Use, maintenance and maintenance of generator set alternator

First, the safe use of alternator

1. Strict protection against leakage

(1) The insulation resistance of each winding of the generator to the ground (ie, the winding to the casing) should be checked frequently . The normal value should be greater than 2MΩ at normal temperature and greater than 0.5 in hot state (when the generator is running with load to thermal stability). MΩ. Once less than this value, the winding should be stopped for drying.

(2) Solid foreign objects, especially metal objects, must not fall into the generator. Liquids, especially corrosive liquids, must not fall into the generator.

(3) When connecting the load line, the connection should be wrapped with insulation, and the bare copper wire should not be touched.

(4) All electrical contacts should be fastened and not loose to prevent the charged body from hitting the case.

(5) When disassembling and installing the generator, do not touch the stator windings to avoid short-circuiting the windings.

2. Security protection

(1) Short circuit and overcurrent protection. The generator control panel (box) must be equipped with an air switch. When the load terminal is short-circuited or the load exceeds the rated current value specified on the nameplate, the air switch should be able to operate instantaneously (or at a specified time delay) to disengage the generator from the load.

(2) Grounding protection. Small and medium-sized generators generally use grounding protection, that is, the grounding device of the generator casing (the grounding wire for small motors) is reliably connected to the earth. When the insulation of the generator or electrical equipment is damaged, the casing can be charged to prevent electric shock.

3. Generator room environmental requirements

(1) Corrosive gases are not allowed in the equipment room to prevent accidents caused by corrosion of the generator windings.

(2) The generator should not be installed in a humid environment to prevent premature damage and aging of the generator winding insulation until leakage.

(3) The equipment room must be well ventilated to prevent the generator from overheating.

4. The generator must be used according to the operating quota

The rating of each generator operation has been marked on the nameplate and should be strictly observed. The following points must be paid special attention:

(1) The load current should not exceed the value specified on the nameplate during continuous operation. Otherwise, the rotor winding will overheat due to overcurrent.

(2) When the generator is running at full load, the engine speed must reach the rated value specified on the nameplate . The corresponding speed is found from Figure 3-2 under different loads. P N is the rated power; Æ’ N is the rated frequency. The value is specified on the nameplate; Æ’ o is the no-load frequency, and its value is specified according to the steady-state rate of the engine, generally (1 + 5%) Æ’ N . Application Example 3-2 shows: when the generator load is 25% P N, the abscissa in FIG. 25% P N at a vertical cross-primer thick solid line, and then from the lead ordinate perpendicular intersection, the intersection of value i.e. For the frequency value corresponding to 25% P N 3/4 Æ’ o- Æ’ N ) + Æ’ N , taking Æ’ N = 50 Hz and Æ’ o = 52.5 Hz as an example, find the engine speed should be adjusted at this time to make the generator frequency = 3/4 (52. 5-50) + 50 = 51. 875 Hz .

It does not allow continuous running at low speed, or excessive excitation current, rotor windings leading to overheating or even burning of the rotor windings and stator excitation, the armature winding.

Second, the maintenance and maintenance of the generator

1. Daily maintenance and maintenance

(1) Clean the generator frequently and keep the surrounding environment clean and well ventilated.

(2) Regularly check the insulation resistance of each winding. If it is lower than the specified value, it should be insulated and dried until the insulation resistance meets the requirements.

(3) The generator should not be damp. It should be covered with tarpaulin during the period of decommissioning to reduce moisture intrusion.

(4) Metal debris, water, oil, dust and various harmful gases should be strictly prevented from intruding.

(5) When the generator is running, no covering is allowed on the outer surface to avoid affecting ventilation and heat dissipation.

(6) Check the bearing temperature during operation, not exceeding 90 °C. Regularly check that the bearing grease is good. If it has changed color and hardened, clean the bearing and install new grease. The generator is generally made of lithium molybdenum disulfide grease. The amount of grease installed: the bearing chamber should be filled, and the bearing cap can only hold 1/2~2/3 of its volume . For closed bearings, the bearing chamber can only fill 2/3 to 3/4 of its volume.

(7) Always check the fastening of the conductive bolts and fasteners, and do not loosen them.

(8) Always check the surface of the brush generator collector ring for dust and grease, and whether the brush spark is abnormal. If it is not normal, it should be treated.

2. Long-term parking maintenance and care

(1) The generator should be in a normal state during long-term parking, otherwise it should be repaired.

(2) Clean the inside and outside of the generator before parking to remove dirt and dust. Inspect all fasteners, lock them if loose, and install all the covers to prevent rat and insect infestation.

(3) It is not allowed to be stored in the open air. It should be stored in a dry and well ventilated room. The room temperature should not be lower than 0 °C, and there is no water vapor and various harmful gases.

(4) Start the routine once a month to check if the performance of the generator is intact.