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Experts at Servicing Industrial Motors and Generators

50+ Years of combined experience…

 

Our team of seasoned professionals has more than fifty years of combined ‘hands on’ experience, which includes overhauling large high voltage motors. Our General and Production Managers work hand-n-hand with our winders and mechanics to ensure they are extensively trained and guided by industry best practices, which comply with quality standards established by Electrical Apparatus Service Association (EASA).

Additionally, formal group training is conducted to reinforce familiarization with established procedures and to introduce new techniques and technical know-how.

EASA:

As the industry’s leading trade association Electrical Apparatus Service Association is an invaluable source of information and guidance. Quality Electric Sales and Services is an active member which entitles us to access a vast index of technical information pertaining to specific motor and generator specifications.

Additionally, our membership facilitates networking with int’l motor service centers enabling us to leverage the knowledge and experience of a large pool of experts.

 

Lastly, researching industry best practices for key procedures provides us with an invaluable source for development and enhancement of our internal repair procedures designed to perfect our service.

Additionally, formal group training is conducted to reinforce familiarization with established procedures and to introduce new techniques and technical know-how.

Magnetic Wedge Experience

Quality Electric Sales and Service assures qualified repair practices in identifying special designs for repairs.

Large Electric motors are designed and manufactured quite often with magnetic wedges, which are similar in size and color to the standard Glass or phenolic wedges, this makes it very difficult to identify between the standard wedge and the magnetic wedge.

These wedges, whether magnetic or glass are used in the motor to hold down the formed coils, however, unless experienced in what to look for, the magnetic wedges can be easily overlooked and replaced in the motor with standard glass wedges.

Replacing magnetic wedges with glass wedges is a critical error as magnetic wedges are designed by the manufacturer to be a part of the magnetic circuit. If replaced with glass wedges, the effect on the motor would be a 20% increase in the magnetizing current as well as a 20 to 30 degree “C” increase in operating temperature of the motor.

Industry practice advises that for every 5 degree “C” rise in the ambient operating temperature of any Electric motor, the life of the insulation is reduced by half.

QESS identifies manufacturers’ specifications for magnetic wedges, recognizes the importance of replacing magnetic wedges and is knowledgeable on identifying the varied types and methods of installation.

Nomex Wedges

Nomex® wedges can help prevent premature motor failure and equipment downtime. That’s because Nomex® does not shrink, embrittle, soften or melt during short-term exposure to temperatures as high as 300°C, and because it maintains good insulating properties continuously at 220°C for 10 years.

Magnetic Wedges

Magnetic slot wedges are custom made to fit a specific motor and reduce starting current, improve productive and reactive power and load current, which reduces iron loss (core loss), and improves the efficiency of the motor or generator.

Laminate Sheets

High Temperature Laminates, G9/G10/G11 are used for Formed Wound Coils rated from 2,300 to 13,800 VAC. Made from epoxy resin reinforced glass fabric with extremely high temperature and mechanical strength, good dielectric loss properties and good electric strength properties.

KNOWLEDGE AND CERTIFICATION ON INVERTER RATED MOTOR REPAIR

Electric Motors required to operate at variable speeds require them to be connected to Variable Frequency Drives (VFD). However, outfitting electrical motors with VFD require a special rated copper wire on the winding.

These Electrical Motors can be identified by the name plate on the motor’s external chassis which would indicate the motor’s design for Inverter duty as seen in the above picture.

Inverter rated copper wire is manufactured at a specific texture to enabling it to cater for high voltage spikes, high noise levels and adverse environmental conditions. The wire is designed to withstand the spikes in voltage that the motor experiences during its operation connected to the VFD, for a 460 volt, three phase motor, the spike voltages could reach between 800-1200 Volts. These elevated voltages will easily damage conductor insulation on the Standard copper wire.

Therefore rewinding an Electrical Motor outfitted for VFD with Inverter rated copper wire assures motor performance to be the same as the date of Manufacture and design for intent.

NOTE a motor with VFD and wound with ordinary copper rated wire as a repair job, will experience shorts and finally a premature winding failure.

QESS technicians are certified and trained on identifying and repairing Inverter Rated Motors and therefore assure no further downtime and revenue loss as a result of not accurately assessed repair jobs.

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