LED lamp replacement radio interferance

[hadleigh sparks]

hi everyone , we have just started installing led tubes in place of existing florescents into existing fittings, we are altering the wiring removing the choke and control gear as is required leaving 230 volts at each end of the tube.
We have found that the tubes are causing interferance with the radios and also the sky televisions in these shops ,
has anyone come up against this problem before and if so what have you done to resolve it ??
thanks

 

[Marvo]

You need to identify if the noise is radio frequency of if it's being induced into the power system. Only then can you decide on remedial action.

 

[bugsy]

Chinese LED tubes , not a good choice ,

 

[pushrod]

only know a little bit of theory that the starters in fluorescent lamps usually have a radio interference suppression capacitor in them. Is there a manufacturer helpline?

 

[Marvo]

The starters and ballasts and any associated pfc components should have been removed if LED tubes were fitted. You might get lucky with a helpline or maybe just go back to the supplier they were purchased from. If they're crap quality he would be aware of these problems and might know of a quick fix.

 

[hadleigh sparks]

Chinese LED tubes , not a good choice ,

Cheers , however im stuck with them now and before i order any more if i need to change the spec on them it would be well helpfull to know if maybe a double insulated power supply would help ??
thanks for your help though

 

[i=p/u]

whats a snubber, heard someone mention one of these for interferance??? maybe someone wigth expierience can work this one out

 

[hadleigh sparks]

The starters and ballasts and any associated pfc components should have been removed if LED tubes were fitted. You might get lucky with a helpline or maybe just go back to the supplier they were purchased from. If they're crap quality he would be aware of these problems and might know of a quick fix.

Thanks for your help,
Thanks for that all of the ballast and control gear has been removed from all the fittings leaving 230 volts at each as per manufacters guidelines , they have stated that in their opinoin a double insulated power supply will resolve the problem along with better insulation for the power supply.
Just wondered what your thoughts on that would be
thank again

 

[Dunc]

whats a snubber, heard someone mention one of these for interferance??? maybe someone wigth expierience can work this one out

I think you're right about snubbers being used for radio interference. I know they're also used to prevent surges on contactor coils damaging controls. Had to fit one to a contactor controlled by a underfloor heating programmer/thermostat on a 20A UFH circuit. The surge from the coil being energised knackered the original stat.

Anyway, that's a bit off topic but a snubber is just a capacitor and resistor in series across the live and neutral connections. Don't know what size you would need though or if it would work at all for that matter.

Have a word with the supplier though, if it is a common problem they should know all about it and have a solution. If they don't have a solution return the lamps as they are not fit for purpose.

 

[Marvo]

Thanks for your help,
Thanks for that all of the ballast and control gear has been removed from all the fittings leaving 230 volts at each as per manufacters guidelines , they have stated that in their opinoin a double insulated power supply will resolve the problem along with better insulation for the power supply.
Just wondered what your thoughts on that would be
thank again

Double insulation is a technique used in Class 2 appliances to prevent the user getting an electric shock. I don't see what this has to do with noise issues.
When you say 'double insulated' and 'power supply' I'm assuming you're talking about a step-down PSU, (I maybe losing something in translation also) what type of power supply unit are you using? A link would be helpful. Where is the power supply located? You say in the opening post that the tubes require 220 volts across them so I'm a little confused as to why a power supply unit would be necessary. A link to the specs of LED tubes you're using would also be good.
Just a thought on the fly by missing earths can increase the noise by making any built-in shielding/suppression less effective.

 

[hadleigh sparks]

Double insulation is a technique used in Class 2 appliances to prevent the user getting an electric shock. I don't see what this has to do with noise issues.
When you say 'double insulated' and 'power supply' I'm assuming you're talking about a step-down PSU, (I maybe losing something in translation also) what type of power supply unit are you using? A link would be helpful. Where is the power supply located? You say in the opening post that the tubes require 220 volts across them so I'm a little confused as to why a power supply unit would be necessary. A link to the specs of LED tubes you're using would also be good.
Just a thought on the fly by missing earths can increase the noise by making any built-in shielding/suppression less effective.

Thanks Marvo for your help the tubes have a live feed in one end at the pins and a neutral at the other. The power supply should really be called the LED driver and is located within the tube itself.
their is no seperate cps supplied to the lamp but it isnt needed any way as the tubes are to be double insulated.
If i understand you correctly above if the aluminium body of the tubes was connected directly to the fittings cpc this would help in noise reduction ? have i got this right ?

thanks again for you help

 

[Marvo]

Thanks Marvo for your help the tubes have a live feed in one end at the pins and a neutral at the other. The power supply should really be called the LED driver and is located within the tube itself.

If the driver is an integral part of the tube then it doesn't matter if the noise is being generated by the driver or by the lights, there's no options for a remedy, I would just return it for a refund and buy a better quality unit.

If i understand you correctly above if the aluminium body of the tubes was connected directly to the fittings cpc this would help in noise reduction ? have i got this right ?

You can't earth the actual tube end caps unless a terminal is provided for that purpose but I've never come across an arrangement like this. You should however have an earth connected to the body/chassis of the fitting (assuming it's a metal chassis) but that is for safety and won't help with noise reduction if the driver is in the tube.

 

[hadleigh sparks]

If the driver is an integral part of the tube then it doesn't matter if the noise is being generated by the driver or by the lights, there's no options for a remedy, I would just return it for a refund and buy a better quality unit.


You can't earth the actual tube end caps unless a terminal is provided for that purpose but I've never come across an arrangement like this. You should however have an earth connected to the body/chassis of the fitting (assuming it's a metal chassis) but that is for safety and won't help with noise reduction if the driver is in the tube.

thanks Marvo you have pretty much answered my questions . so basically the power supply will need to have some sort of a suppresor fitted to it , and I think if the unit supply is double insulated then the body of the light would not need to be connected directly to the mass of earth, by virtue of its method of protection.

thanks for all your help