The truck-mounted crane is one of the important components of the truck-mounted crane. Because the truck-mounted crane is dangerous, regular or irregular maintenance of it is a manifestation of responsibility for life and property.

As the core hub of modern industrial production, cranes carry more than 70% of the world’s heavy logistics operations. In the face of crane failures that are prone to occur under high-frequency operations, we can take the following measures:

1. 3-minute quick checklist

1. **Power supply check**

✅ Is the main power switch turned on?
✅ Is the circuit breaker in the distribution box tripped?
✅ Is the fuse blown? (Observe whether the metal wire in the glass tube is broken)
✅ Is the cable connector loose? (Shake the plug and listen for a “click” sound)

2. **Safety device reset**

✅ Are all emergency stop buttons popped out? (Turn clockwise to reset)
✅ Is the limit switch knocked crooked? (Check the lifting height limit and the trolley travel limit)
✅ Is the overload indicator light on? (Press the reset button after unloading the heavy objects)

3. **Operational equipment verification**

✅ Is the key switch turned to the “Start” position?
✅ Is the remote control/handle powered? (Replace the battery or charge it for testing)
✅ Is there any fault code on the control panel? (Such as E01/E02, etc.)

2. Scenario-based solutions

Scenario 1: No response at all (no light, no sound)

- **Core of the problem**: Power outage or main circuit failure
- **Steps**:
① Use a tester to check whether the power socket has power (no power → contact an electrician to repair the circuit).
② Open the crane distribution box and check whether the **main circuit breaker** is tripped (pushed back to the “ON” position).
③ If tripping occurs repeatedly → there may be a short circuit. Disconnect the load and then re-energize to test.

Scenario 2: There is power but the motor does not rotate

- **Core of the problem**: Control circuit or mechanical stuck
- **Steps**:
① Try to manually rotate the motor fan blades (cannot rotate → mechanically stuck):
- Check whether the brake is locked (tap the brake housing and listen to see if it releases with a “click” sound).
- Is there any foreign matter in the gearbox? (Clean track gravel, wire, etc.).
② If it can rotate but the motor does not start → Check the contactor:
- Press the contactor contacts lightly with a screwdriver. If the motor starts, replace the contactor coil.

Scenario 3: Tripping immediately after starting

- **Core of the problem**: Motor or line short circuit
- **Steps**:
① Disconnect the motor power cord and test it by powering it alone:
- Still tripped → Line short circuit (check if the cable insulation is damaged).
- No tripping → Motor failure (measure the three-phase resistance of the motor to ground > 0.5MΩ, which is normal).

3. Danger signals that must be watched out for!

If you encounter the following situations, please stop the machine immediately and contact professionals:
⚠️ The motor emits smoke or a burning smell
⚠️ Cable joints spark and insulation melts
⚠️ The brakes completely failed, causing the heavy object to slide down

4. Low-cost self-study skills

- **Contactor contact cleaning**: After power off, use sandpaper to polish the blackened contacts (suitable for slight oxidation).
- **Temporary emergency start**: If the limit switch fails, you can use a wooden stick to hold the limit roller to temporarily release the limit (only for low-speed and short-distance movement).
- **Remote control signal enhancement**: Wrap the base of the remote control antenna with tin foil to increase signal strength.

5. Post-maintenance verification method

1. **No-load test**: Run the machine in all directions without any heavy objects and make sure there is no abnormal sound.
2. **Load test**: hoist a weight 30% of the rated load, and test the braking slippage to be less than 80mm/min.
3. **Emergency brake test**: Press the emergency stop button during operation and the equipment should stop instantly.
If you encounter a problem that you cannot solve on your own, you can always contact us.

#Balancing valve #Pipe clamp #Throttle bracket  #Cylinder shaft #Electric control box to power harness

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