An electronic winch monitoring system for a winch having a fixed-ratio gearbox with input and output shafts, a winch drum connected to the output shaft, and an auxiliary brake connected to the output shaft activated by reducing the pressure in a brake release hydraulic circuit. The system comprises an input shaft speed sensor, an output shaft speed sensor, and an electronic control unit having a monitoring section and a brake control section. The monitoring section receives the speed signals, processes them to produce a calculated ratio of actual input to output shaft speeds, and produces a fault indication signal when the value of the difference between the calculated speed ratio and the fixed ratio exceeds a predetermined value. The brake control section, upon receiving the fault signal, reduces the hydraulic pressure in the brake circuit using a nonlinear pressure-time profile to engage the auxiliary brake and stop the winch drum.

Electronic winch monitoring system

A battery-powered tool (100) indicates to an operator that a torque limit has been reached. The tool comprises a driver circuit (312) for generating motor interface driving signals, a motor interface circuit (314) coupled to a motor (316) to selectively couple power to the motor in accordance with the motor driving signals, a torque limit signal generator (336) for generating a torque limit signal, a motor torque signal generator for generating a torque signal corresponding to a torque generated by the motor, and a microcontrolle (310) for comparing the motor torque signal to the torque limit signal and for generating a torque limit indicating signal in response to the torque signal being equal to or greater than the torque limit signal so the driver circuit operates the motor to vibrate to alert an operator that the torque limit has been reached.

Method and apparatus for providing torque limit feedback in a power drill

A controller for a variable frequency drive monitors electrical power from a variable frequency drive motor while a brake is maintaining a load driven or moved by the motor without requiring additional feedback components of a closed loop configuration. If excess electrical power is being generated by the motor, an undesirable condition in the brake is indicated. Support or maintenance of the load is assumed by the motor in that event. Appropriate alarms or indicators are also activated.

Method and apparatus for determining and handling brake failures in open loop variable frequency drive motors

Two incremental shaft encoders are mounted on the two extreme ends of a mechanical drive train. The encoders generate data which is representative of the rotational speed of the drive train component proximate to where the encoder is mounted. The data from the encoders is communicated to a logic unit associated with operation of the drive train, such as a variable frequency motor drive (VFD). Software in the logic unit monitors and compares the speed of both encoders. An encoder resolution setting and a gear ratio are entered into the software parameters. If a difference in speeds (as monitored and indicated by the encoders) is greater than a preset value for a period longer than a preset time period, the logic unit displays an error message and a programmed action (such as motor shutdown and load braking) is executed.

System and method for detecting a discontinuity in a mechanical drive train

A brake apparatus provided in an operating system including an electric motor as a driving source. The brake apparatus includes a brake unit section attached to an operating part in the operating system; a brake control section controlling an operation of the brake unit section; a braking condition monitoring section monitoring a braking condition of the brake unit section; and a feedback signal outputting section outputting a feedback signal representing a working condition of the electric motor. When the brake control section issues a braking command to the brake unit section, the braking condition monitoring section obtains the feedback signal, output from the feedback signal outputting section, and judges the braking condition on the basis of the feedback signal.

Brake apparatus having braking condition monitoring section

The variable frequency drive of a motor monitors pulse generator feedback while the motor is stopped and an electromechanical brake is set When the pulse generator feedback exceeds a predetermined level indicative of brake failure, tie controller actuates the motor to operate in zero servo mode and maintain the load An alarm is also sounded, allowing an operator to safely lower the load

Bradley Vinson Herron

Papers

Method and apparatus for handling brake failure in variable frequency drive motors