Frequency building hoist FAQ

1. The building hoist is one of the major high-rise construction crane equipment most commonly used in building construction, the construction site is a major hazard in security checks and safety management as a key should be the focus. Past accidents and bloody lesson is profound, only in October 2008 - November, on a spate of domestic building hoist 2 from major accidents, killing 12 people and 18 people were killed and direct and indirect losses exception huge, huge irreparable damage to multiple families. In recent years, construction accidents tended to increase gradually beyond the coal industry, in addition to a traffic accident become the second largest security incidents outside the industry. Strict inspection, scientific management, prevention is the construction site construction crane safety management key, we need serious discussion and analysis.

2 construction lifts Checkpoints

2.1 Part-site inspection entity

2.1.1 base, base, fence

⑴ check whether basic parts of water, if there is evidence of uneven or sink.

⑵ mounted on one floor of the elevator, you must check the basement roof support systems and computing programs and inspection data base (including covert acceptance).

⑶ check the base, fence grounding system meets the requirements, whether the grounding resistance less than or equal 4Ω.

⑷ cage and the counterweight buffer (spring) is complete and effective.

⑸ pick tight end of the cage surrounding undamaged and height of not less than 1.8m.

With the development of science and technology, frequency control in building hoist to get more and more widely used. Frequency has a smooth start and stop the process, reduce the mechanical impact and increase occupant comfort, improve service life, but also can adjust the speed by varying the frequency of power supply, save energy, improve efficiency, but in the course of Frequency Control System It will be interference, often caused by building hoist accidents happen.

Building hoist inverter system circuit consists of two parts of the main circuit and control circuit. The main circuit consists of two parts rectifier, inverter circuit; a control circuit consists of a microprocessor, PAW trigger, PWM current controller and current feedback and other components.

Sources of interference building hoist inverter circuit block diagram of frequency control system are: overvoltage, undervoltage, instantaneous power failure inductive interference; inductive interference surge currents; inductive interference peak voltage pulse; when the weather since fog inductive interference sense currents; radio signal interference.

Building hoist inverter system after interference can cause your system is running out of control, causing the motor is running faster or slower, running up and down the cage unstable speed; the control malfunction occurs stop button and emergency stop button does not work, the motor can not stop such phenomena may cause loss of control or by falling construction elevator, causing accidents.