Philips Electromagnetic Lamp manual Series connection of lamps, 123

5

3.4 Power factor correction

Mains voltage		90 %			100 %			110 %
Circuit	Ind.		Cap.	Ind.		Cap.	Ind.		Cap.
Z ballast (Ω )	440		440	400		400	360		360
Z capacitor (Ω )			800			800			800
Z result (Ω )	440		360	400		400	360		440

Therefore the behaviour of the inductive and capacitive branch of a duo-circuit is different at mains voltage deviations and deviations of the ambient temperature.This can be seen rather well in a duo-luminaire.

Fig. 116. Voltage/current characteristic of an inductive ballast (example).

V ballast (V)

180
					1			Z1	=	165	=	360 ￿
160				2
										0,458
								Z1 =		150	=	400 ￿
140										0,375
			3					Z1 =		135	=	440 ￿
120										0,307
100
80
60
40
20
	100	200	300	400	500	600	700		800		900		1000

I ballast (mA)

3 5 Series connection of lamps

Under certain conditions it is possible to operate two lamps in series on a common ballast (see Fig. 117).A prerequisite for such operation is that the sum of the operating voltages of the lamps is not higher than approximately 60 per cent of the supply voltage.This means that two lamps, each with an arc voltage of no more than 65 volt, can be connected in series via a common ballast to the 220/240 V mains.This restricts the maximum lamp length to 600 mm (2 ft), or the lamp power to 18/20 W (26 or 38 mm diameter lamps only).

The series circuit can be compensated in the normal way by using a parallel or series capacitor.

0

Fig. 117. Tandem circuit with two lamps in series on a common ballast.

‘TL’1

S

‘TL’2

S

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