Did You Know...
...that Charles Goodyear performed some of his experiments on rubber while in debtor's prison? He was there so often he referred to it as his "hotel". Chronically in debt because of poor business sense and ill health, Goodyear depended on the generosity of friends and family. Even after he unlocked the secret to vulcanizing rubber, he was unable to improve his financial situation. When he died, his estate was $200,000 in debt.
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| Number | Title | Issue Date |
| 7031091 | Magnetic recording apparatus and method of writing data at low temperature Deterioration in recording performance immediately after the start of recording in a magnetic recording apparatus due to the contraction of the magnetic head element in low atmospheric temperatures is prevented, thus ensuring a stable recording performance irrespect... | 04/18/2006 |
| 5132602 | Actuator positioning apparatus A method and apparatus for accurately and reliably positioning an actuator arm (12) is disclosed. The actuator arm (12) is driven by a conventional DC motor (38). The conductors which supply current to the motor (38) serve as primary windings (60) of a cu... | 07/21/1992 |
| 4672291 | Variable-speed electrical machine This invention pertains to an electrical machine whose excitation is coordinated to the respective rpm in such a fashion that a desired characteristic of induced voltage or delivered output is produced. For that purpose at least one portion of the winding... | 06/09/1987 |
| 4347469 | Electronic-magnetic current isolator circuit A circuit provides an electrical output signal proportional to but electrically isolated from a current flowing in a power circuit, and more particularly, to the current supplied to the field or armature winding of a DC motor load which receives power fro... | 08/31/1982 |
| 4260937 | Speed sensitive field weakening control for traction motors Disclosed herein is a control for a direct current motor including a field weakening solenoid switch including a solenoid coil, which control includes an electronic switch connected in series with the coil for selectively connecting the coil to a source o... | 04/07/1981 |
| 4250437 | Field weakening circuits for electric motors A field weakening circuit for an electric motor comprises a switching circuit the impedance of which is variable connected in parallel with a field winding of the motor. The switching circuit impedance is variable in dependence upon motor speed and curren... | 02/10/1981 |
| 4131832 | Speed sensitive field weakening control for traction motors Disclosed herein is a control for a direct current motor including a field weakening solenoid switch including a solenoid coil, which control includes a switch connected in series with a coil for connecting and disconnecting the coil to a source of direct... | 12/26/1978 |
