I have an old ballast fluorescent (3 foot tube), and when it's on (even with the tube removed), the circuit breaker in the fusebox (MCB) buzzes loudly. I've put my lighting onto the computer's UPS, and now that buzzes too. How can a ballast cause this?
Why do people point to their wrist when asking for the time, but don't point to their crotch when asking where the bathroom is?
Because when you have a bath the water covers your whole body.
Bill
Well, I cannot be sure, but do these devices effectively load one half cycle of the mains more than the other. I remember we used to have an old telly with a half wave rectifier in it, and if you plugged that in to one of those lawn mower protection things, it used to buzz as well. Brian
"The bathroom" is a snobby way of saying "the toilet".
But it's a pretty small load compared with the entire circuit (which is mainly CFLs with some LEDs). The CFLs and LEDs don't cause the buzz. Even if they did, they aren't all in the same way round as BC caps aren't polarized.
Although I suspect you may be correct, as the hum sounds like 50Hz, not 100Hz, which suggests half wave rectification.
Round here 'the bathroom' means 'the place where we keep the coal' and 'the toilet' is a snobby way of saying 'the shithouse'. I know this because my wife has a friend whose husband has an indoor job and she says 'toilet'.
Bill
Dust tha' work down mine? Is tha friend workin in mill? Careful, there's trooble at mill.
Work down t'pit? Tha must be jokin lad. Pit's shut. Now we all guz down t call centre and works theer. It's much cleaner, but there no cameraderie. No esprit de corps. Tha knows what I mean?
Bill
I resigned from a call centre, they treat you like shit.
failing insulation? There should be no current flow with no tube in.
NT
Does it not still act as an inductor across the mains? The fitting has only been used for one tube, so it's not old.
The inductor is in series with the tube, not across the mains. What will be across the mains in this case for a larger than 20 watt fluorescent fitting will be a PF correction capacitor. Maybe, just maybe, this is what's causing the buzz in the CB.
en with the tube removed), the circuit breaker in the fusebox (MCB) buzzes loudly. I've put my lighting onto the computer's UPS, and now that buzzes too. How can a ballast cause this?
only been used for one tube, so it's not old.
But how?
NT
And why would it do it but no other capacitor does? Ok, I've not got CBs on the other circuits, but plenty people do. Those capacitors are on hoovers, PCs, etc, etc.
And why would it do it but no other capacitor does? Ok, I've not got CBs on the other circuits, but plenty people do. Those capacitors are on hoovers, PCs, etc, etc.
This is the culprit in the light fitting:
There used to be the type that didn't have a starter switch, but had a transformer across the tube to drive the heaters. When the tube struck, the series choke on the same core limited the current in the tube and stopped the current in the heaters.
That's the classic "Quickstart" circuit. It was very effective in making the fitting 'instant start' (200 to 300 ms turn on delay with no flicker). It also extended the tube life considerably over the cheaper switch start circuit in frequently switched usage cases.
I must point out that after the tube struck, the transformer kept supplying heater current at a reduced level, it didn't cut out. This actually extends the life by reducing the risk of cathode stripping by ionic bombardment in the absence of sufficient electron emission due to underheating.
Effectively, it gave you a starting experience more akin to a normal incandescent lamp than to the more common switch start fluorescent fittings. Effectively, it allowed you to walk straight into a fully lit kitchen immediately after hitting the light switch (no disco strobe effects for the first second or so, typical of the cheaper fitting).
The 'Quickstart' transformer wasn't always integrated with the series choke (i.e. a high leakage transformer). You could simply wire it across the tube in an existing switch start fitting, assuming there was room for the transformer, and remove the starter switch, leaving the series ballast choke in circuit. In fact, all of the rescued from the works skip 4 foot Quickstart fittings I acquired used seperate choke and transformer components.
I only used one of those fitting in its unmodified form for the basement lighting. The existing kitchen 'slimiline' fitting was just too 'slimline' to accept the quickstart transformer 'as was' without my stripping the 'mounting can' away to allow me to squeeze the naked transformer into said slimline fitting where it gave me 25 years or more of instant fluorescent lighting.
After having the ceiling repaired after a serious roof leak, the XYL insisted on it being replaced with an even slimmer fitting earlier this year. I made sure to specify one with an electronic ballast so as to continue the 'Instant Start Tradition' we had enjoyed from the half century old technology of the "Quickstart" circuit (plus, I wanted the extra 10% boost in efficiency that HF ac operation endows on fluorescent tube operation compared to 50/60Hz ac operating frequency.
Between the HF frequency boost and the use of a modern slimline 4 foot tube rated at 36 watt over the original 40 watt tube. I saw a power saving of 16 watts (52 - 36 watts - total consumption of lamp plus ballast losses, old - new).
Without some other compelling reason (in this case the XYL's insistence on a change of fitting), I'd have cheerfully kept the old Quickstart employed in spite of the extra 16 watts consumption - ROI period to cover the cost of such an 'upgrade' would be about a decade. A period long enough to question whether the electronic ballast would last long enough for me to realise the energy saving benefit.
What I do notice is that, whilst the startup time is around the same
2 or 3 hundred ms, it exhibits a 50Hz flicker, unlike the half century old technology which simply showed a flicker free ramp up.The other thing, which I suspect is a slimline tube characteristic, is a further 10 second or so ramp up to full brightness, not a huge change in output level, just enough to be observable (probably a ramp up starting from 75% before reaching 100% output). I dare say a similar effect occurred with the older fatter tubes but most likely a changethat went from 90% to 100%.
Maybe it's just the modern RCB's reacting to such a high capacitance producing 250mA current, even though it's 90 deg out of phase with the voltage.
If that was to correct the phase, then when the tube was lit, why was the buzzing still occurring?
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