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#1
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
Hi:
Looking for a simple circuit idea that will tell us when a 12V DC load is activated. This is a critical load so we don't want to do anything that will make it unreliable. The circuit just has to activate a tiny relay when the load is going. Any ideas? Thanks |
#2
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
What kind of load? How is it activated?
Simply, an opamp connected across a current sensing shunt in a voltage comparator configuration will work. Putting the relay coil in line with the sensed loads feed 'might' also work, depends on the loads etc. Ian |
#3
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
On Sat, 4 Mar 2006 23:35:48 -0500, "jon doe" wrote:
Hi: Looking for a simple circuit idea that will tell us when a 12V DC load is activated. This is a critical load so we don't want to do anything that will make it unreliable. The circuit just has to activate a tiny relay when the load is going. Any ideas? Thanks Take a reed relay element and take a number of turns of your load wire around it! If the required switched load is too great for the reed then slave it through a larger relay! Cannot get much simpler than that! Richard Nb "Pound Eater" Parkend G+S Please remove your hat when replying |
#4
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
What are you willing to define as "evidence" that the load is activited?
A specific level of current drawn by the load? Presence of 12 VDC at the load? Switch to the load in the "on" position? Presence of the load's output (e.g., sound, heat, light, motion, water flow, etc.)? The load's output is usually, but not always, present when the load is drawing current of course. An electronic navigation device could draw current forever and yet not work at all. The most obvious solution (power the relay with the same switch you use for the load) is probably the most reliable method if all you want to do is verify that power to the load is switched on. Other seem to have figured out what you are seeking from your post, but I can't see the info there. Chuck Electricky Dicky wrote: On Sat, 4 Mar 2006 23:35:48 -0500, "jon doe" wrote: Hi: Looking for a simple circuit idea that will tell us when a 12V DC load is activated. This is a critical load so we don't want to do anything that will make it unreliable. The circuit just has to activate a tiny relay when the load is going. Any ideas? Thanks Take a reed relay element and take a number of turns of your load wire around it! If the required switched load is too great for the reed then slave it through a larger relay! Cannot get much simpler than that! Richard Nb "Pound Eater" Parkend G+S Please remove your hat when replying |
#5
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
Hi:
Thanks for the responses. The load is a very quiet water pump. It draws between 5 and 40 amps depending on water load. We need to know not just when the on/off breaker is activated, but when the pump is actually on and drawing battery load. The circuit will drive an indicator lamp via a relay. I have some small reed relays, do you think a coil of the pump's feed wire will trip it to make contact? That would be easy. Thanks "jon doe" wrote in message ... Hi: Looking for a simple circuit idea that will tell us when a 12V DC load is activated. This is a critical load so we don't want to do anything that will make it unreliable. The circuit just has to activate a tiny relay when the load is going. Any ideas? Thanks |
#6
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
On Sun, 5 Mar 2006 14:07:57 -0500, "jon doe" wrote:
Hi: Thanks for the responses. The load is a very quiet water pump. It draws between 5 and 40 amps depending on water load. We need to know not just when the on/off breaker is activated, but when the pump is actually on and drawing battery load. The circuit will drive an indicator lamp via a relay. I have some small reed relays, do you think a coil of the pump's feed wire will trip it to make contact? That would be easy. Thanks "jon doe" wrote in message Just look at the specs on reed relay elements. if trigger level is 100 Ampere turns then 20 turns around element will give you what you want. Simple option for encapsulated relays is to break open case and cut off existing fine wire coil. You now have a former to wind your heavy gauge wire.. Otherwise wind your wire around a screwdriver of similar diameter to the element then slide element in. I suggest that you do not wind directly on element - they are fragile! I have done just what you are requiring with a water pump. the reed switches on a battery clock. Runtime of clock tells me the state of my water tank. Its a very cheap but working option. Richard Nb "Pound Eater" Parkend G+S Please remove your hat when replying |
#7
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
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#8
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
Yes, I know the other suggestions above are actually home-made
ammeters. Don't blast me. I know there are small aircraft ammeters with built in alarms, which you might find beneficial... not sure what marine offering exist. |
#9
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
On 6 Mar 2006 07:22:48 -0800, "
wrote: How about using an AMMETER ? http://en.wikipedia.org/wiki/Ammeter For a simple indicator, they take up too much panel space. |
#10
posted to rec.boats.electronics
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Load In Use Indicator Circuit Needed
"Wayne.B" wrote in message ... On 6 Mar 2006 07:22:48 -0800, " wrote: How about using an AMMETER ? http://en.wikipedia.org/wiki/Ammeter For a simple indicator, they take up too much panel space. put a light bulb, of low wattage and appropriate voltage across the contacts. Bulb lights when pump is off. Or put a relay coil (NC) in place of the bulb and use to light bulb when contacts close. A small current would flow through the pump all the time but it shouldn't do anything. |
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