Safety requirements for electric parts of brakes
Because the brake is mechanical-electrical type, so it is very important to check the electrical part of the brake.
(1) Measure the temperature rise of the brake coil when the brake reaches the thermal stability state under the working voltage according to the tractor operating mechanism, load persistence rate and periodic operation. The measuring method is measured and calculated by the resistance method of Article 8.6.2 of GB 755-2008 "Quota and Performance of Rotating Motor". The temperature rise of the brake coil should not exceed 80K with class B insulation and not exceed 105K with class F insulation. For brake with bare surface temperature exceeding 6 (TC), warning signs should be added to prevent scalding.
(2) The brake coil withstand voltage test should meet the requirement of applying 1000V voltage between the conductive part and the ground, lasting lmin, and no breakdown should occur.
(3) The minimum suction voltage and maximum release voltage of the brake electromagnet should be measured after the brake temperature rise test. GB/T 24478-2009 "Elevator Tractor" stipulates that the minimum suction voltage and maximum release voltage of the brake electromagnet should be lower than 80% and 55% of the rated voltage, respectively.
(4) The newer brakes are equipped with brake-holding monitoring switches. When the brakes are abnormal, the switches will act and the elevator protects the ladder. This provides a guarantee for the safe and reliable operation of the brakes. But there is no relevant standard requirements, and I hope it will be reflected in the standards in the future for maintenance and inspection.
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