i have a problem. im installing an aquarium return pump which is rated at 85w, but i need to install a float switch as a safety measure(incase of blockages etc), but these are not rated high enough, so would need a relay of some description involved somewhere.
i have noy got a clue on electronics so if someone can draw a wiring diagram or suggest the best options, it would be greatly recieved
many thanks

 

Go to a store and tell them to give you a 12V AC coil relay which can handle your pump. You will also need a transformer to step the grid voltage down to 12V AC. Then use the 12V AC and the float switch to control the relay's coil.

 

Ahhh, wait a minute... why don't you tell us more about this pump?

What is it's rated voltage, and is it AC or DC? Since you already gave 85W, we can figure out the current from that.

What is the rating of the float switch, both current and voltage?

 

Ahhh, wait a minute... why don't you tell us more about this pump?

What is it's rated voltage, and is it AC or DC? Since you already gave 85W, we can figure out the current from that.

What is the rating of the float switch, both current and voltage?

I havnt actually bought the float switch yet. I live in England so the mains voltge is 240v. All I've got is the 85w pump. (eheim compact 5000+... Just google it for specs)
The pump will be used in an aquarium sump, but in order to stop it pumping water back into the main display tank(incase the overflow blocks) I will need a float switch installed somewhere.
I know this is probabally very simple to some people but to me, it's rocket science. Lol.

Is this the type of relay I will need or is this way to big for my needs. .... Link below.

http://www.maplin.co.uk/Module.aspx?moduleno=37495

 

What is the operating voltage of the pump?

 

Check this thread out...

http://forum.allaboutcircuits.com/showthread.php?t=24179