch.

Many commercial grade switches only have three terminals. These switches function identical to a standard 3-way wall switch.

Industrial grade switches are usually made up of two independent sets of contacts, so they do not have a true "common" terminal. The individual contacts (which may be in a single housing) are operated by a cam and plunger arrangement.
 
What this is for is a septic tank holding tank that when the tank is full pumps it out to the drain field. The auto position does not work but the tank alarm does. The hand position works so I would not think it would be the selector switch that went bad. I will have to check to see if the float switch went bad. Does any one know how those sealed float switches work? It looks like a sealed ball hanging from some so cord?
 
codeunderstanding said:
What this is for is a septic tank holding tank that when the tank is full pumps it out to the drain field. The auto position does not work but the tank alarm does. The hand position works so I would not think it would be the selector switch that went bad. I will have to check to see if the float switch went bad. Does any one know how those sealed float switches work? It looks like a sealed ball hanging from some so cord?
Click to expand...

Couple of things, That switch has been on HAND very few times, and been

on AUTO for 100's of starts so the switch maybe bad. Test or jumper out the

AUTO switch, if still not working then check the float. When the float is just

hanging it should be OPEN, and when the water gets high and it 'floats' that

should CLOSE the contacts. Good luck!!!
 
On all of the similiar systems that I've installed, the float for the high level alarm, and the float to start the pump were seperate items inside the sump.
Sounds like the start float is either hung up or defective.

steve
 
Do those float switches for the lift stations turn upside down when the water gets full and then close the contactors. It looks like there is weights up from the floats maybe a foot attached to the cord and when the weight is below the float the contacts close. Does this sound correct.
 
There is a 3 position toggle ,,,left or up closes contact #1,right or down closes contact #2 and center is off with both switches open,when either switch is closed the other switch is open. SPDT (single pole double throw) center off,many different switch arrangements can be had, Allen Bradley or GE Control Digest's will show you all available.

dick
 
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