What are the safety requirements for the electrical part of the brake?

The brake adopts mechanical-electrical type, so the inspection of the electrical part of the brake is also very important.

(1) Under the working voltage, work according to the working mechanism, load duration and cycle of the tractor. When the brake reaches a thermal steady state, the temperature rise of the brake coil is measured. The measurement method adopts GB 755-2008 "Rotating Electrical Machine Rating and Performance" 8.6.2 Resistance Method for measurement and calculation. Brake coil temperature rise shall not exceed 80K when insulation class B is used. When insulation class F is used, the temperature rise of the brake coil shall not exceed 105K. For the brake with the exposed surface temperature over 6(TC), add the warning display to prevent scald.

(2) The withstand voltage test of the brake coil shall meet the conductive part, and 1000V voltage shall be applied between the ground, lmin shall exist continuously and shall not be broken down.

(3) The absorption voltage and release voltage of the brake electromagnet shall be measured after the brake temperature rise test. According to GB/T 24478-2009 "Elevator Traction Machine", the absorption voltage and emission voltage of the brake electromagnet should be lower than 80% and 55% of the rated voltage respectively.

(4) The new brake is equipped with a brake monitoring switch, if the brake works abnormally, it will work. The elevator protects the ladder and ensures the safe and reliable operation of the brake. But there is no relevant standard requirements, so I hope to reflect it in the standard for future maintenance and inspection.

(5) Another point of the electrical part of the brake is the control circuit of the brake coil. According to the provisions of the relevant standards, it can be summarized as follows: 1 During normal operation, the brake is loose when the power is continuously applied. The interruption of the braking current, whether or not integrated with the electric device for interrupting the current of the driving machine of the elevator, applies at least two separate electric devices. Independence means that the two contactors have no mutual control relationship. The two contactors are controlled by two independent signals and cannot be controlled by one signal. After the elevator stops, if one of the main contacts in the contactor cannot be opened, the elevator should avoid running again when the next running direction changes. When the elevator motor is likely to act as a generator, the motor should be prevented from supplying power to the electrical device that operates the brake. After cutting off the release circuit of the brake, the elevator must brake effectively without further delay. The braking response time shall not exceed 5S to prevent the elevator from reversing and slipping. For the service brake with the brake element of the passenger car overspeed protection device, the response time shall meet the braking requirements in 9.10.1 of GB 7588- 2003. Even if one contact sticks to the circuit, the other contactor contact can stably separate the brake circuit and prevent slippage. The monitoring contactor does not open this fault, and other contactors do not open, so that it will not cause slippage.