Max Kohl A. G., Chemnitz, Germany. 



Net- 

 work 



Ammeter 



II. Grouping as 

 a Shunt Resistance. 



To the Apparatus 



Grouping No. II. As a Shunt Resistance, Fig. 4, for taking off any Currents (within the limits of load) 

 at low Pressure. 



It is advisable first of all to place 

 Switch Contact /. on the highest resistance- 

 value and Contact //, on "O", the latter 

 being moved forward until the desired 

 current-density is reached. 



If Switch Contact //. is still near 

 to "O" and should a further slight increase 

 in the current still be necessary, it is better 

 to move Switch Handle /. back than No. //. 

 forward. In feeding apparatus which work 

 with an interrupted current (e. g. induction 

 coils with platinum interrupters) too high 

 a tension should not predominate when the 

 current is admitted otherwise there is danger 

 of the contacts getting burned. When heavy 

 currents are being used, Switch Contact No. //. should be left near to O and Contact /. moved back 

 cautiously. The pressure at the apparatus when the current is being admitted is to the working voltage 

 as the resistance-values given alongside the contact studs on which the Handles are placed are to each other. 

 The maximum permissible currents given under (1) should in no case be exceeded. 



Grouping No. III. As a Shunt Re- 

 sistance, Fig. 5, for taking off small Currents .!?",". 4 (C ^ Ammeter 

 up to 2 Amps. 



As a rule both Switch Contact Handles 

 are first of all placed on the zero contacts, the 



III 



Grouping as Shunt 



Resistance 

 for small currents. 



To the Apparatus 



current in the apparatus being slowly increas- 

 ed by adjusting one of the Contact Handles. 



If Handle No. //. is placed on the spot 

 where No. /. previously stood, and vice-versa, 

 this changes the poles at the apparatus. 



Under no circumstances whatever 

 must this method of grouping be used for 

 taking off higher current- densities than 2 

 Amps. A too heavy current - - with con- Fig. s. 



sequent burning out of the resistances - - is particularly liable to take place when one Handle is near the 

 highest resistance-value and the other close to the zero-value and the resistance of the apparatus itself is 

 small. The latter would cause most of the spirals to short-circuit and the thin spirals, in series, near to 

 the maximum resistance-value would then be charged with a current exceeding that prescribed. 



It is always advisable (as also in the case of other methods of employing the resistances) to connect 

 up a reliable ammeter for protecting the resistance and the apparatus connected up. The total current flowing 

 through the resistance, when connected up in accordance with Scheme No. ///. should not exceed 5 Amps. 



PRICES. 



50516. Experimental Resistance, Type A, Fig. 1, with 2 Switch Handles, 39 Contacts; Resistance 

 36 Ohms; maximum permissible load, 5 to 30 Amps., according to position of Contact 

 Handles; for taking currents of 0.03 to 30 Amps, and pressures of 0.3 to 110 Volts from 



the supply line .'6.15.0. 



50517. Experimental Resistance, Type B, Fig. 1, with 2 Switch Handles, 39 Contacts; Resistance 

 48 Ohms; maximum permissible load 5 to 20 Amps., according to the position of the Switch 

 Handles; for taking currents of 0.08 to 20 Amps, and pressures of 0.8 to 220 Volts from 



the supply line ,,6.15.0. 



50518. Experimental Resistance, Type C, Fig. 2, with 2 Switch Handles, 39 Contacts; Resistance 

 24 Ohms; maximum permissible load, 5 to 20 Amps, according to the position of the Switch 

 Handles; for taking currents of 0.08 to 20 Amps, and pressures of 0.8 to 110 Volts from 



the supply line ,4.1.0.0. 



