DISCOVERY 



265 



of standard design. But the forward extremity of the 

 propeller shaft, instead of terminating in the gear box 

 and being continued through it to the clutch, ends in a 

 bearing in line with the engine crankshaft. Just aft 

 of this bearing is an electric armature, and about a 

 foot rearwards of it, also on the propeller shaft, is a 

 second. Positioned round the first armature is a set 

 of electro-magnets bolted to an extension of the engine 

 fly-wheel. Positioned round the second armature is a 

 second set of field magnets attached rigidly to a casing 

 mounted on the main chassis frame. It will be seen 

 that whenever the car moves along the road, whether 

 it be pushed by hand or moves under its own power, 

 the two armatures revolve, as they form an integral part 

 of the propeller shaft. It is also obvious that the first 

 set of field magnets also revolve when the engine is 

 running and under no other conditions, and that the 

 second set of field magnets do not revolve at all. 



Assume the car to be standing still with its engine 

 running. The first set of field magnets, known as the 

 rotating field, i.e. those bolted to the engine fly-wheel, 

 are spinning round their armature, which is stationary. 

 There is, therefore, being generated in this unit electric 

 current, for armature and magnets together form a 

 dynamo pure and simple. When the controlling switch 

 on the steering wheel, about which I shall have a word 

 to say a little later on, is in the neutral position, this 

 current is as it were wasted — it is not turned to any 

 practical account ; but as soon as the switch is put into 

 the No. I position, which is that for moving the car 

 forward, the current generated in the djmamo is passed 

 to the secondary motor, which is thus energised. We 

 have now, therefore, two forces at work, both tending 

 to drive the car for^vard. The first is the magnetic 

 drag between the rotating field and its armature, the 

 second is the ordinary electric motor action in the 

 secondary motor through the fact that current is 

 being supplied to it from the first unit. 



The practical result is that the car begins to move 

 forward, and this beginning to move forward is one of 

 the most striking features of the beha\aour of this 

 wonderful car on the road. I would defy the most 

 sensitive of individuals to tell from a purely physical 

 sensation with his eyes shut when the car began to 

 move. The beginning is practically imperceptible, and 

 provided the engine be not accelerated, the rate of 

 movement is incredibly slow. As the engine is accele- 

 rated, the magnetic drag and the slip between the two 

 units of the first electrical component are increased. 

 Thus the amount of current supplied to the secondary 

 motor is also increased, and the torque or turning 

 moment conveyed to the back wheels is proportionately 

 enhanced. 



After the car has gathered speed, the controlling 

 switch is put into the No. 2 position, which is equivalent 



to a changing up in gear ratio on an ordinary car. 

 Now the magnetic drag between the rotating field and 

 its armature is increased, the slip is decreased, and so 

 is the amount of current supplied to the secondary 

 motor ; and so one goes on through the third, fourth, 

 and fifth positions, until when the controlling switch 

 is put in the last or high position the rotating field and 

 its armature are mechanically locked together. There 

 is no slip, and thus no current is supphed to the secon- 

 dary motor, the drive from engine to back wheel being 

 entirely through the primary unit. But as the arma- 

 ture of the secondary motor is revolving and its mag- 

 nets are stationary and no current is being supplied 

 to its magnets, this motor automatically becomes a 

 dynamo, and thus generates current which is passed 

 back to the primary motor and serves to ensure the 

 magnetic lock. 



It will be seen that at no time is there any positive 

 connection between engine and back axle. There is, 

 of course, an air space between the armatures and 

 their magnets, and the torque of the engine is conveyed 

 to the propeller shaft by magnetic means across this 

 air space. Thus the transmission has what may, for 

 purposes of illustration, be termed an infinite flexibility, 

 and it is impossible to get on the Crown Magnetic car 

 that feeling of jerkiness or unevenness of running that 

 is common on an ordinary car, especially at low speeds 

 and with an inferior clutch or an inexpert driver. 

 Some people who have ridden in the Crown Magnetic 

 car tell me that they seem to experience a sensation of 

 slip all the time, but I have been in the car several times 

 and I can emphatically state that this was not my 

 experience at all. I imagine that in the instances 

 referred to it was a case of auto-suggestion. The critics 

 expected to feel a sensation of slip, they made them- 

 selves feel it, and that is all. 



To deal with the control of the car from the driver's 

 point of view, this has already been covered in passing 

 in the foregoing description, but may perhaps be 

 advantageously treated explicitly. In the centre of 

 the steering wheel there is a complete circular ring, on 

 the left-hand half of which are mounted the throttle 

 and ignition levers that are found on any ordinary car. 

 It is on the right-hand side that all the Crown Magnetic 

 characteristics are to be found. Here we have a lever 

 rather larger than the ordinary throttle lever, which 

 replaces both clutch and gear lever. The quadrant 

 round which this lever works is marked C, S, N, I, 2. 3, 

 4, 5, H. To start the engine, the lever is put in the S 

 position, when the current is taken from the 24-volt 

 batteries that form an integral, although not an essen- 

 tial, component of the system to the primary motor, 

 the armature of which they energise through brushes 

 of the ordinary type, and which then turns the rotating 

 field magnets and so the engine, which is thus started in 



