mgookin
Senior Member
- Location
- Fort Myers, FL
Had a customer call last month on a Friday afternoon with a problem. Fortunately this customer was in the next county.
Here's the call: Got one of your controls from the supply house, removed a hard wired photocell and installed one of your electronic controls and the lights won't go out. It's been installed 45 minutes and still nothing.
Asked him if it's direct to the lights or to a contactor. He said contactor.
Asked what voltage on the coil side. He said 240V.
Asked if it has a neutral or if it's L1 L2. He said L1 L2. I said you're not the first person to call with that concern. I'll be right there. I want to see it. It will take me 45 minutes to get there. He says he gets off in an hour; let's do Monday morning. Says he's going to put the photocell back in for the weekend. See you Monday. Great.
Get there Monday morning and he's got this huge cabinet with a privately owned tranny nearby a POCO tranny. Inside this big old cabinet somebody spray painted everything green. There were panels in there, contactors, surge arrestors, and about 50+ wires, all spray painted green with zip ties bundling them all. No way to trace anything.
I look at his coil, measure voltage here and there, install our control (new one off my truck), wait the 38 seconds it should take, hear a click and a buzz but no clunk. Lights stay on.
Scratch head, repeat, repeat.
Finally determine that since photocells have no polarity and electronic controls do, they must have L1 and L2 mismatched either at the control connections or at the contactor coil. Determine it's going to be easier to change the connections at the control, so we swap L1 for L2. Power it back up and 38 seconds later and a click and a clunk and the lights go out. Bingo. We then rode around to other cabinets in the area and did more installations to make sure he was in good shape.
While I figured this out in my head and corrected the problem, now I'm trying to say it on paper so I started with a cad drawing which I'd like some opinions on.
Here's my theory.
Please draw your attention to the blue "Look Here L1".
Since it's a NC relay on both the contactor and the control, when first installed both contacts are closed and the lights are on whether that blue "Look Here" is L1 or L2. When the logic tells the control relay to open, it does, but if you have L2 connected at the blue "Look Here" it's not going to open that contactor coil because the potential will be 0V at the contactor coil.
This tells me that 240V hard wired photocells are being made and sold without regard to whether black or white is powering the red. Since it worked with his hard wired photocell, that could only have been powering red from white. His 240V hard wired photocell had the same black, red, white wires all light controls have.
Am I right or wrong?
Here's the call: Got one of your controls from the supply house, removed a hard wired photocell and installed one of your electronic controls and the lights won't go out. It's been installed 45 minutes and still nothing.
Asked him if it's direct to the lights or to a contactor. He said contactor.
Asked what voltage on the coil side. He said 240V.
Asked if it has a neutral or if it's L1 L2. He said L1 L2. I said you're not the first person to call with that concern. I'll be right there. I want to see it. It will take me 45 minutes to get there. He says he gets off in an hour; let's do Monday morning. Says he's going to put the photocell back in for the weekend. See you Monday. Great.
Get there Monday morning and he's got this huge cabinet with a privately owned tranny nearby a POCO tranny. Inside this big old cabinet somebody spray painted everything green. There were panels in there, contactors, surge arrestors, and about 50+ wires, all spray painted green with zip ties bundling them all. No way to trace anything.
I look at his coil, measure voltage here and there, install our control (new one off my truck), wait the 38 seconds it should take, hear a click and a buzz but no clunk. Lights stay on.
Scratch head, repeat, repeat.
Finally determine that since photocells have no polarity and electronic controls do, they must have L1 and L2 mismatched either at the control connections or at the contactor coil. Determine it's going to be easier to change the connections at the control, so we swap L1 for L2. Power it back up and 38 seconds later and a click and a clunk and the lights go out. Bingo. We then rode around to other cabinets in the area and did more installations to make sure he was in good shape.
While I figured this out in my head and corrected the problem, now I'm trying to say it on paper so I started with a cad drawing which I'd like some opinions on.
Here's my theory.
Please draw your attention to the blue "Look Here L1".
Since it's a NC relay on both the contactor and the control, when first installed both contacts are closed and the lights are on whether that blue "Look Here" is L1 or L2. When the logic tells the control relay to open, it does, but if you have L2 connected at the blue "Look Here" it's not going to open that contactor coil because the potential will be 0V at the contactor coil.
This tells me that 240V hard wired photocells are being made and sold without regard to whether black or white is powering the red. Since it worked with his hard wired photocell, that could only have been powering red from white. His 240V hard wired photocell had the same black, red, white wires all light controls have.
Am I right or wrong?
