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WARNING! Stuff discussed here can be dangerous. High voltages here can electrocute you. Most quartz flashtubes (and a few specialty glass ones) emit shortwave and mediumwave UV. Nearly all flashtubes emit longwave UV. Large quantities of different types of UV can burn/damage different parts of your eyes and different layers of your skin. Shortwave and mediumwave UV may be hazardous in not-so-large quantities. For a greater discussion of xenon strobe hazards and safety, Go Here!
You can order this flashtube at some professional photo supply shops for approx.
US$ 150 as of 2023. One such place is B&H Photo in New York City.
This flashtube has a maximum rated flash energy of absolutely bigtime -
3200 watt-seconds. The flashtube works best at voltages slightly under a
kilovolt. I would derate the quantity of energy proportionately with
voltage below 900 volts, and not use this flashtube below 500 volts.
To make things easy on the flashtube's electrodes with heavily repeated
flashing, I recommend a maximum amount of energy (in watt-seconds or
joules) of 1,000 or 1.1111 times the voltage, whichever is lower.
As for minimum energy for efficient flashing - at least 50 watt-seconds, maybe
as much as 160 watt-seconds (updated from 100-200 on 5/15/2020)
As for maximum average power input to this flashtube? This tube can take a
beating. In free air, it seems to handle up to 200 watts OK with flash energy
between 200 and 1,000 watt-seconds and voltages of 700 to 1100 volts. Use less
average power with other voltages and other quantities of energy, or if the tube
is enclosed in something where heat will accumulate. This tube can be forced air
cooled for more power handling. Connect a small vacuum cleaner to it, and it can
probably take 600 watts long-term and a kilowatt for half a minute with
favorable energy and voltage.
As a brief torture test of this flashtube, I have given it an average
power input of 700-800 watts for a couple minutes with no forced-air cooling
(but otherwise with better-than-usual ventillation), and couldn't ruin it.
I just can't smoke it, break it, nor burn it. However, really prolonged
really heavy use is known to discolor the quartz tubing. Should you want
to exceed my recommendations and be able to tolerate some gradual tubing
discoloration or you don't need extraordinary life expectancy, GO FOR IT.
This tube can take a beating.
One thing about the Speedotron 14570/MW8QV: It triggers unusually easily.
I have been able to consistently trigger this tube with 3 and 4 KV pulses
from cheap trigger transformers. Please note that these trigger
transformers want primary voltages around 300 volts, less than the
flashtube wants. To work a cheapie trigger transformer from higher
voltages, feed the trigger capacitor from a voltage divider instead of a
resistor. For example, use 1 meg from the capacitor's positive lead to
the positive point of the energy storage capacitor, and a 470K resistor
from the capacitor's positive lead to the negative point of the energy
storage capacitor.
As for maximum voltage, I recommend against going much over a kilovolt. I
have known this tube to self-fire at 1600 volts, and inconsistently do
this or not do this. This impairs some use of this tube for short-flash
and enhanced-UV applications. This also impairs attempts to efficiently
use this tube at low flash energy but with really high voltage to get
xenon ion spectrum output.
A lower voltage serious flashtube is the Photogenic C4-5. This is the
flashtube for the Photogenic "Powerlight" 1500SL flash unit. There is a
UV-coated/color corrected version of this flashtube. This flashtube is
available with either clear or frosted glass domes with a small hole in
the top of the dome. Be sure what you are getting.
Avoid using more than 500 volts unless you want plenty of UV and a slightly
more-blue-than-average color. Also this tube draws really high peak
current (greatly exceeding a kilo-amp) at these voltages and can heat up
capacitors that don't have really low resistance.
This tube needs more trigger voltage than the Speedotron one - I recommend
6 KV trigger pulses. It usually triggers at 3 KV, but I have found
triggering below around 5 KV to not always be reliable.
This flashtube is also available at B&H, but costs a bit more than the
Speedotron one - approx. US$ 134. Update 10/13/2023 : Photogenic has
discontinued the C4-5 and replaced it with the similar C4-15 several years ago.
(Stuff on Lumedyne 090Q is deleted 10/12/2023 because this flashtube appears as
discontinued. To see this, put the URL of this web page into the Wayback
Machine.)
