LED Floodlight with Time Lag Switch - LED Keeps Flashing

[danieloverton1984]

Hi,

I've read these forums quite a bit as a guest and got the help I needed. I'm hoping someone will be able to help me with my own question now.

On the exterior of my house I have 3 PIR Security lights and have recently added a 10w LED light attached to a time lag switch that will illuminate the dog pen for our guide dogs.

The LED light, when attached to the supply works fine. I have wired it correctly to the time lag switch and when the switch is activated the light remains on for the appropriate length of time. However, the LED light flashes when the switch isn't activated - the neon indicator on the switch also flashes in time with the LED light.

Video of the light flashing:

http://youtu.be/sptQ1HCzfAA

Instructions for the time lag switch:
http://www.cpelectronics.co.uk/phpincs/deliver_pdf.php?type=extras&id=51

LED Floodlight Website:
http://www.gwsled.com/productshow.aspx?id=81

The time lag switch instructions recommend using 1uf of power factor correction for each item being switched. I have emailed the company and they have recommended using 4uf of power correction factor capacitor. The switch company recommended this http://uk.rs-online.com/web/p/polypropylene-film-capacitors/4515354/ for installation in the light fitting across the switched live and neutral connections.

I have a couple of problems though:
1) Space in the back of the LED is very limited, would it be ok to install the capacitor between the switch live and neutral in the junction box (pictured)?
2) If I can install it in the junction box, does anyone know a) which size should I buy and b) where can I get one with leads rather than push connectors?
3) Would I have this problem with a 120w Halogen floodlight?

I've looked at a few posts about this issue with LEDs, one of which recommended 0.1uf capacitor and 100 ohmn resistor which lead me to purchase http://www.maplin.co.uk/contact-suppressor-498 - which didnt solve the problem and I realise why - LoL.

If I'm honest, I'm beginning to wish I had just bought a £5 halogen 120w floodlight. The LED one cost me £10 and I like the colour and crispness of the light, but buying these additional capacitors is just adding to the cost.

Thanks for any help you guys can offer.

A few pics to clarify things...

And for anyone wondering why I want the setup I have... The front and back garden are covered by a PIR, the side section of the house has a PIR pointing towards the front garden so that it activates when we approach the side door. Our guide dogs use a pen for their "business" and this pen is in the section that isn't covered by the PIR lighting - plus, when they go for their business we are often stood still so the PIR wouldnt see us anyway. I didn't want a normal switch either because nobody seems to be able to turn anything off in this house and the light would probably be on constantly. Hence, a time lag switch that keeps the light on for a programmable amount of time and a nice LED light.

 

[ericmark]

There are two possible causes:-
1) The time lag switch uses a solid state relay which does not switch off completely.
2) The capacitance and inductance of the cable does not match and there is a small amount of energy being transferred.
Either way quick cure is a tungsten lamp in circuit it can be very small like an appliance bulb 5 or 10W is likely ample.

One could as instructions suggest match the cable but either way could be causing the problem and without some form of meter you could be playing for ever.

So I would fit an extra bulb holder with a bulb like this

 

[bernardgreen]

Been asked and answered many times

When the switch is OFF capacitive coupling between Live and Switched Live in the wiring to the switch allows enough energy to reach the lamp and make it flash. A well known problem with energy saving lamps. They save this very small trickle of energy until it is enough to make the lamp flash.

Putting a capacitor across the lamp will absorb this energy and prevent the lamp flashing.

Capacitor 0.047uF micro Farads 250 volts AC in series with a resistor 100 ohms

Which come pre-packaged as a contact suppressor from RS Components

RS Stock No. 206-7847
Manufacturer Evox-Rifa
Manufacturers Part No. PMR209MB5470M100

There are other sources of the contact suppressors
Back to top

Read more: //www.diynot.com/forums/electrics/low-energy-lightbulbs.354983/#2674731#ixzz2b6MVZeeg

 

[danieloverton1984]

Capacitor 0.047uF micro Farads 250 volts AC in series with a resistor 100 ohms

Which come pre-packaged as a contact suppressor from RS Components

I got a contact suppressor from Maplin http://www.maplin.co.uk/contact-suppressor-498 which is 0.1uf with a 100 ohmn resistor in series. It doesnt appear to have changed anything - although its installed in the junction box rather than in the back of the light fitting. Does it need to be in the back of the light fitting?

