600w dimmable ballast

[LetsGetHigh33]

hi is anyone there able to answer this question please I'm am just wandering if you can dim a 600w bulb down to 250w on a dimmable ballast or if I have to buy a 250w or can I use the 600w bulb and dim that down to 250w?

[Marley]

You can dim the 600w bulb if the ballast is dimmable.

[Mr.furley]

Hey 23, yes you can dim a 600w bulb down to 50%,75% setting on a dimmable ballast. I hear it shortens the bulb life.
Seems safer to use a 600w bulb on a 600w ballast dimming it then using a 250w, get high and accidentally turn up your ballast, don't know what kind of problems it can make and wouldn't want to find out with the cost of bulbs and ballast.
hope this helps

[Marley]

I'm no electrical engineer, but I'm not sure that dimming it will shorten its life. If anything I would think it would extend its life. You're only applying less power to it, which is why it's dimmer. Applying more power than it's rated for would almost certainly shorten its life.

[Potted]

With the ballasts I've had and have all dim able 600 watts I've not come across one that can b set to 250 watts 200,400,600 is all I've ever seen, my 2$

[OzBud]

it can change the light spectrum put out by the bulb as they're designed to work optimally at their rated wattage

[Potted]

I would agree with u on that OZ

[dontknownuttin]

I have a DM myself I run it on the lowest setting 400 watts I then use a 400Watt bulb

[LetsGetHigh33]

Hey Potted here's a 600w ballast with 600wboost, 600w, 400w and 250w setting. Not the one I have.

i have 2 x 600w dimmables with 600+w boost , 600w and 400w settings only.

[Insight]

Something to consider when dimming the lights........

NEMA recommends that high-pressure sodium lamps not be dimmed below 50% of rated lamp power. Dimming below the recommended minimum can significantly degrade lamp life—potentially voiding lamp warranties—while also affecting efficacy, color and lumen maintenance. For retrofit metal halide lamps designed to operate on high-pressure sodium ballasts, and specialty high-pressure sodium lamps (e.g., internal ignitor, etc.), consult the lamp manufacturer about whether dimming is allowed and resulting parameters and limitations.

Besides dimming range, NEMA recommends that high-pressure sodium lamps be operated at full light output for at least 15 minutes before dimming. If a voltage interruption extinguishes the lamp, the timer should be reset only after the lamp has restarted. For more information, consult the Guidelines.

Note that dimming some high-pressure sodium lamps and retrofit metal halide lamps can result in changes to color temperature, color rendering and efficacy. NEMA further points out that high-pressure sodium lamps are susceptible to “drop out”—sudden extinguishment—if rapidly dimmed after the lamp operates for about 15,000 hours. Users may confuse this with the lamp having failed; if the user allows the lamp to cool, the lamp will relight and operate at its rated wattage for its rated life in an undimmed mode. To reduce the potential for this, NEMA recommends slowing the dimming rate to about 1.5 minutes from full output to maximum dimmed condition (while maintaining sufficient voltage to sustain the arc).

https://lightingcontrolsassociation.org/2011/07/18/hid-lamp-dimming/

[Marley]

Interesting stuff. That's why I'm no electrical engineer!