Metal Halide lighting problem

[Jon Slaughter]

That won't stop a dangerous situation arising if there is the slightlest
glitch in the supply from any other cause, or if someone accidentally
switches the lamps off for a moment.

I've seen a similar situation in a village hall that was lit by high
pressure discharge lamps. We kept the switch on one circuit taped-over
in the 'off' position, so that we always had one cold lamp ready for a
quick re-start.

How bout a simple device that detects if the lights are on and if they
aren't simulates the manual startup process? This way if they do go off then
they will come right back on? Simply detecting current flow into the lamp
and using a fet to "hold the button" should work?

 

[Rich Grise]

The second breaker box supplies two 1000watt lights on a single 10 gauge
cable.

Then the answer is obvious - run another wire from the other phase to the
other lamp. For only 10 amps apiece, you shouldn't need much more than
#12, or even #14, if the run's not too long.

Also, wire the lamps for 220. ;-)

Cheers!
Rich

 

[Adrian Tuddenham]

How bout a simple device that detects if the lights are on and if they
aren't simulates the manual startup process? This way if they do go off then
they will come right back on? Simply detecting current flow into the lamp
and using a fet to "hold the button" should work?

The ignition circuit operates continuously as soon as the power is
restored; but the lamps won't re-strike until they have cooled and the
internal gas pressure has dropped.

 

[Jasen Betts]

Hi All,
I have a friend that has a Tuna boat, he uses two Metal Halide lights to
light up the deck. The boat has a 3 phase generator onboard.
This drives a large freezer compressor and an air compressor. When one of
the compressors comes on the lights go out, need to cool and the refire.
The lights are single phase 240 volt units.
What can be done to keep the lights working during compressor startup?
Would a constant voltage transformer such as this help?

run the motor all the time, put an electric clutch between the motor
and the compressor, actually you could put the clutch between the
power source that drives the generator and the compressor

 

[Glen Walpert]

run the motor all the time, put an electric clutch between the motor
and the compressor, actually you could put the clutch between the
power source that drives the generator and the compressor

A more practical means of reducing compressor turn-on surge would be
to use a soft starter. Google returns 3,740,000 hits for motor soft
starter. This is an extremely common problem with a lot of possible
solutions (delta-wye, reduced voltage, variable voltage and frequency
inverter type), and I would be inclined to start a search for the most
appropriate soft starter with a call to the refrigeration equipment
manufacturer.

 

[Tim Reede]

I have a friend that has a Tuna boat, he uses two Metal Halide lights to
light up the deck. The boat has a 3 phase generator onboard.

These lights have voltage taps on them like 208V, 220V, 230, 240V.

From your descriptions above, it seems like the lights run on inductive
ballasts. These are notorious for extinguishing arcs at the slightest
voltage sag and generally only work well in an environment where the voltage
is well regulated and the lamps are never exposed to vibration (yes, shaking
a HQI lamp strong enough will sometimes extinguish it). Both conditions are
hardly to be expected on a boat, rather the contrary.

Note however that both problems are much less pronounced with lamps operated
with an electronic ballast. These devices contain circuitry that essentially
amounts to a regulated switchmode power supply with active PFC. Unless the
voltage sags are particularly severe, the PFC should be able to maintain a
reasonable internal rail voltage. Also electronic ballasts run the lamps at
considerably higher operating frequencies and use a square-ish waveform thus
shortening the intervals during which the lamp current goes near zero. This
makes the arc more resistant to irregular supply as well as vibration.

While it is certain that some other backup lighting system (possibly with a
lower total power) will still be necessary to ensure the availability of
light in an emergency, your captain friend may be able to keep the metal
halides as the primary system if he replaces the inductive ballasts with
electronic ones.

Tim

 

[Rich Grise]

Hi All,
I have a friend that has a Tuna boat, he uses two Metal Halide lights to
light up the deck. The boat has a 3 phase generator onboard.
This drives a large freezer compressor and an air compressor. When one of
the compressors comes on the lights go out, need to cool and the refire.
The lights are single phase 240 volt units.
What can be done to keep the lights working during compressor startup?

Would it be prohibitively expensive to replace the electric compressor
motor with a gas (or deisel) engine?

Good Luck!
Rich

 

[amdx]

run the motor all the time, put an electric clutch between the motor
and the compressor, actually you could put the clutch between the
power source that drives the generator and the compressor