Overview crane professional terms and their meanings

Cranes in the course sometimes encounter some professional terms, then we should know the meaning, in order to better use the  jib crane ,  which specific professional terms that do? What they mean?
1 brake stroke: Cranes at rated load operation, when the brake braking effect occurs after the role of inertia, will continue to exercise a distance, this distance is called brake stroke.
2 Coupling: Coupling is used to connect the agencies and pass movement and shaft torque.
3 Rated speed: refers to the motor rated frequency, rated voltage and rated power when running, rotor revolutions per minute, the unit is r / min (r / min).
4 contacts: contactor is an electrical switch for turning on and off the power, remote start or control the motor frequently, as well as making and breaking a working main circuit and control circuit.
5 Stability hook: the swinging hook smooth stop at the desired location or the smooth operation of the  Steel crane  hook with the method of operation is called stable hook.
6 Zero-voltage protection (voltage protection): Crane in operation, when the power supply is interrupted or the power supply voltage is too low, you should be able to automatically disconnect the mains, when power is restored, there should be no power to operate the joint can not be lock, to prevent self-starter motor.
7 safe distance: in a dry, non-conductive gas and dust environments, inspection and maintenance of the electrical appliances should be maintained with a minimum distance of safe distance, its value 0.35mm.
8 protective ground: that the device is not charged on the metal parts of the body through the ground with a metal link.
9 protect access to zero: the electrical equipment under normal circumstances uncharged metal parts with the grid of the zero line tight connection.
10 Over-current protection: When the main circuit or motor overload or short circuit disconnect the power on their own when a safety device.
11 Motor rated power: refers to the case of the motor is running at rated shaft can output mechanical power.
12. Compensation couplings: Allow the two shafts being coupled between a certain radial and axial displacement coupling, called compensation couplings.
13 Lifting capacity:  bridge gantry crane  lifting material allows a maximum weight referred to rated capacity. For variable amplitude crane, according to the magnitude of the rated lifting capacity crane required. Crane extract weight device itself (except hook outside the group), generally being included in the nominal weight.
14 Protective grounding: Put under fault conditions, the voltage may occur on the ground the metal parts, closely connected with the earth, known as protective ground. The grounding resistance shall not exceed 4Ω.
15 wheel load: refers to the trolley bridge crane at limit position, the bridge crane weight and nominal weight carts on wheels under the action of the maximum vertical stress.
16 Braking distance: The operating mechanism from the beginning to operate the brake to stop the spreader (or carts, trolleys) the distance traveled by.
17 Start time: at work loads, speeds from zero to rating agencies when the time required.
18 Jog: brief contact with energized to get the tiny movements.
19. Feedback: Feedback is to the amplifier output signal (voltage or current) for a part or all of the sent back to the input of the amplifier, and with the input signal phase synthesis process.
20. Pitch: rope is wound per week axial distance.
21 Run Speed: refers to the rated speed of the motor operating agencies operating under speed, with m / min (m / min) for the unit.
22 Center of gravity: the center of gravity, that is the object of the force of gravity of each part of the point of action.
23 cranes working class: the crane is a crane working level under load conditions and how busy the integrated parameters, cranes working-level grade is based on the use of cranes and crane load state to set.
24. Span: Crane carts run the distance between the centerline of the track.
25. Rectification: to convert alternating current into direct current process is called rectification.
26 Lifting height:  hoist crane  extract external device the distance between the upper and lower limits.
27 main beam camber: composed of two bridge girders are made of uniform shape arched upward, arching upward camber value is called the main beam, expressed by F.
28. Motor mechanical properties: the motor stator windings after power electromagnetic torque generated by the motor speed and the relationship between the known motor mechanical properties.