You are not going to blow any common guage wire even with a relatively thin
guage because duration
is only at the few mS level and heat is spread out over length. However it
takes away light
output directly from flash:
A reasonable approximation for ignition resistance value for small tubes, is
something of the
order of 60V at 150A. Which translates to about 60/150 or say 0.3 Ohm. This
means the light drops
10% for every 0.03 Ohms added wire and connector resistance you add.
common small connectors are specified as capable of 6-12A continuously with a
specified maximum
resitance < 10/1000 Ohm (typ more like 5ea). This means for two connectors on
an extension cable
at the worst case values, the light would drop 20/300 or ~7%.
You can look up wire tables to determine resistance (remember wire goes there
and back, so 2X the
resistance for whatever ext length is used). Calc the resitance and do the
same exercise as above
to determine losses for the wire length and guage you choose.
I would solder, not crimp wire for the connections, although crimping works
well when done right.
In fact you can crimp and then solder for even better connection!
Tim Hughes
--- Jay Drew <dreaded@xxxxxxxxxxx> wrote:
>
> Tim,
> What would you venture the guage of the wire is that feeds the T28 flash
> heads?
> I would think that it's not 14 guage or larger for that 10's of amps. I would
> have thought the matching the wire size and voltage insulation property for a
> mid-wire splice would be the key.
>
> If I were chopping in mid-wire (and acknowledging the fact that I just blew
> the
> resale value to hell) I would think that crimp on butt splice with a judicious
> amount of electrical tape would do the trick.
>
> Johann,
> What are the subject distances and lens setups? The macro flash holder does
> limit you to a 49 / 55 mm lens but you do get 360 degree movement of the flash
> heads. Is this field use or studio stuff? Bellows or 65-116 Tube?
>
> We can get this designed for you, we can spend your money.
> Remember, our advice is free and worth what you paid for it.
>
> Jay
>
>
> >Thank you for that comment. I was actually going to ask for some advice on
> >the wire as there is a lot of current going through there I assume. I am
> >not sure however if I will cut it and splice new part into it. I would
> >rather try to make a plug & receptacle that goes between the power unit and
> >the flash head plug. But before I try any of that I am going to see if
> >moving the power unit to the front of the lens is enough for my needs (the
> >idea is to put the flash heads on goosenecks so they can be moved freely
> >around in all directions).
> >
> >J
> >
> >> Be aware if you add your own plug and cable in between, as others have
> >> suggested, it has to be
> >> low resistance wire and in case of connectors high current rated. The peak
> >> currents are well over
> >> 100A and although the connector does not have to continuously carry that,
> >> never the less, it
> >> should be rated at, at least 10's of amps.
> >>
> >> Tim Hughes
>
>
>
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