Changes in voltage have a significant impact on current. When it comes to supply voltage variations, starting current and running current respond very differently. A drop in line voltage will result in a lower starting current and a higher running current. A rise in line voltage up to 5% will increase starting current and slightly reduce running current. If the line voltage increases more than 5%, both starting and running current will be higher. As a general rule of thumb a 1% voltage imbalance can create a 7% current imbalance and a motor with a 5% voltage imbalance has a reduced capacity of 25% and should not be run unless the motor is de-rated accordingly.
Visit the PdMA YouTube site at https://www.youtube.com/channel/UC-cUONWaudkKReNwC0PPXMQ to see a variety of case studies from the electric motor reliability industry.