Here we look closely at the first segment in a typical three-phase motor and drive system: from the mains supply at the drive input to the drive itself, concentrating on input measurements. This application note maps common problems to the measurements used to diagnose them . We show you what tools to use for a given situation and how to apply them to a problem, to enable you to troubleshoot more quickly and accurately.
Monitoring power quality parameters in a variable frequency drive or uninterruptible power supply, can help to maximize performance. Find out how to determine what power quality parameters to measure and when as well as other associated issues such as harmonic currents.
In the past, motor repair meant dealing with traditional three-phase motor failures that were largely the result of water, dust, grease, failed bearings, misaligned motor shafts, or just plain old age. But motor repair has changed in a big way with the introduction of electronically controlled motors, more commonly referred to as adjustable speed drives (ASDs).
Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). If the problem is in the centrifugal switch, thermal switch, or capacitor, the motor is usually serviced and repaired. However, if the motor is more than 10 years old and less than 1 HP, the motor is usually replaced. If the motor is less than 1/8 HP, it is almost always replaced.
Predictive maintenance (PdM) programs monitor equipment condition, with the goal of identifying problems in advance and avoiding equipment failure. One powerful tool for monitoring rotating equipment is thermal imaging.
There's an old saying that the first time you hook up a three-phase motor it will run backwards. If you're lucky, it will only make you look foolish. If you're not, it could severely damage expensive equipment and cost you or your employer substantial money.