Problem with 400W MH

[dropd80s]

I installed six 400W Metal Halide in my shop recently and finally got a meter installed yesterday so I could try them out. I have them wired in two circuits with three fixtures each. The lights on one circuit are just fine. The other three lights seem to have some issues. The first light in the run is close to or at full brightness, but has a pulsation which makes the light pattern on the floor look as though the fixture is moving. Its very annoying. The following two fixtures in this circuit do not seem to be as bright. When standing under these two lights they do not cast a shadow on the floor as defined as the other four lights. All the fixtures are older units I bought off CL and I understand the ballasts or bulbs may have issues. Anyone have any idea what I may have done incorrectly?

 

[Cougar]

Bulbs need replacing.

 

[dropd80s]

In all three, the pulsing one, or the two dim ones?

 

[Charles (in GA)]

Swap the bulbs around, and see if the problem moves.

Charles

 

[knobby]

if the lamps are new let them burn in. new metal halide lamps tend to be prone to color change/shift in the first 100 hours or so after that they stabilize
if the lamps are older I would suspect them or the capacitor

 

[nehog]

In addition to the above, do a quick check at each light and make sure they all have full line voltage. There is the (remote?) possibility that you've a bad connection. I've never seen new bulbs flicker, though they do have a slight color change as they age.

 

[Cougar]

As suggested swap the bulbs around, that's a good idea and easy check.
Could be something else.

We had 36 MH fixtures, just got done replacing them with 6 bulb T8 fixtures.
With our old MH's anytime they acted up a new bulb cured it.
Any other problem they quit working completely.