Motor Starting Studies
Starting large motors, especially across the line, can cause severe disturbances to the motor, any locally connected load and to buses electrically remote from the point of motor starting.
This report needs to be done when:
- starting voltage requirement and preferred locked-motor current is stated as part of motor specification
- motor horsepower exceeds approximately 30% of the supply transformer(s) base kVA rating if no generators are present
- if daily fluctuation of nominal voltage level, size and length of the motor feeder cable, amount of load, regulation of the supply voltage, importance and tap rating of the supply transformer(s), load torque versus motor torque and the allowable starting time are in focus
This study determines:
- The Voltage Drop Snapshot: Examining the effect of voltage dip during motor starting to ensure the maximum instantaneous drop that occurs leaves bus voltages at acceptable levels throughout the system.
- The Detailed Voltage Profile: Allows a more exact examination of the voltage drop situation.
- The Speed-Torque and Acceleration Time: Provides electrical and acceleration torque calculations for speed time intervals during the motor starting period.
