Two models of generators and alternator selection

First, the generator model

There is no uniform model for the alternator that is matched with the internal combustion engine. There are two types of commonly used models :

1.5 segment symbols and numbers represent generator models

2.4 segment symbols and numbers represent generator models

Second, alternator selection

Whether the selection of the generator is reasonable is related to whether the load and the use requirements can be met after the generator is put into operation. The selection of alternator includes selection according to the use environment, selection according to load capacity, and selection according to product characteristics.

1. According to the use environment selection

This refers to the general environment and the wet tropical environment. Corresponding to the common generator and wet tropical generator, the two types of generators are suitable for the following environments:

( 1) Ordinary generators. Can be rated operation in the normal environmental conditions, i.e. continuous operation at rated speed, issued rated voltage according to the load rated power factor, the output of rated power series: altitude does not exceed 1000m, ambient temperature does not exceed 40 ℃, relative humidity Not more than 90% (at 25 ° C).

( 2) Wet tropical generators. It can be rated for operation under the following wet tropical environment conditions, that is, continuous operation at rated speed, rated voltage and output rated power according to the rated power factor of the load: altitude not exceeding 1000 m . Ambient temperature Not more than 40 ° C, the relative humidity of the air does not exceed 95% (at 25 ° C), condensation, mold. For example, ships, islands, oil fields, chemicals, food companies and other environments are all wet tropical environments.

Selection principle: Ordinary generators are used in common environments, and wet tropical generators must be used in wet tropical environments. Since the wet tropical generators must be manufactured in accordance with the requirements of wet-tropic generators in terms of component materials and processing technology, the price is slightly higher.

2. Select by load

( 1) If the load is stable, such as resistive load and resistive load, the rated power of the selected generator should not be less than the total load capacity.

( 2) The influence of ambient temperature and altitude on the output power of the generator. When the environmental conditions of the generator operating location (the above-mentioned altitude, ambient temperature, and air relative humidity) exceed the specified conditions, the output power has a corresponding influence. The higher the altitude and the higher the temperature, the greater the ratio of output power reduction and the specific reduction. See Figure 3-1 for the rate .

Example of power correction: The intersection of 45°C , 3000m horizontal axis, and ordinate line (with arrow) falls on the “12.5%” diagonal line, indicating that the power is reduced by 12.5%, that is, the output power is 87.5% PN. According to the same method above, the output powers of 40°C , 1000m, 30°C, 2000m. 10°C and 4000m are all 100% PN.

3. Selection according to product characteristics

See Table 3-2 for the structure, basic performance, reliability, economy and use of various types of generators .