>> If you'd like to flash a landing light, just buy a three way switch and wire
it
>> to power the lamp either on all the time or through an automotive signal
flasher . . .
>>>This concept may work for low wattage bulbs, but don't try it with 120
>>>Watt halogen bulbs (such as the Bob Olds ligh kit). These bulbs have
>>>operating currents of just over 10 Amps EACH, and an inrush current in
>>>excess of 3 times that.
>An inrush current? Please correct me if I'm wrong, but I've always
>thought of a light bulb as being a purely resistive load. There's an
>instant 10 watt load when you turn it on. No load when you turn it off.
>With two 10 watt lights alternating, you have pretty much a constant
>10 watt load, with some extremley short drops to zero between during switching.
Purely resistive, yes . . . but with a very strong positive temperature
coeffecient. This is easily demonstrated by measuring the cold resistance
of any lamp. For example, I just pulled one from the drawer (NEDA #67)
and it measures 1.8 ohms in my hand. If you applied 14 volts to this
lamp, the initial reading would have to be 14.0/1.8 or 7.8 amps. However,
when I illuminate this lamp with 14.0 volts, my power suppy sez it's
drawing 0.6 amps . . . about 1/10th the "inrush" value.
>>Most heavey duty flashers are designed for switching 4-5 small bulbs
>>(ie, taillight variety).
True, even the so called "heavy" duty are unsuited for flashing
100 watt lamps. . .
>Maybe for a simple turn signal, I haven't spec'd what's available. I
>do know for a fact that police cars and ambulances have an alternate
>flash with their headlights, exactly like I would like the landing lights to
do.
Another rv-list reader suggested school bus flashers . . I belive these DO
have relays for handling increased loads. I also offer a kit of solid
state flasher and auxiliary relay. Drop me an SASE for the schematic
and bill of materials.
Regards,
Bob . . .
AeroElectric Connection
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