In industrial environments, flexible control, energy efficiency, and low cost maintenance are all well documented benefits of variable speed drives (VSDs). However, when long cable lengths are utilized to connect VSDs to motors, motor winding insulation can deteriorate more quickly, and eventually the motor itself may fail. To understand the risks involved around this issue and the solution options available to address the situation, the technical characteristics
of the drive and the motor first need to be understood.
When electric motors are connected with Variable Speed Drives, some precautions must be taken. Motor cable length can create short time overvoltage at the motor terminal. This phenomenon results in premature ageing of the motor winding insulation, and, if not properly designed, will lead to motor failures. End users and consultants often underestimate this problem and neglect to apply best practices or to specify adequate countermeasures. This white paper provides guidance on how to avoid this potentially problematic situation.