N.. < ''. 



Direct-Alternating Current Transformers. 



145 



For this purpose a belt pulley is supplied at the prices given in the table, when this is required. The motor 

 efficiencies are also stated in the table. If desired, these transformers are also supplied with lower secondary 

 voltage (down to 2 volts) if it is not required to feed an arc lamp therefrom. Prices and outputs on application. 



50.677. Small Direct-Direct Current Transformer, for transforming 220 volts Direct Current s. d. 

 into 20 volts Direct Current (M. T., p. i>48): output 80 watts 9. 0. 



50.678. Regulator-Starter for previous transformer 1. 9. 



50.679. Small Direct-Direct Current Transformer, us No. 50,677, larger: output 120 watts. |ll.lO. 



50.680. Regulator-Starter for above 1. 15. 



Direct-Direct Current Transformers (cf. Fig. 50,670). for transforming 440 or 500 volts Direct Current 

 into 65 volts Direct Current. 



a 

 a 



I 



*) When ordering, kindly mention the Network Voltage; and the letters a, b, c, etc. placed before the price 

 lines, in addition to the List Numbers. 



Cf. the remarks regarding Transformers Nos. 50", 668 50,676 for 220 volts. 



Direct-Alternating Current Transformers for transforming 220 volts Direct Current into 150 volts Alter- 

 nating and about 130 volts Three Phase Current. 



o 



W 



*) When ordering, in addition to mentioning the List Numbers, kindly quote the letters a, b, c, etc. placed 

 before the price lines. 



These transformers are rotary converters: they have a commutator at one end of the armature and 4 slip rings 

 at the other. The interlinked 3-phase current can be taken off three slip rings and the single-phase alternating cur- 

 rent from two slip rings; it is also possible by using all four slip rings to obtain two-phase alternating current, this 

 current being somewhat unsymmetrical of course. 



These transformers are also supplied for connecting up to 110, 440 or 500 volts direct current, the outputs and 

 prices for 110 volts being the same as for 220. For 440 and 500 volts the speed is lo \, higher and price 5 higher. 



These machines are started as easily as ordinary direct current motors; thus, it is only necessary to move 

 the lever of the starting rheostat and the alternating of three phase current is available forthwith. A starting rhe- 

 ostat must be ordered with the transformer. The starting rheostats included in the table permit of the transformers 



10 



