An easy relay question for some of you "more experienced".

[VictorMonopoly]

I have a 3 motion detecter setup that I feel like I've got most everything worked out with. Common, hot and ground are all parallel up to the motion sensors and each has it's own relay after that ties back into common. I'm using three 120V AC DPDT relays (Omron MY2-UA 120VAC), where the coil is rated at 120VAC and the contacts are rated at 5A 240VAC and 5A 28VDC. I'm not using flood lights so the path of travel is from motion sensor to relay to ground. I suppose it's not necessarily travel with AC, but my question is: On a circuit that has a breaker rated for 20A, and no lights to consume energy in the circuit, after the coil is triggered will it continue past 5A and burn up my relays? Insert drawing for the sake of pictures.

 

[davenn]

I have a 3 motion detector setup that I feel like I've got most everything worked out with.

can you please label you diagram and repost it

 

[hevans1944]

The relay coils draw only as much current as is needed to operate the relay at the rated coil voltage. You can connect this to a 200 A circuit breaker and it would not draw any more current than it would if you connected to a 20 A circuit breaker. Circuit breakers are there to protect the connecting wires, not the load. Circuit breakers do not control the current in any way, except to interrupt the circuit when the circuit breaker is tripped or placed in the off position, in which case no current flows no matter what is connected as a load..

 

[VictorMonopoly]

Thanks for the help. I just wasn't sure if putting just the relay in instead of some lights or what ever that the coil wouldn't just fire and then be a complete circuit without any regulation or something. Like putting a paperclip in an outlet. Forgive my ignorance, but it seems these days that Googling something anymore to try to find information, you just sift through more and more and more ads and retail sites instead of finding real information.

 

[hevans1944]

... it seems these days that Googling something anymore to try to find information, you just sift through more and more and more ads and retail sites instead of finding real information.

Back in the day (early 1980s) we hired an expert to construct search parameters and search one or more on-line database that charged by the minute. This was way before the World Wide Web and Google existed, but you can still do that. Someone has to pay for all that data warehousing and the engines needed to search it. Google and their ubiquitous ads are the business model that pays for it now. Even so, Google often returns results that are hidden behind a paywall. Some folks just don't believe information should be freely distributed, especially if they paid to have it published in the first place. Our SQL (Source Query Language) expert was worth every penny we paid them, as were the fees charged by the on-line databases for the time spent accessing their data. Today I can get pretty much the same results for "free" with Google, and if I really need that information I will pay to peek behind the paywall and pass the cost along to the customer.

One thing that is kinda spooky is seeing ads on Google specifically targeted at me. This is mostly a "good thing" to see an ad pop up for, say, an oscilloscope or a soldering station after I have searched for those things, but I wonder how much they know about me that I don't know about me, and how accurate their profile of me really is.

 

[BobK]

One thing that is kinda spooky is seeing ads on Google specifically targeted at me. This is mostly a "good thing" to see an ad pop up for, say, an oscilloscope or a soldering station after I have searched for those things, but I wonder how much they know about me that I don't know about me, and how accurate their profile of me really is.

It is scary how much Google knows about us all. For instance, I have never gotten an ad for one of those devices designed to enlarge a part of male anatomy.

Bob

 

[VictorMonopoly]

So after the motion detectors I can only get the relays to trigger if there's something between the relay and common i.e. a light. And it doesn't just trigger but it buzzes too so I don't keep it on longer than a few seconds so as to not burn it up just in case. I'm stumped as to why they won't just trigger by themselves between the motion sensor and common and when they do trigger I'm curious if the buzzing is from a different Hz issue. Any ideas? Your help is appreciated.

 

[VictorMonopoly]

Okay, so for what I'm doing, the Defiant brand motion sensors with DualBrite won't work. I wasn't able to get to the bottom of why but for the sake of getting this project finished, I don't care. Some different sensors without all the bells and whistles are doing the trick.

 

[hevans1944]

It is good, I suppose, that you managed to "fix" the problem by abandoning the Defiant sensors with their DualBrite dusk-to-dawn accent lighting. Who knows how that would work substituting relays for LEDs? Or did your particular model somehow offer dual light levels (low level if no motion detected, high level if motion detected) using "old school" incandescent-filament flood lamps? And I suppose there was also built-in adjustable timing delays, sensitivity adjustment and such. Way too many bells and whistles if all you need is a cheap motion sensor with an output that can operate a relay.

Last year I purchased this PIR sensor from Radio Shack. It has a very simple interface: +5 V DC power, Ground, and Signal. The signal is a TTL-compatible logic level, so it is very easy to interface one or more of these el-cheapo PIR sensors to, say, an Arduino Uno microprocessor or a Microchip PIC-series microprocessor. The only downside I see to using it in a DIY project is the sensor range, a maximum of about 30 feet and a minimum motion of about 1 m/s. Of course multiple sensors and appropriate programming of the Arduino or PIC could overcome these limitations.

Glad you were able to "fix" the problem without our help. Please visit us again for more "help" if you think you need it.