Inspection method of the hottest crane

2022-08-14
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Detection and inspection method of crane

the mechanism motor is directly controlled by the cam controller. Generally, the zero contact of the cam controller of each mechanism is all connected into the starting control circuit of the main power contactor to realize zero protection. One of the cam controllers of each mechanism is not in the zero position, and the zero contact of this cam controller is disconnected, which cannot connect the starting control circuit of the main power contactor. Only when all the cam controller handles are set to the zero position, the starting control circuit of the main power contactor coil can form a path, and the main power can be connected

if the mechanism motor is controlled by the master controller and contactor (control panel), the zero contact of the master controller is generally connected in series into the control circuit of the zero relay to realize zero protection. When the handle of the master controller is not in the zero position, the zero contact is disconnected, the control coil circuit of the zero relay is powered off, and the control circuit of the mechanism motor is dead. At this time, the main power supply can be connected. However, when the main power supply is connected, the zero relay cannot act, and the mechanism motor cannot be started at the same time

zero position protection is generally tested by power on test

the mechanism motor adopts the inspection method of direct control of the cam controller to turn off the main power supply, pull one of the controller handles away from the zero position, and then do the operation of connecting the main power supply. The main power supply should not be connected. This is because pc/abs alloy has excellent heat resistance, impact resistance and rigid connection. Put all controller handles at zero position, and the main power supply can be connected

the mechanism motor adopts the inspection method of master controller and contactor control to turn off the main power supply, pull the master controller away from the zero position, put it in the running position, and then turn on the main power supply. When the main power supply is connected, type approval refers to the administrative licensing activity conducted by the quality and technical supervision department to determine whether the type of measuring instruments meets the legal requirements. The motor of the mechanism cannot be started at the same time

(V) overload protection of motor

the rated power of the motor on the crane is greater than! $% , overload protection shall be set separately. There are many ways of overload protection, generally using overcurrent relay or circuit breaker with thermal release

overcurrent protection is the motor overload protection method widely used in cranes at present. Generally, the coil of the overcurrent relay is connected to the main circuit of the motor, and the interlocking contact is connected to the safety interlocking circuit of the main power supply or the coil control circuit of the zero position relay

in case of overcurrent, disconnect the main power supply or mechanism motor control power supply to stop the motor

the inspection of overcurrent protection is mainly the inspection of setting and setting. The installation and use unit shall conduct self inspection, and also conduct the action test of overcurrent relay

device

set and inspect the mechanisms and auxiliary mechanisms driven by diesel engine engine power supply system or squirrel cage motor, and each motor in each mechanism must be set with overcurrent protection separately. "Chen Weihong, general manager of full color plastic industry, introduced that three-phase wound asynchronous motors are allowed to be set only in two phases, and DC motors are allowed to use one overcurrent protection. The third phase of all motors is provided with general overcurrent protection, and the main power supply is disconnected during operation

the inspection of the set current value adopts the instantaneous action overcurrent relay to protect the wound asynchronous motor, and its action current is about times the rated current of the motor. The operating current of the total overcurrent protection relay of the third phase of all motors is about times the sum of the rated current of all motors of the mechanism with the largest crane capacity plus the sum of the rated current of the motors of other mechanisms that may operate at the same time. When there is a main and auxiliary hook, the auxiliary hook motor is not included in the maximum mechanism; Grab crane, lifting motor and grab opening and closing motor shall be included in the maximum mechanism at the same time

adopt the assumption that the doubt cannot be handled. The instantaneous action overcurrent relay is used to protect the DC motor, and the action current is set according to the times of the maximum allowable current of the motor. The working speed is not greater than the rated speed, and the maximum allowable current is about times the rated current of the motor when the rated power of the motor is; The rated power of the motor is, and the maximum allowable current is about times the rated current of the motor; The rated power of the motor is greater than, and the maximum allowable current is about times the rated current of the motor

when the working speed is greater than the rated speed, the maximum allowable current is about times the maximum allowable current under the above conditions

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