Anyone have a suggestion on an affordable meter/recorder. I am trying to test for a circuit being turned off in the middle of the night. I have traced it and can not find the circuit switched. The circuit is for emergency lighting and I am having to replace batteries every month
Why don't you start by just using an indicating cube relay and a NO push button. Wire the PB and contact in parallel between the line and relay coil and return the other end of the coil to neutral. Energize, push the button and leave. If you come back to find a dropped relay, you know you had an interruption.
You could get more info by leaving the push button out and using your contacts to drive a battery powered hour meter and/or cycle counter. A N.C. contact could drive the hour meter to log the cummulative time of power off while the other N.C. (or N.O.) contact could drive the counter. If you don't need time stamping, you're done. Joe
Joe- exalent idea thanks Steve- Federal campus, Cams a BIG NO NO HotLine1- Traced the circuit back to panel I have found no switches and i installed lock on breaker. This place (as most Fed locations) has outside contractors inspected very poorly or never.
Denver, just because it's federal doesn't automatically rule out cameras. I just sort of threw it out there as an idea, but if it's something you want to try, don't just disregard it- it's all a matter of asking the right person. Especially if the area you want to set the camera up at is unclassified! Ask your sponsor, they can talk to the security manager on your behalf. Heck, they might already have the info you need on the security cameras!
Really, if this is a secure area, you'd have to go through the same security procedures with anything capable of data logging. It would be harder to get permission to set it up in a secure area, but since you don't really need the tape, you could view it right there under the supervision of your escort and have the tape destroyed when you've gleaned what you need from it.
Oh, a possibly easier idea- do you have an ammeter with a min/max setting and an AC/DC adapter? You could clamp an emergency cable, set it on min, and see if it reads 0 the next morning. Or if the batteries in your ammeter are dead when you come in, that's probably a good indication, too!
Edit: idea2: splice a wall clock onto one of the emergency light circuits Won't tell you when the outage happened, but will tell you exactly how long it was!
[This message has been edited by SteveFehr (edited 10-21-2006).]
I think that you're on the right track with a recording type of device. Indeed, since the problem may be intermitant -say, only on Saturday morning- you'ld want to record for a greater period than one night.
BUT- since we have no idea what's going on, why don't we start from scratch? Verify the volts into the units. Then, verify the volts arriving at the batteries. It isn't impossible that the units themselves are killing the batteries. Be alert of over-voltage as well as under-voltage. Heat is a real battery killer- and feeding a battery too many volys will kill it quickly.
Indeed, you might place a thermometer in the units. If these are tamper-resistant fixtures, they could very well be too hot. Especially if the night crew covers them up so as to sleep better! I think medical thermometers have a 'stop' that holds the high reading.
Some places have folks with way too much time on their hands. Some bored folks might be cycling the test buttons- either just for fun, or for some light after 'lights out.' Either case, repeated charge cycles probably aren't good for the batteries.
Absent a proper chart recorder, you're left to improvising. I'd wire a small clock, or electromagnet, inside one of the units. These will at least indicate (depending on how wired) if the test button was pressed or the power failed at some point.
I really can't think of an over-voltage indicator, though.