Hi there!

I've just turned on a new HPS ballast and it's intermittently making a fairly loud buzzing sound (every mmm 30 seconds to a minute or so).

Should I be worried that it's about to explode or something?? The sounds lasts a few seconds, then stops. The light itself looks fine to me...

I have an RCD as well as a contactor, so I'm sure it's fairly safe, but I've never heard a ballast make a noise like that before

Cheers!

Oh, I don't know if it's relevant, but I do have my internet running over the power lines in the house... could that cause this?

turn ya internet off for a bit and see if it stops ie turn ya pc's off and ya router and see if it stops

Naah - it won't be the 'net powerline thing, it'll be the windings in the ballast resonating - it should stop or die down as it's temperature changes - either way, it's not about to blow up.

Yeah, that is a good idea!

Haven't heard another buzz for the last few minutes though...


Ahhh, that would explain why it's stopped

Thanks man!! I wonder why my old ballasts never made a sound like that

Might be a loose connection, open it up and check it out

The ballasts are made with the windings on the transformer inside covered with resin, potting compound, to stop the vibrations, but over time they become loose and resonate with the electricity going through them.

Could be a loose screw allowing a plate or piece of metal to vibrate. Unplug, allow to sit for about 15 minutes (cool down and capacitor discharge). Check for loose fittings and such. Shake gently to see if you can hear anything rattling around.

Ballasts are pretty heavy!, even hulk hogan would struggle to shake gently

Much easier to open her up

No problem.

Are you built like hulk hogan Rando?, can you balance a thou ballast on your little finger

my 600w ballast has done the exact same thing every week or so for cple days at time for 8 months odd now.. was going to ask this myself
mine aint xploded yet
aint been to keen on openin it up as never done it before... and seen as its went this far, if it aint broke dont fix
whats the life span for ballasts?

sribble more likely to be right i wouldnt bother opening it up really. you can if you want to but its quit common for a buzzin noise to happen, it does it on mine for the first hour or so its started, buzzes for 30 secs then goes off for a min then buzzes again. it stops after a while. had another ballast that did this aswell,thought that was a faulty one untill my brand new one started doin it , an it says on the instructions i got for it that sometimes a buzz can happen an not to worry.

Put ya mind at rest.
On my first grow my ballast never made a sound. It got put in storage for a few months in the loft. Dug it out again the other week for my new grow, and it was doing the same as yours, buzzing for about 10=20 seconds for about a minute or 2. It stopped making any noise until after it had warmed up. I reckon so long as you make sure all connections are fitted tight and your ballast is resting on some no inflamable stuff (mines resting on a layer of underlay and 2 tiles) you'll be OK. The thread I posted in is >HERE<.

Burton

Leepy and I play catch with the wee buggers all the time.