Philips Selecon PL1 Range

[adam2]

I do not believe that voltage sag during startup is relevant.

 

As has already been said, the mains into the unit is rectified and then smoothed with a large capacitor. A mains voltage of say 250 volts will cause a greater inrush current than a mains voltage of say 200 volts. A supply voltage of 110/120 volts would further reduce the inrush current as the energy needed to "fill" the capacitor is much less.

 

A lower supply voltage will increase the RUNNING current, but NOT the inrush current.

 

As has already been said, the best solution is to spread the lights over more circuits. Or to devise some way of starting them in sequence rather than all together.

 

Other options include fitting an inrush current limiter to the circuit, this however means (minor) alteration to the fixed wiring installation which will probably be looked upon with disfavour by the building owner. Such a device may also give misleading results when the wiring is next tested.

 

Or fit an inrush current limiter to each light, this will void the warranty but might be worth considering if the warranty has expired.

 

Yet another option is to make inrush limiters with a plug and socket to go between the supply and the lantern. Rather expensive/time consuming in view of the numbers needed.

 

Inrush current limiters generally consist of an NTC (negative temperature coefficient) device in series with the supply. They get warm in use, and can fail explosively at end of life or if an external fault occurs. They should therefore be enclosed in earthed metal and connected via porcelain terminal blocks.

 

Sounds simply to use multiple circuits.

 

 

 

[vinntec]

Thanks for the comments everyone. It is not an easy problem to sort out.

 

My electrician is thinking that some sort of sequential switch on unit might be needed which he has used in the past in broadcast applications with lots of CRTs coming on at the same time, but not something we were expecting with LED.

 

The hot power wiring is all new and certified so we are fairly confident this is not to blame (and where the fixtures are physically rigged also varies a lot). It is not totally impossible that there is a rogue fixture(s) out there, as one or two are pre-production as we were very early adopters of this range.

 

On the other hand, if we ever have moving fixtures, then we probably need a robust hot supply able to take knocks so planning an upgrade for this as well having all LED might not be such a bad idea as long as the cost is containable. But as @indyld says, it would be good to know exactly what is causing this before heading down a major rewiring exercise.

 

Oh my head!

[gyro_gearloose]

Might be best to go with an automatic staged power up system. We’ve had an Emo switcher on our amp rack for years for this very reason

[indyld]

On the other hand, if we ever have moving fixtures, then we probably need a robust hot supply able to take knocks so planning an upgrade for this as well having all LED might not be such a bad idea as long as the cost is containable.

 

The, er, good news is that most modern fixtures have similar SMPS and the 'features' that go with them. The upside to the new world is that getting circuits to power stuff around the place is cheaper and more easily maintained than a ton of dimmers! Well, for that part of the system at least.

 

I do not believe that voltage sag during startup is relevant.

 

As has already been said, the mains into the unit is rectified and then smoothed with a large capacitor. A mains voltage of say 250 volts will cause a greater inrush current than a mains voltage of say 200 volts. A supply voltage of 110/120 volts would further reduce the inrush current as the energy needed to "fill" the capacitor is much less.

 

 

Yes, I can see that now having thought about it more. I think I must have woken up on the wrong side of Ohm's Law this morning. :-)

Edited June 26, 2019 by indyld

[J Pearce]

A small din rail box with some delay contactors might be a good solution, if each socket on each circuit waits 1 sec from the previous socket that should easily spread out the surge without causing significant delay to power up.

 

Easy to do if your wiring is in spurs, more complex if the outlets are wired as a ring (it’d have to be a din rail box at each outlet probably).

[timsabre]

You shouldn't need to go to the extent of individually delayed sockets. Splitting them into 4's would probably work fine.

[themadhippy]

could ask your sparky if alternative protective devices are an option,rewirable fuses,bs88's or even type D MCB's

[Tomo]

could ask your sparky if alternative protective devices are an option,rewirable fuses,bs88's or even type D MCB's

Very bad idea, as the slower curves mean large (but not huge) fault currents can flow for much longer, increasing the risk of fire.

The wiring must be designed for the longer & larger fault currents. It is very difficult to justify them.

 

I'd suggest no more than 4 luminaires on a 10A circuit. If 9 isn't tripping every time then you might be ok with 6.

 

Very important lesson:

LED fixtures will hit inrush and RCD leakage current limits long before they get close to the nominal power limit of the supply.

[themadhippy]

The wiring must be designed for the longer & larger fault currents. It is very difficult to justify them.

thats why I said

ask your sparky if alternative protective devices are an option

[gotty]

I know that this is a year-old thread, but I've just come across it and I'm in the middle of trying to resolve the same problem (with LEDJ units), so thought I'd describe my experience so far.

