Trouble with mechanical timer

[eminor]

Hello, I don't know if this is the right section for this kind of question, I have several mechanical timers on which I connect an odyssea t5ho light with electric ballast, the timers do their job, but a problem occurs when the light is supposed to be off, every 10-15 min, there is like a flash of light for half a second, what is it due to, not that it bothers me but I'm afraid that it damages the light, is it the case, thank you?

i tried 3 others timer, same problem

 

[Mr.Shenanagins]

Mechanical’s are a PIA. You should look into the smart plugs that connect to your wifi. You’ll never have a problem again. I will personally vouch for the Kasa smart plug, as well as several others.

 

[erwin123]

If you must use a mechanical timer, I think that the Ikea timers are relatively the best, and they have a no questions asked return policy, so no harm buying and trying and returning if it has the same problem. If its the Ikea timers causing the problem, then I guess move to smart plugs...

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[Wolf6]

Ive had a lot of issues this year using mechanical timers as well so moved on to Philips hue smart plugs and no issues since. Its a bit more of an investment but peace of mind is worth a lot too

 

[sparkyweasel]

A lot of mechanical timers are incompatible with fluorescents, someimes it's mentioned in the small print on the packaging but not always.

 

[ian_m]

Here is the technical reason LED (and olde fluorescent) lights are often slightly incompatible with "olde yet reliable" mechanical time switches. Basically, generally the contacts of the time switch may have some form of contact suppressor to suppress sparking of the switch/relay contacts. The suppressor (shown as capacitor in my diagram) maybe just a capacitor, maybe resistor and capacitor, maybe something else, allows a slight current to pass through even when the switch/relay is open.

This small current passes into the light fixture, the diode bridge rectifies it and slowly it charges up the capacitor on the input to the electronics. Eventually after seconds, minutes even 10-15 minutes, enough voltage accumulates on the capacitor, that the light electronics thinks power has been applied and powers up the LED's/fluorescent tube. The electronics starts, LED's/tube lights, but in reality there is only the charge on the capacitor, which drains in milliseconds to a low voltage and electronics turns off. This is what causes the light flickering.

It is cured/fixed in many ways:

• Using a different make of timer. See my PLC article. PLC have "naked" relays, no suppression components at all.
• Using an electronic timer that doesn't use relays.
• Using a fluorescent ballast made for UK market, that has passed UK CE standards and not from China .
• Putting, for instance, a 0.1uF 400V mains rated (class X rated) capacitor across the mains input of the light, to "conduct" the current. These should be standard on UK/EU certified lights but are "optionally not fitted" on Chinese lights.
• Put a high value resistor across the mains input of the light unit to conduct the current. Neon bulb and/or mains LED's can sometimes do it. Trial and error required.
• Try a "mains suppressor", "interference suppressor" type mains socket before the light to see if the suppression components (that may or may not be present depending if got from Argos or China) stop the flickering.

Yes the flickering will reduce the lifetime of the light unit as it is being powered on/off regularly. How much reduction in life...no idea.

 

[eminor]

thx so much guys, don't know why i get no notifications