Criteria to choose gensets

Criteria to choose gensets

You should choose a generator in accordance with the purpose and pocket. However, you should not be eager to buy cheap genset with unknown origin. 

Before purchase a genset, you should list electrical equipment used in your family to avoid overload, short-circuit, or burning for items connected to generator. 

If your family only use genset for lighting, fans or television, you just need to buy small and medium capacity from 2 to 4 kW. And if you want to use more devices such as air conditioner, you should choose larger capacity from 4 to 6 kW. 

You should choose products suitable for the purpose and pocket. However, you should not be eager to buy cheap items with unknown origin. Capacity, warranty period, noise level and price are the most important criteria to be considered when choosing a genset. 

• Next is how to choose a generator: 

To select the correct generator, in theory, you should follow multi-step to calculate the apparent power, nominal current, consumer rating ... So this acticle only advise how to choose generator based on real power and experience. 

Before choosing a generator we need to calculate all the real power (kW) and then converted into the apparent power (kVA), , the rating factor for devices as follows: 

Type of load 

+ Power factor cos φ 
- Motor, air conditioner, refrigerator, chiller: 0.8 
- Fluorescent lamps, computers: 0.4 
- Resistance or incandescent: 1.0 

Choose 100% new generators: 
Choose a new generator with the safety factor at 1.1, that is, genset rating shall be calculated by multiplying the load capacity with safety factor. 
For example: load capacity calculated: 150KVA 
Power generators should be equipped: 150KVA x 1.1 = 165KVA 

Choose Second-hand generators: 

Depending on the status of each generator to be used, the factor of safety shall be 1.1 - 1.25 
For example: load capacity calculated: 150KVA 
Power generator used should be equipped: 150KVA - 187.5KVA depending on genset status 

• NOTE: 

- Number of devices will increase in the near future should be calculated. 
- Starting current of boot devices such as motors, compressors, etc. in water plants, timber plants ... 
- Load capacity change continuously. 
- Some loads create reverse power such as cranes, large capacity motors, elevator ... 
- You should be select genset based on continuous rating because standby rating used for 1 hour running every 12 hours. 

In the opinion of experts, most of generators in Vietnam are the ones with imported main elements, others are manufactured and assembled in Vietnam. Its advantage is reasonable price and stable quality.