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0.5 ton electric hoist lifting structure vibration and noise troubleshooting
2014-01-19 by xiugai
A vibration fault repair

M40 - 30 type gantry crane main lifting mechanism arranged by fast motors, brakes, rolls , ZQ a 750 and a 250 2Q cylindrical gear reducer , planetary gear

Reducer , slow motor and brakes and other components. This portal cranes working on the production line at the shipyard ship .


0.5 ton Electric Hoist mechanism fast rendering system failure , whether it is empty crane hook or load , as rising and falling action , planetary gear reducer and brake frame were 5

And while occasionally produce significant abnormal vibration , and difficult to distinguish from the normal sounds abnormal noise came from the planetary gear reducer place. This vibration characteristics and failure

Common mechanical vibration factors ( such as the impact of gear , bearing the broken shaft caused the stall , mechanical coupling loss , etc.) caused by vibration is different, it does not regulate

Legal resistance, fast file system to speed when lifting and lowering has occasionally appear. And the vibration amplitude, as intermittent vibration, time is very short, each about 3-5S.

Manifestations of vibrations from the point of view , seems to be the source of the fault planetary gear reducer.

2 . Troubleshooting

In order to accurately locate the source of vibration in the field of failure to observe carefully , unlike the mechanical vibration characteristics caused by factors have obvious regularity. Temporarily not OK

Stars gear reducer disassembly and inspection , start main lifting system running fast , first with MG36 -type multi-purpose clamp meter to measure the power fast motor ; their results: whether lifting

No-load or load ? Planetary gear reducer vibration, fast motor phase current supply is unstable . Carefully check the fast motor junction box terminals and

Screw fastening , good contact, no loosening and ablation phenomenon . And then find the main lifting control panel, has found a contact arcing , which on contact Huigou more

And how points are traces of burning arc . Contacts and cut off the power to the entire control panel for cleaning, reconnect the power sanding with fine emery cloth , manipulate the system for

No-load and load repeatedly use the stall speed hoisting decline , planetary gear reducer and brake no abnormal vibration phenomenon , the fault has been ruled out.

Second, the noise fault repair


Still above the gantry crane system . Once when the ( nominal weight 40t) lifting heavy 36.ot hull segments ( corresponding amplitude range allowed ) with the main hook , the

Using fast lifting and found there was worse than usual wheel vibrations in the cab and the engine room can hear strong abnormal noise . When the high-speed gear rapidly decreased , and

No abnormal noise , then slowly lifting and lowering the load no abnormal noise heard . After unloading empty hook fast lifting and lowering noise , the second load quickly downshift from

Move, both rising high gear malfunction.

2 . Troubleshooting

Abnormal rumbling noise planetary gear reducer 5 coming out , it is easy to be mistaken on the point of failure here . However, to hear the noise components are not necessarily

Is the real source. The motor running, measured obtaining the three-phase current imbalance is the main cause of the malfunction was to find a hook fast motor power line on a terminal phase

Nut loose fitting ablation. Screwdriver with insulated handle loose lug suppress , manipulate main hook load fault conditions as the previous run , abnormal noise cancellation , replacement

Lugs , tighten the nut , troubleshooting.

Third, failure analysis

The reason these two cases vibration and noise contactor failures are bad , and the nut loose terminal phase motor running so fast caused . The second case

Lack of motors running at no load ( empty hook ) short work without fault response , humming sound emitted overshadowed by other voices , the weight of the load drop is the hull section

The role of torque , not significant faults.

( 1 ) two cases of failure exhibited failure planetary gear reducer is not a fault source ( the source of vibration and sound source ) .

( 2 ) Since the main lifting mechanism rapid motor three-phase power imbalance , the motor internally generated sequence and reverse two kinds of rotating magnetic field , the magnetic field changes

The stator and the rotor produced alternating force abnormality , it causes abnormal electromagnetic vibration of the motor .

( 3 ) rapid motor through the shaft , brake wheel couplings , ZQ a 750 cylindrical gear reducer connected with planetary gear reducer . Such differences generated by the motor

Chang vibration, sound transmission through solid process , passed to the planetary gear reducer housing , it excited vibration ; vibration frequency of the planetary gear reducer and its natural frequency phase one

Cause or octave relationship , resulting in a strong resonance. In the main lifting fast transmission system, the ZQ a cylindrical gear reducer 750 , levels shaft bearing shaft in the box

Bearing hole in the cabinets are structurally equivalent to the fixed rod set , with a stiffener board and external , internal and external structure increases the dynamic stiffness of the box , so it stimulated response

Reduced. ZQ a cylindrical gear reducer 750 base tune with relatively static , the minimum wall thickness of chaos = 15mm, made of cast iron ; while the minimum wall thickness of the planetary gear reducer 62 = 7mm,

Through cover material is A. Steel ( steel damping force is lower than the cast iron and high acoustic radiation ) , the planetary gear reducer housing cavity with only the ring gear , no ribs are thin-walled cavity

This dynamic stiffness than the former thin-walled hollow shell of smaller pieces , the possibility of forced vibration is bound to be bigger ; shell pieces . In the fast lifting action with respect to the base and around

The rotary movement and axial body vibration . Supported cantilever brakes and planetary gear reducer connected to the same base, so also will brake vibration .
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