How to check if circuit is powered?

[gary350]

Put an amp clamp on 1 of the pump power wires so you can see it at the house.

Buy a El Cheap O amp clamps. **broken link removed**

 

[Reloadron]

For a totally non intrusive solution:

All in one with the LED already connected. Just run one of the line wires through the doughnut hole. Virtually no soldering or connecting required and no external power required.

Ron

 

[MikeMl]

For a totally non intrusive solution:

View attachment 91116
All in one with the LED already connected. Just run one of the line wires through the doughnut hole. Virtually no soldering or connecting required and no external power required.

Ron

Only $12 at Digikey. You still have to shut power off, get inside the pump controller box, unhook a wire from the contactor, thread it through the hole, and it costs 12/0.25 = 40X what my cell-phone charger did

 

[Reloadron]

Only $12 at Digikey. You still have to shut power off, get inside the pump controller box, unhook a wire from the contactor, thread it through the hole, and it costs 12/0.25 = 40X what my cell-phone charger did

Upon further deep thought and investigation buy a cell phone charger.

But I do love those little things for industrial applications.

Ron

 

[ggv]

You need to be a little more specific about what you are trying to achieve here, ...

Well, I am looking for universal solution if possible to get visual control of all sorts of motors and appliances (garage doors, watering system, etc.) remotely. In this particular case I have a sewage pump that has this float switch, which switches it on and off. However all this equipment is situated around 30 metres away in the backyard and I want to monitor it in the house. Although this float switch seems to be quite reliable, on a couple of occassions something went wrong and the pump kept pumping semi dry. I was lucky to notice it quite soon to stop it, but you can't expect to be lucky for a long time
Therefore I thought I'll get advise in this forum. But it looks like there no simple and cheap solution. I thought there should be schematic in place that starts drawing small current from the mains to lit up an LED as soon as the main appliance starts using current. Maybe using neon indicator is the simplest way to go forward.

 

[Reloadron]

Well, I am looking for universal solution if possible to get visual control of all sorts of motors and appliances (garage doors, watering system, etc.) remotely. In this particular case I have a sewage pump that has this float switch, which switches it on and off. However all this equipment is situated around 30 metres away in the backyard and I want to monitor it in the house. Although this float switch seems to be quite reliable, on a couple of occassions something went wrong and the pump kept pumping semi dry. I was lucky to notice it quite soon to stop it, but you can't expect to be lucky for a long time
Therefore I thought I'll get advise in this forum. But it looks like there no simple and cheap solution. I thought there should be schematic in place that starts drawing small current from the mains to lit up an LED as soon as the main appliance starts using current. Maybe using neon indicator is the simplest way to go forward.

Among the problems you will encounter is the sensors need to be tailored to each appliance application. For example knowing if a current is going to a pump like a sump pump is one thing, it simply tells you that the voltage is applied. If you only look at voltage to a pump, you only know the voltage is present. Knowing current is present tells you the voltage is doing something. However, neither will tell you if a pump is running dry as I mentioned several post ago. You want to know if a pump is moving a liquid like water? Then another type sensor is used. You want to know if a pump is running dry? Then a few sensors are needed, one to tell you the current is drawn and one to tell you there is no flow. See how the list grows?

The best way to look at something like this where several appliances are involved is to sit down with a pencil and paper and define what you want to know, everything you want to know, about each appliance. Once that is known then worry about sensors and exactly what you want to do with the data from each sensor. Also, needing decided is what if any corrective action should be taken for different situations including alarme both audible and call me or text me.

You can have anything you want in a system, just a matter of the cost and building in reliability and quality. That is what it will always come down to.

Just My Take....
Ron

 

[ChrisP58]

If the motor current is different when it's moving water than when it's dry, you may be able to take the rectified output from a current transformer into a window comparator.

Or, if the motor RPM changes between the two conditions, a slotted disk with photo-interupter could be used.

But, if the core problem is to prevent the pump from running dry, then adding a second float switch in series with the first might be the best bet. That way it'll shut down unattended.

 

[RODALCO]

I would use a CT circuit.

Option 1.

I have been using a circuit like that on my 3 kW 13 Amp hot-water cylinder for 25 + years with no problems. I use a utility CT 100/5 Amps, about 6 turns of the 2.5² mains wire around the CT and through the CT centre to get enough flux. At the CT 5 Amp winding a bridge rectifier, 1 Watt series R and a LED. works perfect. As soon the thermostat switches the heater on the LED glows. It also drives an hour meter through a 4N25 Opto.

Option 2.

Is to use a transformer where you can run a few extra turns of correct size mains rated wire around the core. I use this for my TV's. TV gets turned on via remote, The bridge rectifier on the TX 220 V winding charges a small Capacitor to give me some delay and the extra power sockets are switched on, saves having the stereo, PS3, Ninetndo all sitting on standby 24/7 and wasting power. I use a tiny transformer which switches on the power relay to do the switching.

I will do a topic on this with some photo's for this forum.