1、 Why should anchor bolts be tempered
Answer: the strength of the quenched and tempered anchor bolt is twice as strong as that of the unmodified anchor bolt.
2、 Why does the lifting motor of tower crane only go up and down
Cause analysis:
1. Open circuit in descent control line
2. The falling contactor is damaged
terms of settlement:
1. Check and fasten
2. Replace contactor
3. Replace the auxiliary contact
3、 Tower crane lifting motor no-load normal, why can not lift when loaded
Cause analysis:
1. The working power supply voltage of tower crane is too low (below 350V)
2. Weight and torque limit action
3. The braking force of lifting mechanism is adjusted too tightly
4. The voltage drop of the power supply is too large or the wiring is too loose
terms of settlement:
1. Adjust the power supply voltage
2. The lifting weight shall be controlled within the rated weight range of tower crane
3. Readjust the brake
4. Replace the circuit or check the wiring of each part
4、 Why does the tower crane's lifting motor lift heavy objects and then the heavy objects slide down after stopping?
Cause analysis:
1. Lifting brake adjustment too loose, spring failure
2. Loose and worn brake shoes
3. The brake wheel is worn and greasy
terms of settlement:
1. Readjust the brake and replace the reed
2. Replace the brake shoes
3. Replace the brake wheel and clean it
5、 Why is the lifting motor of tower crane only at low speed without high speed
Cause analysis:
1. Misoperation of weight limiter
2. Check whether the time relay or intermediate relay controlling the high and low gear switching is damaged
3. High speed gear control circuit open circuit
4. The supply voltage is low
5. High speed contactor damaged
6. Overload limit of moment limiter
terms of settlement:
1. Check and adjust
2. Repair or replace
3. Check and repair
4. Adjust the power supply voltage
5. Check, repair or replace
6. Reduce the load
6、 Why tower crane slewing motor does not start
Cause analysis:
1. Wrong action of slewing limit
2. Open circuit of slewing line
3. The slewing brake or the brake cannot be released after power failure
4. Rotary motor burnt out
terms of settlement:
1. Check the rotary stop
2. Check and repair
3. Check and repair
4. Repair or replace
