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Mazda MB/U High Pressure Mercury |
This particular lamp was made along exactly the same lines as the mercury fluorescent products, even making use of the isothermal elliptical bulb shape which was required to keep the phosphor at a uniform temperature around the arc tube. The bulb is inside frosted to give it the pearl appearance, as this was always necessary in low wattage MB lamps to diffuse the glare of the intensely bright arc tube.
It is interesting to note the remarkably high level of quality to which the Mazda lamps were assembled, particularly in terms of their mechanical strength. Most HID lamps have their arc tubes supported on a simple wire frame, sometimes with an auxiliary support at the upper end of the bulb. The Mazda style instead made use of the 'Flare Strap' mounting style. A heavy-guage nickel-manganese wire was mechanically clamped to the side of the glass flare tube with a welded nickel strip, a thin spacer of mica in between relieving stress on the glass. The arc tube is welded to the frame wire with nickel straps and in this way, no stresses were placed on the electrical welds carrying current to the arc tube. Competitors lamps supported the arc tube on the current-carrying wires themselves and vibration damage etc frequently damaged the spot welds and caused total failure of the lamp.
| Manufacturer: | AEI Lamp and Lighting Co. Ltd. | |
| Lamp Power: | 125 Watts | |
| Lamp Current: | 1.15 Amps | |
| Lamp Voltage: | 125 Volts | For 220-250V Mains |
| Cap Type: | B22d-3/25x26 | Ni plated brass + vitrite |
| Bulb Finish: | Pearl | Soda-lime soft glass |
| Bulb Type: | E-75 | E-23½ in eighths/inch |
| Overall Length: | 183 mm | 7¼ inches |
| Light Centre Length: | 110 mm | 4 3/8 inches |
| Arc Length: | 25mm | 1 inch |
| Electrodes: | Backwound tungsten | Double carbonate emitter |
| Atmosphere: | Inner: Hg | Ar (8 atm) | Outer: Nitrogen |
| Luminous Flux: | 4,900 lm | average through life |
| Luminous Efficacy: | 39.2 lm/W | average through life |
| Colour Temperature & CRI: | CCT: 6000K | CRI: Ra 16 |
| Chromaticity Co-ordinates: | CCx: 0.315 | CCy: 0.380 |
| Burning Position: | Universal | Horiz. lumens 10% less |
| Rated Lifetime: | 7,500 hours | Rated to 70% survival |
| Warm-up & Re-strike Time: | 4 minutes | 5 minutes |
| Factory: | Leicester | England |
| Date of Manufacture: | June 1969 | Date Code: 42 |
| Original & Present Value: | £2 3s 9d (1969) | £23.69 (2005) |