 

In a community hall there are 12 LEDJ units, and turning on gave the same problem most of the time. There's only a single ring available, with a 16A B-curve MCB, and the distributions are split into 4 via an ordinary mains strip (feeding 2, 4 and 6 luminaires plus an active DMX splitter unit).

 

I did toy with the idea of getting the breaker changed to a C-curve, but decided against it on safety grounds -

I could have hit the guy who suggested replacing it with a 32A breaker!

 

I measured overall inrush - steady current was about 4A, but inrush was hitting up to 100A for a couple of few microseconds, dropping to 4A after a couple of ms (obviously depending on where in the mains cycle the power is applied). That's an average of about 8-9A per luminaire, which was confirmed by drilling down to individual units - this level of inrush surprised me, especially as the whole lot had been tested extensively at home, but via a 32A B-curve MCB,

 

As I had designed and prototyped a user-friendly Arduino-based DMX control box, I decided to move the mains to 4x IEC sockets on the box and incorporate inrush limiting of some sort. I first thought about NTC, but these are bulky and get VERY hot unless subsequently bypassed, with the risk of problems if the bypass relay fails. They also don't provide protection if there's a momentary power outage while they're still in circuit.

 

I also looked at zero-crossing solid-state switching, but decided against it.

 

In the end I decided on staggered switch-on using a commercial opto-isolated 4-relay board driven by the Arduino. I ran a few stand-alone tests with the relay unit, and then incorporated it into the control box prototype. However, during testing in situ, two of the 10A relays eventually started sticking (I'm assuming it's contact-welding).

 

So I now have 4x 16A Omron HR relays, each specifically designed to handle 100A inrush. It meant designing relay drivers (as the original board had drivers on it) but the new prototype is finished. I haven't tested it in situ yet due to limited chances to access the hall at present.

 

Mains safety in the control box is obviously paramount, especially as all of this is going to be mounted on a single PCB.

 

PCB design is nearly complete, and I hope to send it for manufacture in the next week or so once the new prototype has been thoroughly tested.

[Don Allen]

Another option is to make a delayed switch on relay using a heady duty relay, such as an Omron, with a DC coil, use a capacitor to delay the coil switch on, use different RC values to stagger switch on times, make as modules with times marked on putside. If you do not have DC control volts, use a suitably rated X2 cap as a compact DC power supply so they can be ac modules.

[dbuckley]

This interests me:

 

I did toy with the idea of getting the breaker changed to a C-curve, but decided against it on safety grounds

 

What "safety grounds" would these be? I'm used to thinking of C curve breakers as normal, certainly that's what's in my house, at the theatre, my place of work, so I'm wondering why you are reticent to change from B's which are sensitive beasts, to the C. This is quite apart from a ring protected by a 16A breaker....

[richardash1981]

This interests me:

 

I did toy with the idea of getting the breaker changed to a C-curve, but decided against it on safety grounds

 

What "safety grounds" would these be? I'm used to thinking of C curve breakers as normal, certainly that's what's in my house, at the theatre, my place of work, so I'm wondering why you are reticent to change from B's which are sensitive beasts, to the C. This is quite apart from a ring protected by a 16A breaker....

 

The usual concern is not designing an installation with C drive breakers (which is fine if done correctly), but ill-informed people swapping B curve for C or D curve in an existing installation. If done without considering the implications this can lead to circuits which do not meet the fault clearance times required, because for the same fault current (loop impedance) the C curve breaker will take longer to trip. Put another way, the length of 2.5mm^2 ring you can hang off a C curve breaker is significantly less than the amount you can hang off a B curve breaker (tables in the wiring regulations for this) with acceptable fault trip times.

If you are going to make such a change, then a loop impedance measurement at the installation origin and the circuit end would be required (along with the design data about the maximum possible loop impedance at the supply origin ...).

[dbuckley]

Put another way, the length of 2.5mm^2 ring you can hang off a C curve breaker is significantly less than the amount you can hang off a B curve breaker (tables in the wiring regulations for this) with acceptable fault trip times.

 

Interesting. We don't have rings in New Zealand, and our regs don't (as far as I can recall, anyway) differentiate by breaker type.

[indyld]

Seems odd that the disconnection times, therefore the curve type, wouldn't have some bearing on any decent wiring guidance.

 

A B16 is more likely to be on a radial or at least a former ring that has been broken for whatever reason. The term ring sometimes gets incorrectly used to mean "a collection of outlets".

 

The default house-basher go-to is a B type here in the UK.