I have some technical info on some specific flashtubes in my Flashtube Ratings/Data/Specifications Page.
My material here on the Norman FT-6 was deleted on 7/8/2018 because of low
availability and mediocre performance. It is still available in archived
versions of this web page at the Wayback Machine, web.archive.org.
One way to get one: Find a copier with a flashtube you like. Note its
manufacturer and model number. Go to a place that sells replacement parts
for that copier, and order a replacement flashtube. Then, go to my
Xenon Strobe Design Guideline Page to determine
appropriate energy and voltage. Straight flashtubes generally do well with
really high voltages that give good efficiency at lower quantities of
flash energy - good for faster-flashing strobes.
Another way: The EG&G Heimann division, afterwards Perkin Elmer, now Excelitas
JG7905 or JG 7905. It is about 57 cm. long, has an arc length of 49 cm, and is
1 cm in diameter. It is rated for gentle use, up to 200 watt-seconds and average
input power up to either 180 or 260 watts, depending on when its manufacturer
stated a maximum flash rate with 200 joule flashes. Such gentle use allows life
expectancy of either 10 million or 15 million flashes, depending on when the
manufacturer said this, with 15 million flashes being the more recent stated
life expectancy.
This flashlamp can take greater flash energy and greater average power, at
the expense of reduced life expectancy. It cannot take as much flash energy,
flash charge in coulombs or average power as usual for quartz flashlamps of its
size because it has smaller electrodes than usual for large quartz xenon
flashlamps.
More technical details of this flashlamp (and others I mention here)
are in my flashlamp ratings and
specifications page.
Update 10/13/2023: There is the Heimann / Excelitas EG 9902. This is a
high power strobe flashlamp rated for 1500 watts and 2-14 flashes per second,
which means it is rated for strobe duty with flash energy of 107 to 750 joules /
watt-seconds.
There are also the impressive linear flashlamps often used for laser pumping,
such as ones from the former EG&G "optoelectronics electro-optics
division". The Perkin Elmer catalog for those is with the Wayback Machine here.
Quartz linear laser pump flashlamps are available on eBay.
There are the Vishay/Sprague "Powerlytic" 36DX series. These include some
nice 450 volt capacitors available in 2000, 3100, and 3500 microfarads.
You can get these from Allied Electronics and Newark Electronics. The 2,000 uF
450V ones cost approx. US$48, the 3100 uF ones cost approx. US$ 67, and the
3500 uF ones cost approximately US$74 in small quantities as of 1997 or so.
Please note that the above electrolytic capacitors generally do well only
with flash durations at least half a millisecond, preferably a millisecond.
For shorter flashes likely with repeating strobes, I recommend laser energy
storage capacitors or a bank of AC-rated motor run capacitors.
Easy ways to get 400 volts with fluorescent lamp ballasts.
Back up to my Xenon Strobe and Flash Page.
Powerful Flashtubes:
My favorite abusable flashtube is the Speedotron 14570, also known as an
MW8QV. This is the "plain quartz" (as opposed to color-corrected/reduced-UV
MW8QVC) flashtube for Speedotron's "Black Line" model 102 flash head.
Web: http://www.bhphotovideo.com/
This flashtube works best around 400-550 volts. The minimum voltage for
reliable flashing is 360 volts. It takes up to at least 1,000 watt-seconds,
and should take 500 repeatedly and have a good life expectancy. I would
derate the flash energy proportionately with voltage below 450 volts. It can
take a 150 watt average power input, 200 watts for 1 minute. Both these can
be increased by at least 50 watts with some forced-air cooling. I would
derate these figures proportionately with voltage below 500 volts.AN EVEN BIGGER OPTION FOR REPEATING STROBES!
Use one of those long flashtubes for photocopiers.Big Capacitors
UPDATE 7/23/2011: What I like now is Vishay/BC Components ones of
their 102 PHR-ST series, available at Digi-Key. I find their impedances
and effective series resistances notably low.
There are also 350 volt capacitors in this series, available in 1300,
3300, 3700, and 5100 microfarads.
Written by Donald L. Klipstein.
Copyright 1999, 2001, 2008, 2014, 2018, 2023 Donald L. Klipstein.
Please read my Copyright Notice.
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