 

[skotl]

Capacitor 0.047uF micro Farads 250 volts AC in series with a resistor 100 ohms

Which come pre-packaged as a contact suppressor from RS Components

I got a contact suppressor from Maplin http://www.maplin.co.uk/contact-suppressor-498 which is 0.1uf with a 100 ohmn resistor in series. It doesnt appear to have changed anything - although its installed in the junction box rather than in the back of the light fitting. Does it need to be in the back of the light fitting?

Yup - as per the link in Bernard's post. It's to suppress the energy at the bulb.

 

[JohnW2]

I got a contact suppressor from Maplin ... It doesnt appear to have changed anything - although its installed in the junction box rather than in the back of the light fitting. Does it need to be in the back of the light fitting?

Yup - as per the link in Bernard's post. It's to suppress the energy at the bulb.

The pics seem to indicate that the JB is only a few inches from the light fitting. I really don't believe that it would make any difference which of those places the 'suppressor' was installed, do you?

Kind Regards, John
Edit: format corrected

 

[ban-all-sheds]

What have you connected it between?

 

[danieloverton1984]

What have you connected it between?

In the JB there are Wago junction blocks/connectors.

One Wago is... Switched live + Live (to light) + Longest end of the contact suppressor.

Another Wago is... Neutral (from light) + Neutral (back to supply) + Shortest end of the contact suppressor.

Theres the same for earth obviously and the onward connection to the back gardens halogen security light.

So in essence the contact suppressor is wired between the switched live junction and the neutral junction.

 

[JohnW2]

So in essence the contact suppressor is wired between the switched live junction and the neutral junction.

That ought to do it - although you have indicated that it doesn't! Did installing that suppressor change the behaviour at all?

Kind Regards, John

 

[danieloverton1984]

So in essence the contact suppressor is wired between the switched live junction and the neutral junction.

That ought to do it - although you have indicated that it doesn't! Did installing that suppressor change the behaviour at all?

Kind Regards, John

No, it hasnt changed anything. It still blinks at the same rate.

The only thing I have just thought about is that the legs of the suppressor might not be thick enough to "latch" into the Wago connector. But they certainly weren't noticeably loose when I installed it, so its a long shot.

 

[JohnW2]

No, it hasnt changed anything. It still blinks at the same rate.
The only thing I have just thought about is that the legs of the suppressor might not be thick enough to "latch" into the Wago connector. But they certainly weren't noticeably loose when I installed it, so its a long shot.

If they weren't making good connection, that could obviously be an explanation - but if you can't pull the leads of the suppressor out of the Wago, then they should be making good enough contact.

Kind Regards, John

 

[danieloverton1984]

No, it hasnt changed anything. It still blinks at the same rate.
The only thing I have just thought about is that the legs of the suppressor might not be thick enough to "latch" into the Wago connector. But they certainly weren't noticeably loose when I installed it, so its a long shot.

If they weren't making good connection, that could obviously be an explanation - but if you can't pull the leads of the suppressor out of the Wago, then they should be making good enough contact.

Kind Regards, John

They definitely can't be pulled out.

Perhaps it's due to the suppressor being only 0.1uf. Since I can't find another one bigger that's available locally or for less than £5 delivered I think I'm going to pick up a 120w halogen tomorrow and fit it instead.

 

[JohnW2]

They definitely can't be pulled out. Perhaps it's due to the suppressor being only 0.1uf. ...

You say 'only', but that's double the capacitance of the 0.047μF which Bernard suggested - and those are usually adequate for this purpose. Hence, unless you have an exceptionally long cable run, I would have expected 0.1μF to be more than big enough.

Kind REgards, John

 

[bernardgreen]

It might be that the timer when OFF "lets through" a lot more current than is norma for similar timers and controllersl. The fact that the web site mentions a 4 uF power factor correction capacitor is a big hint that the let through current has to be high. The flash rate of what is quite a large LED supports the theory the let through is high.

The is a let through current as there has to be some current through the timer when OFF in order to power the timer's electronics.

If capacitors cannot solve the problem and the timer is not defective then it maybe necessary to use relay to provide a clean break switch for the LED but the relay coil may not allow the necessary let through to power the timer.

 

[RF Lighting]

Connect a neon indicator between switched live and neutral in the jointbox just below the floodlight. Works a treat.