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Question:

Thermal relays often fail

A 11kw self-priming pump, rated current 21.2A, thermal relay tuning current of 22A, cable 6 square, often jump failure, an average of ten minutes to jump, what is the reason? How to change this situation?

Answer:

First, the thermal relay often jump reasons: 1, motor overload. 2, thermal relay tuning current is too small, should be in accordance with the motor current 1.1-1.25 times the choice. 3, thermal relay selection is too small. 4, thermal relay damage malfunction. Second, the thermal relay Note: 1, thermal relay action reset after a certain period of time, automatic reset time should be completed within 5 minutes, manual reset to 2 minutes before pressing the reset button. 2, when a short circuit failure occurs, to check whether the deformation of thermal components and bimetal, if not normal, should be adjusted in time, but can not remove the components, can not bend bimetallic. 3, the use of thermal relay should be checked once a week, the specific content is: thermal relay with or without overheating, odor and discharge phenomenon, the parts of the screws whether the loose, off and disengage, surface damage and clean or not. 4, the use of thermal relay should be checked once a year, the specific content is: clean, check parts, test insulation resistance should be greater than 1 megohm, power calibration. Check the thermal relay, in addition to wiring screws, the other screws do not casually action. 5, the replacement of thermal relay, the newly installed thermal relay must meet the original specifications and requirements.
May 9, 2017
Control no problem, do not heat up the following, burn the motor will not know the power does not match, if the previous normal, that is, there can be a motor bearing or pump bearing a problem, with a fixed, check the next, I encountered a lot Load problem
May 9, 2017
With a clamp meter to measure the actual current, if the current below 22, indicating that the relay is not allowed, then adjust the point, if greater than 22, check the motor insulation, check the pump and motor bearings are not normal
May 9, 2017

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