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| == Operation == | | == Operation == |
| These lamps are somewhat better suited for frequent switching but starting is still a major stress. They need less than two minutes to reach maximum light output and less than that to restart after being turned off. The light colour and output changes from start-up to normal operation from white to orange. White light at startup and then greenish light midway to warm-up suggests mercury is also used on the lamp. This slightly improves colour rendering but affects slightly reduces lamp life while the ones that do no change colour are either new or do not use mercury at all have a yellower light appearance. Lamps without mercury are more difficult to start but they have longer lifetimes and slightly higher efficiency.
| | It should always be remembered that low pressure sodium lamps must always be operated only in horizontal position. Leaving them on in other positions increase the risk of the lamp having a premature failure due to sodium loss as well as longer or improper operation, which also affects life. Their construction allows quick restarts with minimal reduction in light output. However, frequent starts do stress the lamp electrodes and wear do increase the risk of sodium being released slower than it should, reducing service life. The lamp should be carefully handled as it is quite fragile, especially for the higher wattage ratings, their length making them vulnerable to breaking. If a lamp breaks it should be known that sodium is very reactive and immediately rejects any water, being on a surface or in the humidity of the surrounding air. |
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| The lamp requires a conventional or electro-magnetic gear of the same power output as the lamp, connected in series with a lamp and an ignitor that must be connected as is required in the circuit. Connecting the lamp directly to mains damages it instantly as there is no current limitation. Improper connection of the ignitor is also dangerous and proper care must be exerted during installation and servicing. A power factor capacitor that has a specific value might be used to correct the power factor and current requirements on the circuit. The lamp itself is not influenced by the presence or absence of this capacitor. When used sparingly in homes or some premises where not a lot of these lamps are located, power factor correction is not important but large industrial or commercial clients were required to maintain a specific power factor due to electricity distribution contracting.
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| == Suitability == | | == Suitability == |