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Pulse Start
The most common HID lamps are metal halide (MH) and high pressure sodium (HPS). Efficacy in lumens-per-watt (LPW), lamp life, and cost are economic characteristics of a HID lamp which can be analyzed objectively. Color and color rendering properties, however, are much more subjective. The photo shows a facility with two types of systems.
 Left side of picture: 400 watt low bay aluminum HPS fixtures (yellow light source) with a Color Rendering Index (CRI) of 25. Lamp: 50,000 initial lumen. Fixture wattage: 464 Watts
Right side of picture: 400 watt high bay glass MH fixtures (‘white’ light source) with a CRI of 65. Lamp: 36,000 initial lumen. Fixture wattage: 458 Watts.
Metal halide systems are the preferred HID source for applications where color rendering is important. It is common for workplaces with 400 watt HPS systems to be retrofitted to a 400 watt MH systems.
What is Pulse Start?
A change in the lamp and ballast construction allows pulse start metal halide lamps to start using a high voltage ignitor in the ballast instead of a starting electrode (probe) in the lamp. The result is a "white light" system that challenges high pressure sodium’s long lamp life, high lumen output and quick starts capabilities.
| Benefits of Pulse Start HID Ballast/Lamp System! |
| Longer lamp life |
Better lumen maintenance |
Reduced color shift |
| Superior color rendition to HPS |
Improved lamp-to-lamp color consistency |
Faster warm-up time |
| Faster restrike time |
Colder starting temperatures |
Less arc tube blackening |
Lamp:
Probe Start Lamp
A traditional or probe start metal halide lamp has an internal starting electrode or probe. A high open circuit voltage from the ballast initiates an arc between the two starting electrodes at one end of the arc tube. Once the lamp reaches full output, a bi-metal switch closes to short out the probe and discontinues the staring arc.
Pulse Start Lamp
A pulse start lamp has an improved arc tube design and an increased fill pressure. An ignitor in the pulse start system delivers a high voltage pulse directly across the lamp’s operating electrodes to start the lamp, eliminating the probe and bi-metal switch needed in probe start lamps.
Ballast:
CWA - Constant Wattage Autotransformer (lead-type regulator), the most widely used HID ballast today, offers good ballast regulation and moderate ballast losses. Available for probe start metal halide and high-pressure sodium lamps.
Pulse Start Ballast -The pulse start system uses a dedicated ballast that includes an ignitor. This eliminates the need for the starting probe and bi-metal switch in the lamp. There are three designs of pulse start ballasts, each has it’s own characteristics. As in all ballast designs, the ballast must match the electrical requirements of each specific lamp. The American National Standards Institute (ANSI) has applied specific identification codes to each pulse start system.
SCWA – Super Constant Wattage Autotransformer, the pulse start version of the CWA ballast, offers good ballast regulation and moderate ballast losses. For pulse start metal halide lamps only.
LLSCWA – Low Loss Super Constant Wattage Autotransformer, this ballast has all the benefits of an SCWA ballast, but with reduced energy consumption. For pulse start metal halide lamps only.
LLRPSL – Linear Reactor, designed as an energy savings system, 277-volt only, is used in areas with very little line voltage variation. Auxiliary quartz options are not available. For pulse start metal halide lamps only.
RLB – Regulated Lag Ballast (LAG-type regulator, "reg-lag"), exhibits the best ballast regulation, is used in areas where excellent line dip tolerance is critical. For pulse start metal halide lamps only.
The Pulse Start calculator allows you to compare a Probe-Start HID system with a Pulse Start HID Ballast/Lamp System based on energy savings and mean lumens for enclosed rated lamps. All input watts, and mean lumens data are based on the most recent information. The calculations show the potential economic savings of a proposed system based on the following input wattage and vertical lamp lumen output shown in these charts. Please refer to the lamp manufacturer’s data sheets for precise lamp performance. All calculations use mean lumens, the lumen output of a lamp after it has operated for approximately 40% of its rated life.
The Pulse Start Calculator Excel (Version '97) allows users to choose a wider range of available HID systems (recommendations are not available), moreover calculates simple payback on estimated initial capital cost.
| Standard HID System |
Input Wattage |
Initial lumens
(Clear Lamp) |
Mean lumens
(Clear Lamp) |
Average Rated Life |
| 250W Metal Halide (CWA) |
295 |
22,000 |
17,000 |
10,000 |
| 400W Metal Halide (CWA) |
458 |
36,000 |
23,500 |
22,000 |
| 1000W Metal Halide (CWA) |
1080 |
110,000 |
86,000 |
18,000 |
| Pulse Start HID System |
Input Wattage |
Initial lumens
(Clear Lamp) |
Mean lumens
(Clear Lamp) |
Average Rated Life |
| 200W Metal Halide (LLRPSL) |
218 |
21,000 |
16,800 |
15,000 |
| 200W Metal Halide (SCWA) |
232 |
21,000 |
16,800 |
15,000 |
| 200W Metal Halide (RLB) |
244 |
21,000 |
16,800 |
15,000 |
| 250W Metal Halide (LLRPSL) |
275 |
25,000 |
20,000 |
15,000 |
| 250W Metal Halide (SCWA) |
288 |
25,000 |
20,000 |
15,000 |
| 250W Metal Halide (RLB) |
298 |
25,000 |
20,000 |
15,000 |
| 300W Metal Halide (LLRPSL) |
324 |
30,500 |
24,400 |
20,000 |
| 300W Metal Halide (SCWA) |
342 |
30,500 |
24,400 |
20,000 |
| 320W Metal Halide (LLRPSL) |
349 |
33,000 |
26,400 |
20,000 |
| 320W Metal Halide (LLSCWA) |
350 |
33,000 |
26,400 |
20,000 |
| 320W Metal Halide (SCWA) |
370 |
33,000 |
26,400 |
20,000 |
| 350W Metal Halide (LLRPSL) |
380 |
37,000 |
29,600 |
20,000 |
| 350W Metal Halide (SCWA) |
400 |
37,000 |
29,600 |
20,000 |
| 400W Metal Halide (LLRPSL) |
435 |
42,000 |
32,800 |
20,000 |
| 400W Metal Halide (LLSCWA) |
434 |
42,000 |
32,800 |
20,000 |
| 400W Metal Halide (SCWA) |
455 |
42,000 |
32,800 |
20,000 |
| 400W Metal Halide (RPB) |
467 |
42,000 |
32,800 |
20,000 |
| 450W Metal Halide (LLRPSL) |
485 |
50,000 |
40,000 |
20,000 |
| 450W Metal Halide (SCWA) |
514 |
50,000 |
40,000 |
20,000 |
| 450W Metal Halide (RPB) |
530 |
50,000 |
40,000 |
20,000 |
| 750W Metal Halide (SCWA) |
818 |
82,000 |
60,000 |
16,000 |
| 875W Metal Halide (SCWA) |
940 |
100,600 |
80,500 |
12,000 |
| 1000W Metal Halide (SCWA) |
1080 |
120,000 |
96,000 |
15,000 |
New installation fixture count is based solely on lumen data, but this is only an approximate count. Total actual fixture count for a new installation may vary depending on actual conditions, such as maintenance factors, room cavity ratios, etc... The calculator is not intended to replace an application software program (Visual 2.0), that will provide an accurate fixture count.
Start the Pulse Start Calculator
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