Page:Motors and motor-driving (1902).djvu/332

300 through the windings of the field magnets increases the torque, and at the same time tends to check the actual speed of the motor, thereby giving what may be looked upon as an electric gearing effect.

Another point of interest is that a motor when being driven becomes a dynamo, and is capable of charging accumulators. Thus a suitable motor, when the car is running downhill, will give back current to the cells—will in fact 'recuperate' them. A good deal of misunderstanding has arisen in connection with this question of recuperation. It is



not merely that some of the energy which would otherwise be lost in friction produced by putting on the brakes is, as it were, caught and put back into the cells, but that the conditions of running are more favourable to the battery, when occasional short charges are put into it in this way, than when it is subjected to continuous discharge. The car is also rendered more controllable. It is advisable for every electric car to be provided with a voltmeter and ammeter in view of the driver's seat, so that he may know the condition of his cells and the amount of current he is taking out of them.

Fig. 11 shows a side elevation of a typical modern electric car—the 'Powerful' of the British Electromobile Co., Ltd. This car made the record long distance run in this country