| US 7,612,513 B2 | ||
| Control device equipped with motor protection function | ||
| Toru Ando, Aichi (Japan); and Tomohisa Kameyama, Aichi (Japan) | ||
| Assigned to Okuma Corporation, Aichi (Japan) | ||
| Filed on Aug. 10, 2007, as Appl. No. 11/837,020. | ||
| Claims priority of application No. 2006-232066 (JP), filed on Aug. 29, 2006. | ||
| Prior Publication US 2008/0054833 A1, Mar. 06, 2008 | ||
| Int. Cl. H02K 17/32 (2006.01) | ||
| U.S. Cl. 318—434 [318/471; 318/635] | 3 Claims |
| 1. A motor control device, comprising:
a position detecting sensor detecting an angular position of a motor;
a speed controller controlling a speed of the motor based on the angular position of the motor detected by the position detecting
sensor;
a temperature estimation component that estimates a temperature of the motor from a current command value or a torque command
value and, when the estimated temperature reaches a threshold, outputs a current cutoff signal to a current controller that
cuts off passage of current to the motor; and
an operational state determination component determining based on the angular position of the motor detected by the position
detecting sensor that the motor is in a locked state when the angular position of the motor does not change and that the motor
is in a rotating state when the angular position of the motor changes, wherein
the temperature estimation component sets the threshold as a first threshold when it is determined by the operational state
determination component that the motor is in a rotating state and sets the threshold as a second threshold, which is smaller
than the first threshold, when it is determined by the operational state determination component that the motor is in a locked
state.
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