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PostPosted: Sun Feb 15, 2015 7:49 pm 
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Pictures of 3 of them - that were easy to get at.

Unknown date:

Image

1998:

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1999:

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A while back I spotted some of the same type on Ebay but with an all yellow paint job.


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PostPosted: Mon Feb 16, 2015 9:25 pm 
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Hi Phosco,

Thanks for uploading your pictures of your ballasts. They are a nice neat little unit. Are these still manufactured?

Regards,

Andrew.


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PostPosted: Sun Feb 22, 2015 9:40 pm 
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Re: Davis Thyractor ballasts.

Enclosed are a few scans from a Davis Engineering catalogue from the 1990s. The Thyractor range covered 35 - 135W SOX lamps and was offered as a low loss design which would provide savings compared to traditional leak transformers.

An additional range under the Thyractor brand was designed as a retrofit component to convert existing mercury circuits to the benefits of SON.


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PostPosted: Wed Feb 14, 2018 3:37 pm 
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I've been a spark for over 30 years but never come across this type of configuration before
My local rugby club have 2000watt metal halide fittings
Many of which have failed
I've got replacement ballast /ignitors and capacitors from venture but have no idea how to connect
There is no neutral at the fitting but 2 phases ? HELP ? Ù


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PostPosted: Wed Feb 14, 2018 6:23 pm 
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All the capacitors are in a parallel.  Measure the volts on each terminal to see if one side is close/ at earth potential or if both are phase. That will tell you which is the "neutral" side as the capacitors have to be across the supply. They can't be connected actross the same phase as the voltage will be the same, they could however be across 2 phases.

On the ballast, one terminal will be at phase/live in, one terminal will connect to the lamp. The other lamp terminal must be connected to "neutral"/negative side of supply - so another way to identify the "neutral". The ballast may have a 3rd terminal which could be a supply voltage tapping or for connection to the ballast. The ballast label will say which.

The existing ignitor will have a neutral terminal - so again another way to find that common connection. If the ignitor is 2 terminal, the other will go to the lamp non neutral connection. If it has a 3rd terminal it will either connect to live in/supply or a ballast 3rd terminal. Again the label will say which.

You have terminal blocks with brown and blue in - what are the voltages on those?


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PostPosted: Wed Feb 14, 2018 11:56 pm 
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It is common practice for particularly large (often multiple) high wattage discharge lamp loads to be connected across 400V supplies. By utilising 2 out of 3 phases per lamp, better balancing of the total load can be achieved.

It is not a new technology either. My 1983 Thorn catalogue indicates a diagram for a 1500W MBIL for use on 380/415V. The total capacitor load is across the incoming two phases.

Anyway, with due respect to the logical answer already suggested (and also the chap asking the question), does the new "Venture" ballast / ignitor include any circuit diagram on a label somewhere?

Rather than trying to match up new components with the existing circuit, it might make more sense to follow the latest circuit diagram either affixed to the new gear or via Venture themselves. It will also confirm the connections for the incoming 2 phase supply either 380 or 415V, as well as the correct lamp which the gear is to operate.

Interestingly, whilst looking at the IET Forum (Institute of Engineering & Technology), the subject of 2 phase sports lighting has frequently puzzled others too.

Looking at some of the reported faults encountered with sports lighting, one of the main problems with these types of installation, is the extreme heat encountered "upstairs". The lampholders and wiring is particularly prone to damage, which in turn damages lamps and it appears, also the control gear.

If the control gear is being replaced, it might be prudent that the projector(s) are also checked for scorched / arcing lampholders / wiring / connectors.

If everything is as "factory fresh" as possible, then hopefully future problems will be reduced.

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PostPosted: Thu Feb 15, 2018 12:19 pm 
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Venture have supplied new control gear consisting of only one capacitor one ignitor and a ballast
However looking at the 4 capacitors I can not find an ignitor amongst them
The brown and blues have been used as control wiring and do not denote live and neutral as I first assumed
I will take a photo of all the new components later and if anyone can draw a circuit diagram ( idiot proof) I will endeavour to follow it
As for the lamp holders etc
We have yet to have the weather to get a cherry picker on the pitch
Thank you all so far


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PostPosted: Thu Feb 15, 2018 3:45 pm 
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I wouldn't worry about only having a single new capacitor. Multiple ones were used before as they were smaller (and cheaper).

The 2 phases are almost certainly the red and brown wires going to the capacitors.

The existing ignitor may well be remote and next to the lampholder, especially if the gear is in the base of the lighting columns.

Best to just post clear pictures of your new ignitor and ballast - there should be wiring diagrams on them and they should be a matched pair - so the diagrams on each should agree.

Where about in the UK are you?


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PostPosted: Fri Feb 16, 2018 12:02 am 
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Further to the rugby field lighting problem, the Venture Europe website does seem to be well furnished with information on the conventional, magnetic HID gear they sell. Actually, I didn't realise that Venture had bought out PARMAR in the 90s - a name which will be well known to anyone used to handling vintage SON and SOX ballasts!

They seem to have 4 main designs of multi-tap ballast for 2kW lamps. These are designed primarily for use on 380 / 400 / 415V two phase supplies.

There are also some helpful wiring diagrams, although these vary dependent on the type of ignitor to be used. I suspect this is determined by the particular metal halide lamp to be burned, such as HIT, MH-TS or MBIL lamps.

As an example, one particular ballast (HMV943383) is a conventional wirewound type. It is multi-tapped for 380 / 400 / 415V. The capacitor used is a 40uF @ 440V. Lamp current is 8.8A with a total circuit load of 2085W. Very much a general purpose ballast, it can be used on a variety of 2kW lamps (dependent on the correct ignitor being selected and designed for use on 380/440V supplies).

As has already been indicated, the existing ignitor may be inside the projector itself. Ignitors are designed to reliably strike lamps, subject to the maximum permitted lead capacitance to the lamp. It can vary between the various types and is often quite short. According to this manufacturer's data, each metre of lamp cable adds 100pF of capacitance, therefore if an ignitor has a max lead capacitance of 200pF, then that would equate to 2 metres max lead length. As I am assuming these are mounted on 10-12m columns, it is therefore likely that the new ignitor would need to be fitted into the projector as is the case already.

This is why ignitors are usually mounted as close to the lamp as possible - convenient for starting, but not so good if it is you that has to get the ladders out!

Anyway, I have enclosed a couple of screen shots of typical MH diagrams by this manufacturer. In some respects they share similarities with their 240V brethren.

The important thing is to confirm the model numbers of the replacement gear and the lamp it is intended to run. The relevant circuit diagram printed on it will then bring everything together.

Nb - it might not necessarily be like these I have included.


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