Comminuting machine drive system

Abstract

A comminuting machine includes a frame, a comminuting rotor coupled to the frame, and a rotary drive coupled to the rotor. The rotary drive including a controller, a multi-phase motor connected to the controller, a set of contactors disposed between the controller and the multi-phase motor for selectively providing driving motive force to the multi-phase motor, and at least one rheostat disposed between the controller and the multi-phase motor, in parallel with the first set of contactors, for selectively providing a stopping resistance to the multi-phase motor to effect frictionless braking of the comminuting rotor, wherein the controller is configured to operate the set of contactors and the at least one rheostat to single phase lines of the multi-phase motor for providing the stopping resistance.

What is claimed is: 
     
         1 . A comminuting machine comprising:
 a frame;   a comminuting rotor coupled to the frame; and   a rotary drive coupled to the comminuting rotor, the rotary drive including
 a controller, 
 a multi-phase motor connected to the controller, 
 a set of contactors disposed between the controller and the multi-phase motor for selectively providing driving motive force to the multi-phase motor, and 
 at least one load disposed between the controller and the multi-phase motor, with the set of contactors, for selectively providing a momentum resistance to the multi-phase motor opposing the driving motive force to effect frictionless braking of the comminuting rotor, 
   
       wherein the controller is configured to operate the set of contactors and the at least one load to single phase lines of the multi-phase motor for providing the momentum resistance. 
     
     
         2 . The comminuting machine of  claim 1 , wherein the controller is configured to operate the set of contactors to single phase lines of the multi-phase motor to disengage the driving motive force to the multi-phase motor. 
     
     
         3 . The comminuting machine of  claim 1 , wherein the controller is configured to operate the at least one load to single phase lines of the multi-phase motor to provide the momentum resistance to the multi-phase motor. 
     
     
         4 . The comminuting machine of  claim 1 , wherein the controller is configured such that the set of contactors is closed and contactors of the at least one load are open during operation of the comminuting rotor, where the controller is configured to control the contactors of the at least one load. 
     
     
         5 . The comminuting machine of  claim 4 , wherein the set of contactors includes a contactor for each phase of the multi-phase motor and the controller is configured to control each contactor to open one phase of the multi-phase motor and then open the remaining phases of the multi-phase motor. 
     
     
         6 . The comminuting machine of  claim 4 , wherein the at least one load includes a contactor for each phase of the multi-phase motor and the controller is configured to control each contactor to close two phases of the multi-phase motor and then close a remaining phase of the multi-phase motor. 
     
     
         7 . The comminuting machine of  claim 1 , wherein the at least one load is disposed on a stator circuit of the multi-phase motor. 
     
     
         8 . A comminuting machine comprising:
 a frame;   a comminuting rotor coupled to the frame; and   a rotary drive coupled to the comminuting rotor, the rotary drive including
 a multi-phase motor, 
 a controller connected to the multi-phase motor, 
 a first set of contactors disposed in the connection between the multi-phase motor and the controller such that each phase of the multi-phase motor includes a respective first contactor providing driving motive force to the motor, 
 a second set of contactors disposed in the connection between the multi-phase motor and the controller, with the first set of contactors, such that each phase of the multi-phase motor includes a respective second contactor, where the first set of contactors and the second set of contactors are selectably engageable, and 
 a load disposed on each phase of the multi-phase motor in-line with a respective one of the second set of contactors, 
 wherein the controller is configured to open each contactor in the first set of contactors in a first predetermined sequence and close each contactor in the second set of contactors in second predetermined sequence to provide momentum resistance opposing the driving motive force to effect frictionless braking of the multi-phase motor. 
   
     
     
         9 . The comminuting machine of  claim 8 , wherein
 the multi-phase motor is a three phase motor,   the first predetermined sequence is open a contactor of the first set of contactors on one phase and then substantially simultaneously open contactors of the first set of contactors on remaining phases, and   the second predetermined sequence is substantially simultaneously close contactors of the second set of contactors on two phases and then close a contactor of the second set of contactors on a remaining phase.   
     
     
         10 . The comminuting machine of  claim 8 , wherein the controller is configured to open the first set of contactors prior to closing the second set of contactors to provide the frictionless braking of the multi-phase motor. 
     
     
         11 . The comminuting machine of  claim 8 , wherein the load is at least one rheostat. 
     
     
         12 . The comminuting machine of  claim 8 , wherein the at least one load is disposed on a stator circuit of the multi-phase motor. 
     
     
         13 . A method for providing frictionless braking of a comminuting rotor of a comminuting machine where the comminuting rotor is driven by a multi-phase motor, the method comprising:
 controlling, with a controller of the comminuting machine, a set of contactors disposed between the controller and the multi-phase motor where the set of contactors selectively provide driving motive force to the multi-phase motor,   controlling, with the controller, at least one load disposed between the controller and the multi-phase motor, with the set of contactors, for selectively providing a momentum resistance to the multi-phase motor opposing the driving motive force to effect frictionless braking of the comminuting rotor, and   operating, with the controller, the set of contactors to single phase lines of the multi-phase motor for providing the momentum resistance to effect the frictionless braking of the comminuting rotor.   
     
     
         14 . The method of  claim 13 , wherein the set of contactors are operated by the controller to single phase lines of the multi-phase motor to disengage the driving motive force to the multi-phase motor. 
     
     
         15 . The method of  claim 13 , wherein the at least one load is operated by the controller to single phase lines of the multi-phase motor to provide the momentum resistance to the multi-phase motor. 
     
     
         16 . The method of  claim 13 , wherein the set of contactors is closed and contactors of the at least one load are open during comminuting operation of the comminuting rotor. 
     
     
         17 . The method of  claim 16 , wherein the set of contactors includes a contactor for each phase of the multi-phase motor and the method further includes controlling each contactor to open one phase of the multi-phase motor and then open the remaining phases of the multi-phase motor. 
     
     
         18 . The method of  claim 16 , wherein the at least one load includes a contactor for each phase of the multi-phase motor and the method further includes controlling each contactor of the at least one load to close two phases of the multi-phase motor and then close a remaining phase of the multi-phase motor.