Some new hinds of fluorescent lamps recently developed such as HO Lamp, VHO Lamp, Power Groove Lamp and Double Flux Lamp, radiate more luminous flux than general line lamps. Here are discussed some problems on the fundamental design of these higher output lamps.
In Part 1 the following are described about the lamps of T-12 filled with argon gas at 2.2 mm Hg. pressure.
1. The experimental data reveal the relations heween the bulb wall temperature and the lamp characterisics for higher lamp input.
2. We may expect for higher output lamps the increase of luminous efficiency by cooling bulb wall or by lowering mercury vapor pressure. The degree of cooling effect varies according to the cooling methods, lamp input and lamp length. In this paper we discussed the following two cases of practical cooling methods.
(a) cooling by varying electrode structures and dimensions (electrode method)
(b) cooling by the side tube (side tube method)
The results are as follows:
(a) Higher the lamp input is, larger the cooling effect is.
(b) For the short lamp length the side tube method is more effctive than the electrode method, but when the lamp length is long, the difference between these two methods becomes very small.

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A new method described herein, achieves the same end as the conventional resistance method which is widely used to determine the temperature rises of discharge-lamp ballast coils.
The usual procedure is to calculate the coil temperature from coil resistance values obtained at room temperature (cold resistance) and after shutdown (hot resistance).
The new method makes possible the measurements of the hot resistance and the determination of coil temperatures while the ballasts are operating under actual load coditions in four circuits as outlined in this paper, one of them is shown in Fig 3.3 and is most widely applicable for anytype of ballasts. Refering to this figure, it is assumed that a current limiting reactor L₁ has very high inductance but low resistance and C-L is a series resonance circuit composed of a condenser and a reactor. The points where the Wheatstone bridge is connected, are of nearly same alternating potential so that the bridge is not damaged. No bridge current (d. c.) flows into the source by virtue of a condenser bank C₁ inserted in the circuit. The reading obtained on the bridge will give a combined series resistance value of the ballast and the current limitng choke coil windings. Since the resistance of L₁ is very low and of known value, the ballast coil resistance is easily obtained.
Figs 5.2 and 5.3 show the heating or cooling curves of ballast coils for 200 V 40 W fluorescent lamps.
It is believed that this new resistance method is particularly convenient to obtain the temperature rise curves of ballast coils under various conditions.

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