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Hi,
I need to switch on and off a 120v AC Pump with a float switch, while keeping the switch on a seperate no voltage circuit. Im not sure what I need to accomplish this.
Thanks!
You can't do it with "No Voltage" however it is easily done with Low Voltage and a relay. You have a float switch and it will need to send some sort of voltage to a relay and the relay in turn takes care of the pump.
Ron
The problem is that the float switch will not handel the current of the Pump so I can't connect it direct I need the Relay in between.
I Guess what i need is a relay with a coil that will switch at say 9V or 12V and handel the 120V current on the other end?
That relay coil takes a relatively high voltage (but low current) to switch it on. The coil is is designed to operate from 120V AC power, providing the exact opposite of what you want, because there will be 120VAC across the float switch contacts when they are open.
I'm guessing that your requirements are "isolation from the AC power line", and "minimize shock hazard" by using transformer isolation from the AC power line, and using low-voltage DC on the switching side of the relay?
A battery circuit is NOT the way to go, because if this is for a "standby" application, the battery is guaranteed to be dead when needed...
Home furnaces and air-conditioning units are full of "low-voltage" transformers, relays, thermostats, etc. For example, the 120V to 24Vac transformer in your furnace sends a current through your wall-mounted thermostat. When the thermostat calls for heat, it closes its contacts, pulling in a relay with a 24Vac coil inside the furnace which powers (amongst other things) the 120V 1/4HP blower motor.
I cite this because this is the method I would use for your application. A 24Vac industrial "control" transformer, a 24Vac relay with contacts suitable for switching your pump are readily available at industrial electric distributors...
Can this be done with say a 9V DC Battery on the switch side? and if so what type of Relay would need to be used? I would assume the DC Voltage would not be enough to switch something like G2R-1A-T-AC120.
Thanks