![electric motor winding tools electric motor winding tools](https://electrical-engineering-portal.com/wp-content/uploads/2020/12/troubleshooting-typical-winding-problems-three-phase-electric-motors--920x613.jpg)
![electric motor winding tools electric motor winding tools](https://www.armaturecoil.com/UploadFiles/image/image/coil-winding-machines/model-15-L-winding-heads-wm.jpg)
These losses are a destructive factor to windings and a significant reason for bearing damage. Losses, not current levels alone, are the true source of heat. In industrial applications, perfect voltage conditions are rare. The repair for each of these three motors ran into the hundreds of thousands of dollars. This explains why these motors were failing. However, after looking at the true load to the motor, an overload of nearly 20 percent was discovered. A mild overload was identified by examining the stator current of this motor. Two identical applications had undergone unscheduled outages in the previous 12 months.
Electric motor winding tools full#
Under full load conditions, this is the difference between life and death to a motor.įor example at a coal-fired power plant in the United States, a 7000 hp 6.6kV motor was running with only 7 percent overcurrent, but an 8 percent overvoltage. A load error of more than 10 percent can be introduced by relying on stator current readings to access probable load and heat levels. It has been shown that for motors ranging from 10-200 hp, operating at a 10 percent overvoltage would typically decrease losses by only 1-3 percent.Įven though the motor current may vary when applying overvoltages, the excessive damaging heat in the motor will not improve.
![electric motor winding tools electric motor winding tools](https://sc04.alicdn.com/kf/HTB1yLQMnmYH8KJjSspdq6ARgVXa7.jpg)
A common mistake is made in operating at an overvoltage to reduce the stator current and to reduce the introduction of heat. Stator current is frequently used to measure load level, but load level can easily be masked by an overvoltage condition. There are typically five main reasons for overheating-overload, poor power condition, high effective service factor, frequent stops and starts, and environmental reasons. Articles have been published stating that a significant cause of bearing deterioration is overheating. Leading standardization organizations have concluded that 30 percent of motor failures are attributed to insulation failure and 60 percent of these are caused by overheating. As an example, if a motor that would normally last 20 years in regular service is running 40 C above rated temperature, the motor would have a life of about 1 year. The common rule states that insulation life is cut in half for every 10 C of additional heat to the windings. Maintenance experts agree that excessive heat causes rapid deterioration of motor winding insulation. Simple varnishing the rotor and stator windings is commonly used for electrical insulation and mechanical fixation but these parts do not fulfill higher requirements.Īn electric motor stator encapsulate method, including arranging a stator of an induction motor in a case of the induction motor, wherein the stator comprises a stator core and a stator winding surrounding the stator core filling a first encapsulating material into the case for forming a first insulation layer, wherein the first insulation layer directly covers the stator winding and filling a second encapsulating material into the case for forming a second insulation layer, wherein the second insulation layer covers the first insulation layer wherein a shrink rate of the first encapsulating material is smaller than a shrink rate of the second encapsulating material.On-line technologies permit assessment of the entire motor system to facilitate troubleshooting. In the electrical and electronic industry these materials are well established because of the excellent mechanical and electrical properties, the thermal durability, the chemical resistance and easy processability.Įmerging challenges for the development of motors and generators for industrial and automotive applications are size reduction, higher integration density, more power output, higher reliability and endurance, resistance in harsh environment as well as noise reduction. Since decades thermosetting resin systems based on epoxy and polyurethane have found widespread industrial applications.