Re: streetlights cycling -- layman's inquiry

On 3 Dec 2003 02:35:33 -0800, [EMAIL PROTECTED] (Tom Beckett) wrote:

[snip]



>When you say "If one luminaire on a circuit starts the others soon
>> follow." do you mean start each evening - which is normal - or start
>> to cycle - which is not normal?
>
>No. They soon begin to cycle.

I do not see any way that lamp operating on their own ballasts could
interact to cause cycling unless the line voltage is changing or, as
Terry has asked, the ballasts are connected in series. (I know that
some old street lighting systems using incandescent lamps were often
connected in series. I was unaware that this was ever done with
ballasts for discharge lamps, but Terry has a lot more experience in
this area than I do.) 

>> What are the luminaires like? Do they use a reflector? If so, are the
>> luminaires designed for HPS lamps?
> 
>No reflector.  They have a glass globe surround of about 24 " dia.They
>hang over the sidewalk not the street per se. They sprout from the
>same post as the luminaire for the street.  Those luminaires work fine
>until all the globes on the circuit start to cycle.  These globed
>luminaires seem to drag the whole circuit down, if that's possible (
>no idea ).

This should rule out the problem of light being reflected back through
the HPS arc tube - which can cause such problems. 

>As far as question of whether the proper bulb is being used -it might
>not be.  No one seems to have the definitive answer to that.
>
>> Which HPS lamp is being used?
>
>I'll have to get back with a model number.

Well, if you are going to follow up on this you need both the model
number or ANSI designator of the ballast plus the model number or
wattage of the lamp. That is the only way to be sue the lamp and
ballast match.

>> Has anyone measured the line voltage?
>
>Lighting contrator says it is within accepted parameters.

Not a very good answer. It would be more useful to have some idea
about the actual line voltage

>The City's own electricity utility has said there is nothing amiss
>with the line
>But in the past they have missed bad lines elsewhere in the city by
>not thoroughly checking them with the oscilloscope.
>
>
>Sorry.  I realize now there needs to be much more info to get a handle
>on even possible causes. Thank you.

Well, lamp and ballast model number seem to be the first place to
start. Plus the question of series-connected luminaires.

See Terry's excellent post for more information. 

-- 
Vic Roberts
http://www.RobertsResearchInc.com