Tower lights

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ceb58

ceb58

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Raeford, NC
I need some suggestions about a situation I have with some tower lights. One of our sites is a joint venture with a local electrical cooperative. We supplied a new building with generator and UPS and gave them space in the building for their equipment in turn we use their tower and they maintain the tower lights. Now the problem is the tower lighting system is an old 120v system with only marker lights and 2 strobes. The height of the tower only requires the lights to be on at dark and are controlled by a photo cell. The problem I am having is when the lights strobe I can watch the voltage on the UPS display go from 121v down to 116v per phase. The 116v is when the strobes are fully illuminated and the voltage will rise as the intensity decreases it repeats this 30 times per min. This is causing the UPS to switch back and forth from utility to batteries because the UPS only has a +/- 2v range. It also drives the 40kw generator crazy trying to keep up with the fluctuation. I have tried wiring the light controller in on a UPS circuit to see if the UPS would "filter" the voltage but it made no difference. The controller has no capacitor's just a relay for the solid markers and a flasher for the strobes. The markers are 150w incandescent and the strobes are 300w on a 300 ft. tower. My thoughts would be to install a buck/boost transformer between the panel and controller but not sure if this would decrease or eliminate the fluctuation ???
 
ceb58 said:
I need some suggestions about a situation I have with some tower lights. One of our sites is a joint venture with a local electrical cooperative. We supplied a new building with generator and UPS and gave them space in the building for their equipment in turn we use their tower and they maintain the tower lights. Now the problem is the tower lighting system is an old 120v system with only marker lights and 2 strobes. The height of the tower only requires the lights to be on at dark and are controlled by a photo cell. The problem I am having is when the lights strobe I can watch the voltage on the UPS display go from 121v down to 116v per phase. The 116v is when the strobes are fully illuminated and the voltage will rise as the intensity decreases it repeats this 30 times per min. This is causing the UPS to switch back and forth from utility to batteries because the UPS only has a +/- 2v range. It also drives the 40kw generator crazy trying to keep up with the fluctuation. I have tried wiring the light controller in on a UPS circuit to see if the UPS would "filter" the voltage but it made no difference. The controller has no capacitor's just a relay for the solid markers and a flasher for the strobes. The markers are 150w incandescent and the strobes are 300w on a 300 ft. tower. My thoughts.would be to install a buck/boost transformer between the panel and controller but not sure if this would decrease or eliminate the fluctuation ???
Click to expand...

Try LED http://www.pointlighting.com/pdf/OL215PFB.pdf
Ask for the power loading profile.
 
Seems strange a 600W strobe load would cause that amount of voltage drop on a 40kW system. I'd be looking into cause before trying to rig a fix. Have you measured voltage and "illuminated" current on the strobe circuit? What happens if you defeat the strobe lamps and leave the controller/flasher active? ...
 
Smart $ said:
Seems strange a 600W strobe load would cause that amount of voltage drop on a 40kW system. I'd be looking into cause before trying to rig a fix. Have you measured voltage and "illuminated" current on the strobe circuit? What happens if you defeat the strobe lamps and leave the controller/flasher active? ...
Click to expand...

I thought the generator was going crazy because it was trying to come on every time the voltage dips below a certain level. Couldn't the lower limits be reset on the UPS and the ATS?
 
Thats just a shade over 3% VD, I'd be surprized if thats giving you problems,lets us know what you come up with.

dick
 
Have you tried every combination of lights, strobes, UPS and generator, while monitoring current and voltage at critical points?
Seems like more clues are needed.

My editing time has not run out. There are "bang-bang" control systems and there are much more sophisticated ones, and depending on what you have you may have some difficulty fixing this.
 
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Can you connect the tower lights to the genny but before the UPS?

I've seen dummy loads installed on incandescent flashers to smooth out the load fluctuations of code beacons with two 620W lamps, but nothing like that for strobe flashers.
 
dicklaxt said:
Thats just a shade over 3% VD, I'd be surprized if thats giving you problems,lets us know what you come up with.

dick
Click to expand...

