Inching is used in various applications such as conveyor belts, and ball mills. Inching involves short thrust of motions at reduced power.
A ball mill grinds material by rotating a cylinder with steel grinding balls, causing the balls to fall back into the cylinder and onto the material to be ground. Routine maintenance needs to be performed on these systems, and shutting down and starting up grinding mills for maintenance and inspections can be challenging and dangerous. Many companies still rely on manual techniques to move machinery through its cycles, such as jogging the start/stop button. This inefficient technique is not only hazardous for workers but potentially damaging to mechanical systems. Benshaw offers several solutions.
The Benshaw MX2 Soft Starter implements a patented slow speed algorithm that can be used to rotate a three phase AC motor with control of the stator current at speed less than the rated synchronous speed of the motor. This control method gives the three pulse cyclo converter similar performance in both harmonic output and speed range to a six pulse cyclo converter, but at a much reduced cost and much higher efficiency.
Using the Benshaw Low Voltage Drive for positioning a MV synchronous motor driven ball mill is another great solution. The Benshaw variable frequency drive powers the 4160v synchronous ball mill motor during positioning to smoothly rotate the ball mill, providing full torque at zero speed to start and rotate the mill during the positioning process. The use of a drive also provides speed adjustability to a maximum speed of 6Hz. This is 30 times the previous inching speed, allowing the maintenance setup and process time to be significantly reduced.
Electrical Solutions to Mechanical Problems
Benshaw is widely recognized as a leading provider of applied motor control technologies. We thrive on complex applications and work diligently to bring cost-effective solutions to our customers.