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Post by Deleted on Oct 21, 2014 10:53:25 GMT
Question for the electrically knowledgeable. On your averaged transformer, the lead that goes to the small round plug has 2 wires. One wire generally has a stripe and the other is plain black. Which one is the positive wire, or is there some way of finding out. I have a tranny with no plug and I'm damned if I know which wire is positive.
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Post by johnno on Oct 21, 2014 12:09:01 GMT
Alan have you got a photo of it? I could never get my head around them to wire them up as some of them have a couple of the wires the same colour on the primary and the same on the secondary side. They don't seem to follow the normal wiring code. ie. striped wire earth, black neg, red pos. on my multi meter if I connect the neg and pos leads the wrong way round to the supply the display would flash with a minus sign letting me know that they are the wrong way round.. sorry i cant be much help
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Post by Deleted on Oct 21, 2014 13:52:32 GMT
Tried the multi meter test john, and I do get a + or - reading depending on which way I have the test leads connected. This tells me that the centre pin is the + side. This works with 12v DC output tranny's. I have a 24V AC output tranny that just shows 24v no matter which way round the test leads are. ?
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Post by Dragon Man on Oct 21, 2014 15:13:12 GMT
I never did work that out Allan Luckily, the Samsung SCB-4000 (SCC-A2333) is reversible polarity so when I made up the plug for mine it didn't matter which way I wired it. But I do know that the SCB-2000 is polarity sensitive. Fortunately when I bought a power supply for my Mallincam it was wired the right way. I don't know about other cameras. There should be a symbol on the power supply saying which is which:
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Post by davy on Oct 21, 2014 17:04:13 GMT
Hi guys. .the cable with the white tracer is the center of the plug and most applications are center positive. To test with a multi meter..put it to continuity and one prob in plug center and ither to bare wire you should get an audio tell tale on the cable wuth the tracer.
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Post by Deleted on Oct 21, 2014 17:22:25 GMT
Tried the multi meter test john, and I do get a + or - reading depending on which way I have the test leads connected. This tells me that the centre pin is the + side. This works with 12v DC output tranny's. I have a 24V AC output tranny that just shows 24v no matter which way round the test leads are. ? In circuits DC red leads are generally positive and black leads are negative but that is not a guarantee. Your multimeter reads + 12V if the red lead is on positive, - 12V if the red lead is on negative. The test leads on my multimeter are jacked. The red lead plugs into a red jack labeled V (Volt) and the Ohm symbol. The black lead plugs into a black jack labeled Com. (Common). If your multimeter leads are jacked and they plug into the meter be sure they are plugged in properly. Your meter will not show + or - when reading AC voltage because there is no + or - in an AC circuit. AC strands for alternating current. Voltage alternates between + and - at a rate of 50 or 60 times per second depending on where you live.
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Post by Deleted on Oct 21, 2014 18:47:38 GMT
Thanks ldb. Yes the multi is working as you described. I never realised there was no positive or negative side with AC. The reason for the question is that I have an AC transformer with no plug on the end and I wasn't sure which wire might be the positive. I connected this 24v tranny to the heater in my cam housing and it is causing a bright white hot spot to appear at the bottom left corner of the image. When I turn off the heater, the white hot spot disappears again. I thought maybe I had wired it wrong.
I will have to investigate the phenomenon further, or install a different heater.
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Post by Deleted on Oct 21, 2014 18:52:25 GMT
Hi guys. .the cable with the white tracer is the center of the plug and most applications are center positive. To test with a multi meter..put it to continuity and one prob in plug center and ither to bare wire you should get an audio tell tale on the cable wuth the tracer. I tried this with 2 different transformers Davy and I got an audio signal no matter whether I touched the positive side or negative side of the plug. I can only assume there is continuity through the transformer itself so this is not a good indication.
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Post by davy on Oct 21, 2014 19:36:03 GMT
Not many thing run 24ac..thats the prob..
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Post by Deleted on Oct 21, 2014 20:12:41 GMT
When I tested the heater in the other housing it did get pretty hot, 60C but did switch itself off when the thermostat reached its set temp. But, I think I may just run the heaters at 12v dc. They will run cooler, but I will feel happier. It only has to keep dew off the optical window after all.
Still at work at 9pm and its crystal clear here. Damned cold but clear. Will fire the cam up when I get home at 10pm and see if I can catch any Orionids.
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Post by davy on Oct 21, 2014 21:25:24 GMT
Was clear for 20 min then clouds rolled in again
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Post by Deleted on Oct 21, 2014 22:19:38 GMT
Crystal clear here. hope it lasts. There are an awful lot of planes about. I think I've caught 2 meteors and some weird UFO's so far.
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