How did you qualify this? I had to assume 4 AWG copper at 30 Amps and got a
limit of 209.92'?

At 20 Amps its 313.53'.

Skull hasn't direct email, I'd be glad to mail you both!

Fine, this is all based on South Wire I-phone app.
 
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dicklaxt said:
Thats just a shade over 3% VD, I'd be surprized if thats giving you problems,lets us know what you come up with.

dick
Click to expand...
I know it a low voltage drop but I can watch the display and follow the lights strobing by the voltage drop. The problem is the UPS is maxed out on upper and lower limits. It's constantly switching from utility to battery has already caused me to lose 6 string of batteries ( 60 12v batteries) due to swelling because of this.
grich said:
Can you connect the tower lights to the Genny but before the UPS?

I've seen dummy loads installed on incandescent flashers to smooth out the load fluctuations of code beacons with two 620W lamps, but nothing like that for strobe flashers.
Click to expand...
Did not state this in OP. The utility power comes into a service disconnect, through the ATS into a main dist. panel. Out of the main panel the maint bypass switch is fed for the UPS which goes into the UPS back out to a UPS panel where the radios are fed from. Now out of the main panel there is a feeder going to the other end of the building to a third panel. This is where they are feeding the tower light controller. So the lighting system is not tied to the UPS. This panel is only backed up by the generator. I will say this controller and lighting system is in the 25-30 year old range and is nothing like the LED systems we have on our new towers.
 
re-reading the OP, I need to ask:

By 'strobe', do you mean a discharge tube/power-supply unit or just an incandescent lamp that's switched on/off by the flasher?

Thinking about discharge strobes-
Strobes are really nasty customers. The recharge is effectively a pulse discharge right across the line. Most PoCo power won't have a problem with this, but just about everything else will. (Large rock concerts with lots of strobes often have a separate generator just for them.) I don't think you'll be able to make either the genny or UPS handle them directly. Have you contacted the manufacturer? (Are they still in business?)

Try contacting the engineering staff at one of the local TV stations. They may have solved the problem already or know someone who has.


In the latter case (a switched incandescent lamp), can you get a bigger UPS or widen the voltage range? What's the on/off time of the lamp.
 
cadpoint said:
How did you qualify this? I had to assume 4 AWG copper at 30 Amps and got a
limit of 209.92'?

At 20 Amps its 313.53'.

Skull hasn't direct email, I'd be glad to mail you both!

Fine, this is all based on South Wire I-phone app.
Click to expand...


No qualifications ,just looking at the numbers 121 down to 116,

dick
 
25 - 30 years ago. We worked with the county Sherrif dept on a tower and communication building with a similar problem. The very first thing we did was insist that the POCO give us a larger transformer and larger overhead wires to our service point. On generator the flasher was bypassed but the company selling the lights indicated the normal fix was a bank of capacitors.
 
zbang said:
...

By 'strobe', do you mean a discharge tube/power-supply unit...
Click to expand...

ptonsparky said:
.... On generator the flasher was bypassed but the company selling the lights indicated the normal fix was a bank of capacitors.
Click to expand...
Possible explanation, but OP says...

ceb58 said:
... The controller has no capacitor's just a relay for the solid markers and a flasher for the strobes. ...
Click to expand...

...seemingly indicating it is not a discharge strobe.
 
ptonsparky said:
Ours did not have capacitors either and they were not strobes. The neighbors complained about the flashing of those, so they were removed. To bright.
Click to expand...

Aren't these lights installed for safetys sake ? To warn aircraft of tall towers ? The neighbors

compliant that the lights are to bright doesn't make sense in my mind. Have they ever heard of

opaque window shades ?
 
John120/240 said:
Have they ever heard of

opaque window shades ?
Click to expand...

You would think that.

But on some jobs we have to use cut off fixtures and / or fixtures with big shields on them just to keep the neighbors happy.


10.jpg
 
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