Whirling Tables. To pages 278 and 279. 



62 ' Notice. 



NEW! Whirling Table NEW! 



with Electric Motor Drive and Double Wheel Gearing. 



A. For Direct Current. 



In the construction of this new pattern Whirling Table care has been taken that the revolutions 

 of the machine can be altered within the widest limits without the power applied to the axis dimi- 

 nishing appreciably. In the case of hand-driven Whirling Tables the speed and power can be chosen 

 ;it will. If, however, the whirling table is driven by an electric motor, it generally runs at too great 

 a speed for most experiments. If the speed of the motor is decreased by inserting a resistance, the 

 power applied to the axis is correspondingly reduced, and, in addition, the speed is influenced in 

 various manners by friction. A satisfactory mode of driving is therefore unobtainable in this manner. 

 These conditions are considerably ameliorated by our fitting the machine with a simple intermediate 

 gearing which considerably decreases the speed of the motor. The machine, however, was only 

 rendered perfect by fitting it with a double gearing. There are thus two driving pulleys running at 

 different speeds at our disposal. The speed of the two pulleys is as 1 : 4. 



The gearing of the motor axis on the first driving pulley is 3 : 10. The speed of the motor 



can be further regulated within wide limits by a controlling resis- 

 tance. By selecting this arrangement it is possible to vary the 

 speed of the whirling table between 30 1100 r. p. m. From numerous 

 exhaustive experiments we have found that these limits suffice for 

 all experiments. The wheels are constructed partly of "Vulcan- 

 fibre" with a view to reducing noise to a minimum. 



8951 A. 1:9. 8951 B. 1:6. 



The whirling table has a massive iron frame and can be used both vertically and horizon- 

 tally. Fig. 8951 A shews the whirling table arranged vertically, ready for use and for taking a colour 

 disc, siren discs, or the like; while Fig. 8951 B shews the machine placed horizontally. The rotating 

 parts are constructed in the best possible manner; the axis is very carefully machined and ground 

 in so as to run true. The arrangement of the axis and the fixing of the auxiliary apparatus are 

 the same as before. Auxiliary apparatus already available fit this machine without any alteration. 



The frame is bored out laterally to the axis, and is tapped for taking different devices on 

 either one side or the other. A disc with pins for inserting in the axis of the machine, and with nut 

 for fixing siren discs, colour discs, a stroboscopic drum, or the like, also a hook fitted to the lower 

 end of the axis, for suspending pendulums, etc., are given in with each whirling table. 



The Electric Motor is fixed to the frame of the whirling table by means of a slider. The slider 

 can be moved by a screw, thus allowing the driving cord to be tightened or loosened. The regu- 

 lating resistance, a switch and a plug box are firmly fixed on the frame. This arrangement com- 

 bined everything necessary for working and the machine can be connected at once to the electric 

 supply: it is only necessary to set up the machine where it is desired to use it, connect the current 

 lead fitted to it to the electric supply with the aid of the plug contact, and the Whirling Table 

 is ready for use. No further wire connections require to be made beforehand. The weight of the 

 motor renders the machine so firm that it is only in exceptional cases necessary to screw it down 

 to the lecture table. In order to ensure the machine a firmer position and to prevent scratching 

 the lecture table, it is fitted with rubber feet. 



M. 62 6. Cl. 207. 6224. 



