Did You Know...
...Chester Carlson was a patent agent who tired of having to make multiple copies of patent applications using the only duplication method available at the time: carbon paper. In 1959 he came up with a new copying system and took it to IBM for evaluation. The "experts" at IBM determined potential sales to be only 5,000 units because people wouldn't want to use a bulky machine when they had carbon paper. Carlson's invention was the xerography process, the company founded on the system is Xerox.
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| Number | Title | Issue Date |
| 7417395 | Switch-based door and ramp interface system An interface system is presented, which prevents operational interference between a vehicle power door and a ramp of an access system by interrupting power to the motors and actuators responsible for operating the door. The interface system includes a relay system t... | 08/26/2008 |
| 6492788 | Method and apparatus for encoderless operation of a permanent magnet synchronous motor in an elevator A permanent magnet synchronous motor is controlled using d-axis current and q-axis current along with respective d-current and q-current feedback loops. The speed and position of the motor are determined by injecting a first signal into the d-axis current... | 12/10/2002 |
| 5504404 | Method and apparatus for controlling motor In a method and an apparatus for controlling a motor, one type or a plurality of types of weakening current are previously set, a first torque command current determined from a speed deviation between a speed command to the motor and the present speed of ... | 04/02/1996 |
| 4074175 | Inductive load current measuring circuit A circuit for generating a signal proportional to the average current of an inductive load supplied from a supply of intermittent electrical power and having a free-wheeling path through which load current flows during periods in which the load is not con... | 02/14/1978 |
