70w metal hallide floodlight

[Welshsparky86]

hi everyone!right, got a problem!got called to a milking farm this morning due to 2 metal hallide floodlights not working.there are a number of sheds but this one is the furthest from the consumers unit and is fed by a 2.5mm submain for the floodlights and a twin 4ft fluorescent. problem is when the pump for the parlour kicks in it interrupts the floodlights and so they switch off. they were fine last winter but not this one. the voltage drops down to 231v from 239v when the the pump kicks in. im thinking maybe a voltage regulator on the circuit which would stabalise the voltage so it doesnt interrupt the floodlights. opinions?and how much would one of these (if they exist) would cost me?

 

[lamb]

You could fit electronic running gear in the two fittings, which may have a wider voltage tolerance.

Or you could replace the ignitors with instant start ones, so the MH lights only stay off for a couple of second when the motor starts.

 

[JD6400]

Have they had any new builds or barn conversions down the road since last winter ?
It could be within the farm's installation , and could be a loose joint or the like but i would say from the info supplied that it is more likely to be a load problem on the supply side .

 

[lamb]

But these are obviously just cheap fixes compared to installing the correct sized distribution circuit feeding motor/lights.

 

[Welshsparky86]

its whatevers cheapest really.i know,why someone would wire a 2.5mm submain at that distance i dont know, probably why ive been called there and not the guy who installed it!apparantly the supply cable from the house to the shed is warm during the milking times which clearly indicates that its working to its capacity which then gives me the headache of volt drops!ive put fluorescent lights in the sheds in the summer and they seem to be fine,but they do have electronic gear inside them. ive told the customer that its most likely down to the possibility that a new build has gone up somewhere which would affect his incoming voltage etc etc but hard to explain to the customer the ins and outs of electrical supplies!but he does remember the electricians arguing because the swa cable which feeds the sheds was apparantly too small when it was installed(pre 2004 colour changes)!!but at 231v id expect the floodlights to work,its that initial drop in voltage which interrupts them,so would electronic gear cope with the sudden drop in voltage dya rekon?

 

[JD6400]

If the ones that you installed in the summer are still working , i would say yes .
You may find that he next starts to have problems with that vac pump motor randomly cutting out .

 

[Riggy]

First thing I'd do is change the lamps, as they age they become more voltage sensitive in my experience.

If that doesn't fix it, next cheapest option would be LED floods I'd think.

I work for lots of farmers, as a rule you need to sort a few of these type of problems for them to gain their trust, then you can steer them towards cable upgrades. If you go in with an expensive solution (even if it's a better one) straight off, they'll assume you're trying to fleece them.

 

[JD6400]

Welcome along Riggy :welcome2:

 

[Welshsparky86]

haha yes,im from a farming community and know full well how they are when it comes to money!im sure if i changed the supply cable to the shed everything would be fine, but it goes underground, no ducting so it would be a big job!ill try and change the lamps first,but at a tenner a piece,they have to last longer than a year or well have to come up with a sloution!thank you!

 

[Jimsparky]

I had this same problem on a generator fed rig, everytime the compressor started up the fluorescent fittings stopped and re-started again due to the voltage dropping momentarily. I fitted LED tubes in the existing fittings as they had a wider voltage band and it solved the problem.

 

[Welshsparky86]

funnily enough, the fluoresecent are fine and just flicker when the pump kicks in, the metal hallides however go off, and unless you turn the power off to them,give it 5 mins to warm down and the re-energise them after,they wont come on!

 

[Jimsparky]

Yeah I've known them ballasts to do that before. As i think someone said earlier if you changed the floods to something like LED then I think it would be a solution to that part of the problem anyway!

 

[Guest111]

Changing lamps and fittings is a bodge anyway,considering you have already fitted flourescent lights for this farm and knowing the cable was undersized I feel you would have had a better result if you had explained in the begining that the cable was wrong rather than carrying on and having the problems later.I went on a farm just to do a small job,the guy before me had made a right B of what he had done and I had no hesitation in pointing this out to the farmer,the result was that i got all the work afterwards and the guy trusted me for being upfront.if you are not straight with him it will only bite you later,what happens if he gets another spark in when you are on holiday,it may not be your fault the cable is wrong but if someone else points it out you're going to look the fool.

 

[Knobhead]

The simple solution is a Ferro-resonant transformer to buck/boost the supply.

 

[Engineer54]

The simple solution is a Ferro-resonant transformer to buck/boost the supply.

Now that sounds expensive!! lol!!

 

[i=p/u]

Just redo you calcs for the load and cable length , you know quick fix is £100 a flood from jcc, 30w =300w equivalent

 

[plugsandsparks]

Even cheaper is a couple or 4 off 36W CF floodlights, last ones i put up were £25 a piece, cope better with the voltage dips you are getting.

 

[Nivag316]

Try firstlightdirect.com. Look under 25Watt-R7s-Low-Energy-Replacement-118mm-Long-Warm-White_A105GG.asp. Also available from Newey and Eyre for £10ish