Isaac Newton’s (1642-1727) name will always be connected with gravity, however he did not discover or invent it, but he was the one defining it mathematically. The unit of force was named newton (N) after him. The great English scientist had a very broad scope of interest and also found practical solution for questions of seemingly less importance. In order to work without being interrupted by his pet, he is said to be the first to invent a cat flap.
 |
4 quadrant operation | ||||||||||||||||||||||||||||||||||||||||||||||
Transformers can also be used for controlling a wheel drive. Innas demonstrated this in a Lift truck, in which both the lift function and the wheel drive are controlled by transformers. The wheel drive system has to operate in all four quadrants of the drive torque vs. drive speed diagram. It must be possible to reverse both the direction of the rotation and the direction of the drive torque. Turning the control plate in the negative direction can reverse the drive torque; this causes the load and tank kidneys to change function, resulting in the load pressure being applied to the other side of the motors. In that case the make up connection to the tank is switched to the other side of the wheel motors. |
 |
|
|||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||
 |
|
|
|
|
|
|
|||||||||||||||||||||||||||||||||||||||||
