| 摘要 |
<p>A method for compensating for variations in the operating efficiency of electric motors (124, 156) used in plastic processing machines is disclosed. The current to the motor (124, 156) is continually monitored during all periods of operation to identify variations in the motor's actual efficiency as it relates to measurable machine performance. Normal operation of the electric motor (124, 156) is monitored to establish baseline current usage for the various periods (200, 226) of the operating cycle under given conditions. With a baseline established, variations in motor efficiency can be detected by monitoring the current during closed loop control (200, 226) of specific parameters and comparing the results to the baseline. Since the parameter is held constant by virtue of the closed loop, a deviation in current from the baseline indicates a change in efficiency. Based on the identified variance, the current to the motor (124, 156) during other (open loop) operations (210, 244) can be adjusted accordingly.</p> |
