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HID's raising cain with my timers

Seems I can get a timer to hang together for more than ten cycles when firing up my MH's. Should I be using a relay of some sort? Any ideas?

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Permalink Reply by Vlad Jovanovic on September 26, 2014 at 9:05am

Exactly what equipment are you using (ballast, bulb, Wattages, what type of timer etc)...

I have a wide range of ballasts (from the old style magnetic types, to digital dimmable, e-ballasts) running a variety of bulbs (MH, MPS, Ceramalux, Pulse Start bulbs (those are pretty neat, they don't have a starting probe electrode in the arc tube, but use this weird high voltage ignitor instead)...in a range of Wattages (mostly 600's 1,000 and 400Watt) and all these lights are turned on and off using cheapo-mechanical timers (yet ones that can take the initial load when the ballast kicks on). I have a pair of crappy Chinese made mechanical timers that have been running 400Watt MH's in my greenhouse for few years now without fail. (Barring the occasional propensity for the dial on one of them to get stuck. This is remedied by turning the dial manually to get it un-stuck...after which the same timer runs without fail again)...

Many common electrical devices will draw much higher amperage at initial draw, than what their rated running amperage is (this high initial draw and the subsequent heat is why pumps tend to fail quicker if they are turned on and off repeatedly...though magnetic drive pumps seem to be a good design around that problem) This high initial draw often lasts just a fraction of a second as the device is starting up, maybe your particular timer can't handle it? IDK...more information about your specific equipment would to help to possibly get to the bottom of your timer issue...

Permalink Reply by Ian Cameron on September 27, 2014 at 3:31pm

Vlad, am using old style magnetic ballasts, 250watt MH bulbs and a Woods outdoor rated timer,

Specs on the timer are: 125v, 60Hz, 15A 1875W resistive, 15A 1875W tungsten, 8A ballast, 3/4 HP, 15 FLA, 90 LRA. As you can see from the specs, they should be able to handle the start up needs.

I used these timers for 3 yrs on my 250W T5's with no problem. 1 timer per lamp.

Just when I switched to the HID's to check everything out, things started to happen. Could be that they are getting worn down and need to be replaced. That's why I wondered if a relay setup might be more beneficial in the long run.