How to flash a commercial stop light?

[transferguy]

Posted By: bnewland

Hi guys,

I have been asked to install a commercial stop light at a neighbors shop. You know, the red/yellow/green ones used for automobile traffic? Anyway, I have never worked with one before. I am trying to figure out how to get the thing wired up, and make it flash. I was thinking of using a new construction box, with 3 switches in it; one for each light.

When switch 1 is on, and 2 is off, and 3 is off, then RED will be on and flashing. (YELLOW and GREEN = off)
When switch 1 is off, and 2 is on, and 3 is off, then YELLOW will be on and flashing. (RED and GREEN = off)
When switch 1 is off, and 2 is off, and 3 is on, then GREEN will be on and flashing. (RED and YELLOW = off)

Yeah, I know it defies light logic 'cause green doesn't flash, at least that I know of. But that is the way he wants it setup. He also wants to be able to have them all on simultaneously flashing; Hence the 3 switches.

Does anyone have a good way to accomplish this? Is this sounding stupid?

Thanks for any help.

BNewland

[transferguy]

Posted By: chrisb

Not knowing anything about stop lights the first thing you need to determine is what voltage the thing operates at. then you can determine what type of control you need. It could be as simple as 120 volts and three switches plus the flashing device.

[transferguy]

Posted By: Mr T

If you have any of the original controls, get rid of them, they have safety interlocks to prevent dangerous light combinations. Normally there is just bulbs and no guts in the lights.

Next, convert it to run on regular 110v bulbs if it does not already (unless you are going to have long wire runs). Converting to run on 12V automotive lights may be a good idea too.

2 optons: Find a single light flasher that can handle the load of all the bulbs together and switch after the flasher. You could use 3 flashers, 1 for each color, but the flashes will not be in sync with each other if more then 1 is on at a time. The advantage is if they do not handle alot of current. Most light flashers will only flash 1 light.

I did find this thread that may have more info. There is mention of using screw in lamp flashers that are cheap and easy to get.

Web Link no longer exists

If light intensity is not a issue you could convert it to run on 12V and use automotive flashers. Parts may be more readily available and the cost may be lower.

[transferguy]

Posted By: chrisb

Most modern stop lights are LED arrays. I have no idea what voltage they operate on or if the voltage adjustment is done in the light or the controller.

[transferguy]

Posted By: Mr T

Most likely it is not an LED light. Most towns are converting their lights over to LED if they havent already. Because of this, may are replacing the whole light and selling the old ones at surplus auctions. A city near here had opening bids at $7 each with probably 100-150 lights available. There are TONS of surplus incadescent stoplights out there right now. From what I have read, the bulb ones run on 240V. The LED ones may run on the same voltage if they didnt replace the controller in the conversion, or if it's a new system they could run on as low as 48VAC. Most stoplight systems are designed and built job by job, so I doubt they are sold off the shelf anywhere. Considering all that, I am guessing this is a second hand light.

Either way, its best to convert them to a normal voltage (120VAC or 12VDC (short wiring runs)) to make it managable. If you use the original bulbs, you may have trouble finding a replacement (may not be typical medium base bulbs) I'm sure they are not sold to the public (due to lack of need) and ive never seen them at Home Depot. I know in really old lights, the green light is actually blue bulb through a green lens. Also, the original bulb/LED is probably going to be overkill for indoor use.

If it is LED the flasher used would need to be compatible. Many flasher (and dimmer) units require a load to operate correctly. This is one reason why CFL and LED bulbs dont always work in dimmers, motion/occupancy or dusk to dawn sensors.

[transferguy]

Posted By: bnewland

The light seems to be 120v, as the bulb bases are normal incandescent bulb size. This unit did not come with a controller.

I decided to go with a 3 switch setup, power at switch, and install 4 outlets at the traffic light. One of the outlets will have the tab broken off to make it independently operate the red and green lights without flashing them. Yeah, I know he wanted this originally, but I got his buyoff to change to only yellow flashing. The third switch will turn on the second outlet, which will get a single flasher plugged in, and the yellow light plugged into that.

This way all switches operate separate light, and yellow can flash. I plan on using two x fifty foot 14/2 runs to get the juice up to the light.

Did I think this all through all right? Any suggestions on this plan?

[transferguy]

Posted By: Mr T

How are you going to independently power 3 bulbs with 2 wire runs?

[transferguy]

Posted By: bnewland

Posted By: Mr T

How are you going to independently power 3 bulbs with 2 wire runs?

1 common, 3 hot? across two 14/2 runs? fifty foot runs? seemed like it would work to me.