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Welder generator common faults, accident handling
Sep 04, 2018

First, the abnormal operation and treatment of the Welder generator

First, the Welder generator overload:

1. Phenomenon:

1) Stator current indication exceeds rated value 2) Yes, dynamometer indication exceeds rated value

2. Cause: The stator or rotor of the Welder generator may be overloaded for a short period of time in the event of a short circuit fault, a Welder generator out of step operation, a group motor start and forced excitation. 3. Processing method:

1) System failure, monitoring the temperature of each part of the Welder generator does not exceed the limit, the stator current is the rated value. 2) The system is faultless, the single machine is overloaded, and the system voltage is normal:

A. Reduce the reactive power and reduce the stator current to within the rated value, but the power factor does not exceed 0.95, and the stator voltage is not lower than 0.95 times the rated voltage. Note that the time it takes for the stator current to reach the permissible value is not allowed to exceed the specified value.

B. If the reduction of reactive power does not meet the requirements, the length of the indication is reduced.

C. If the AC excitation regulator channel fault causes the stator to overload, the AC regulator should be switched to the DC regulator for operation.

D. Strengthen inspection of Welder generator ends, slip rings and commutators. If possible, strengthen the cooling: reduce the inlet air temperature of the Welder generator, increase the oil pump and fan of the Welder generator and transformer group.

E. During overload operation, the stator coil should be closely monitored. The cold and hot air temperatures before and after the air cooler and the unit vibration swing are not allowed to exceed the allowable value, and detailed records should be made.

Second, the Welder generator three-phase current imbalance: (gasoline power welding machine)

1. Phenomenon:

1) The stator three-phase current indications are not equal to each other, the three-phase current difference is large, and the negative sequence current indication value also increases.

2) When the imbalance exceeds the limit and exceeds the specified running time, the negative sequence signal is equipped with a “Welder generator asymmetric overload” signal.

3) Causes vibration and heat generation of the rotor.

2. Reasons: 1) The Welder generator and its circuit are disconnected in one phase or the circuit breaker is in poor contact.

2) A power transmission line is not fully operational.

3) The system single-phase load is too large: if there is a single-phase load with a large capacity.

4) The stator ammeter or meter circuit fault will also cause the stator three-phase ammeter to indicate asymmetry.

3. Treatment method: When the three-phase current of the Welder generator is out of balance, if it is determined that it is not caused by the fault of the meter circuit, the load of the unit should be reduced immediately, the unbalanced current should be reduced below the allowable value, and then reported to the system. After the three-phase current is balanced, the unit load is increased according to the dispatch command. The difference between the three-phase current of the hydro-Welder generator shall not exceed 20% of the rated current, and the current of any one phase shall not exceed its rated value. The negative sequence current that the hydroelectric Welder generator is allowed to carry shall not exceed 12% of the rated current.

Third, the Welder generator temperature is abnormal:

1. Phenomenon: The temperature of the Welder generator winding or core is obviously higher or exceeds the normal value, and the temperature of each bearing of the Welder generator is obviously higher or exceeds the normal value.

2. Reasons:

1) Measurement component failure

2) Cooling system failure: insufficient cooling water pressure, insufficient cooling water, blocked pipes, cracks or valve cores.

3) The three-phase current imbalance exceeds the limit and causes the temperature to rise.

4) The Welder generator is overloaded.

5) The cooling oil basin is insufficient in oil or the cooling water pipe is broken, resulting in water mixing in the cooling oil basin.

3. Processing:

1) Determine whether it is a meter or a measuring point fault: Yes, notify the maintenance process, and exit the fault measuring point, and closely monitor the temperature of other measuring points.

2) If the meter or measuring point indication is correct and the temperature rises sharply, the load is reduced to bring the temperature down to the rated value. Otherwise stop processing.

3) Check whether the three-phase current is balanced, whether the unbalanced current is over-limit, and if it exceeds the limit, it is processed according to the three-phase unbalanced current.

4) Check if the three-phase voltage is balanced, if the power factor is within the normal range, and if it does not meet the requirements, adjust to normal.

5) Determine whether it is caused by a cooling water failure. If the cooling water temperature rises, check and adjust the flow rate and pressure of the cooling water within the normal range.

6) If it is caused by overload, handle it in overload mode. 7) If the cooling water pipe is broken, close the corresponding valve and stop the treatment.

8) During operation, the temperature of the stator core is generally increased: check whether the three-phase current of the stator is balanced, the temperature difference between the inlet air temperature and the outlet air, and whether the cooling water of the air cooler is normal, and take corresponding measures for treatment. In the above process, the temperature of the stator core should not be controlled to exceed the allowable value, otherwise the load will be stopped.

9) During operation, the individual temperature of the stator core suddenly rises: the trend of temperature rise at this point and the relationship with the reactive load and reactive load should be analyzed, and whether the measuring point is normal is checked. If the temperature of the core, the temperature difference between the inlet and outlet air rises significantly, and the "stator grounding" signal appears, the load should be immediately decomposed and stopped to avoid the core burning out.

10) During operation, the individual temperature of the stator core drops abnormally: the inspection of the Welder generator body and the air-cooled chamber and the temperature monitoring should be strengthened, and various external signs, meters and signals should be analyzed to determine whether the Welder generator rotor or stator is leaking. So far. 

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