{"id":341,"date":"2020-11-30T10:12:37","date_gmt":"2020-11-30T09:12:37","guid":{"rendered":"https:\/\/unicompex.com\/?p=341"},"modified":"2022-11-30T07:01:48","modified_gmt":"2022-11-30T06:01:48","slug":"guide-to-buying-a-generator","status":"publish","type":"post","link":"https:\/\/unicompex.com\/en\/2020\/11\/30\/guide-to-buying-a-generator\/","title":{"rendered":"Generator buying guide"},"content":{"rendered":"

Many buyers are at a loss when it comes to buying a generating set. There are many parameters to take into account and an expert is often called in to help choose the right generator. With a competent supplier, buying can also be a pleasant and educational experience instead of a stressful and confusing one.<\/p>\n\n\n\n

Here are some questions and information to help you buy a generator. <\/p>\n\n\n\n

It's important to remember that a genset is an investment for you or your company. You need to make an informed choice and take the time to choose the right power.<\/p>\n\n\n\n

The guarantee is dependent on good dimensioning in partnership with the country representative of the chosen brand and transparency on the part of the customer regarding future use and installations.<\/strong><\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

1 - Questionnaire<\/h1>\n\n\n\n

1.1 - For which application?<\/h2>\n\n\n\n
    \n
  1. Apartment ?<\/li>\n\n\n\n
  2. Home?<\/li>\n\n\n\n
  3. Offices?<\/li>\n\n\n\n
  4. Factory?<\/li>\n\n\n\n
  5. Portable?<\/li>\n\n\n\n
  6. Small for emergencies?<\/li>\n\n\n\n
  7. Camping?<\/li>\n\n\n\n
  8. Permanent use?<\/li>\n\n\n\n
  9. Automatic system?<\/li>\n\n\n\n
  10. Location?<\/li>\n\n\n\n
  11. Diesel?<\/li>\n\n\n\n
  12. Petrol?<\/li>\n\n\n\n
  13. Hybrid with solar or batteries?<\/li>\n<\/ol>\n\n\n\n

    1.2 - For what power?<\/h2>\n\n\n\n

    Here's a rough guide to power ratings. If you don't know, give details of the equipment used, the number of inhabitants or employees, the number of offices, the number of air conditioners, etc. The best thing would be to let an expert come and measure the load per phase over 24 hours with a measuring tool (load analyser):<\/p>\n\n\n\n

      \n
    1. Portable back-up = 2-5 kVA<\/li>\n\n\n\n
    2. 1 bedroom apartment = 10 kVA<\/li>\n\n\n\n
    3. 3-bedroom house = 30 kVA<\/li>\n\n\n\n
    4. Offices 2 floors = 60 kVA<\/li>\n\n\n\n
    5. 3-storey building = 200 kVA<\/li>\n<\/ol>\n\n\n\n

      1.2.1 - Note 1 : Minimum load 30%<\/h3>\n\n\n\n

      The genset should never be run at less than 30% of its maximum load to protect the engine against cylinder glazing. Nor should the load exceed 90% of rated power for more than one hour.<\/p>\n\n\n\n

      1.2.2 - Note 2: Power types<\/h3>\n\n\n\n
      \"\"<\/figure>\n\n\n\n

      Figure 1 - The Wilson P50 FG generator has two power ratings: Prime at 45 kVA (maximum 70% for 500 hours per year) and Standby 50 kVA (maximum for 1 hour).<\/p>\n\n\n\n

      There are three types of power to specify when choosing a generating set:<\/p>\n\n\n\n

      \" <\/p>\n\n\n\n

        \n
      1. Standby: with a variable load, operates for the duration of the normal power cut, with an average standby power of 70%, up to 500 h per year. This device has no overload rating.<\/li>\n\n\n\n
      2. Peak or Prime: with a variable load operating for an unlimited period, with an average power of 70% of the main rating, a peak demand of 100% of the main rating with an overload capacity of 10% for 1 hour in 12, not exceeding 25 hours per year.<\/li>\n\n\n\n
      3. Continuous or Continue: with a constant load, the generator runs for an unlimited time, with an average of 70% to 100% of continuous power, peak demand of 100% of continuous power for all operating hours. No overload rating. <\/li>\n<\/ol>\n\n\n\n

        \"<\/p>\n\n\n\n

        From the Consulting Specifying Engineers website: https:\/\/www.csemag.com\/articles\/generator-ratings\/<\/a><\/p>\n\n\n\n

        You must always specify the power you are talking about, as there is a difference of 30% between Standby and Continuous power. <\/p>\n\n\n\n

        It's always better to slightly overestimate the load by 10% because the generating set will be useful in the near future and will therefore have to accommodate any increase in load due to the use or extension of the premises.<\/strong><\/mark><\/p>\n\n\n\n

        1.2.3 - Note 3: Design factors<\/h3>\n\n\n\n

        \"The critical parameters for sizing a generator all start with the load to be served. These parameters include:<\/p>\n\n\n\n

          \n
        1. the size of the load in kW and kVA;<\/li>\n\n\n\n
        2. the maximum permissible voltage and frequency dips that the load can withstand;<\/li>\n\n\n\n
        3. the type of load, such as motors, lighting, UPS, VFD, etc.<\/li>\n\n\n\n
        4. the nature of the service expected from the generator, i.e. is it an emergency power application or is the generator the only source of power for this load;<\/li>\n\n\n\n
        5. any reserve capacity requirements for future loads; and, of course,<\/li>\n\n\n\n
        6. voltage, phase and frequency requirements.<\/li>\n<\/ol>\n\n\n\n

          All these parameters can affect the sizing of the generator.<\/p>\n\n\n\n

          From the website : CSE link<\/a><\/p>\n\n\n\n

          1.2.3 - Note 4: Equipment starting power<\/h3>\n\n\n\n
          \"Special
          Water pumps require a high start-up load, which must be taken into account during start-up. The load can be reduced by using soft starters<\/a> (Link to the WEG website).<\/figcaption><\/figure>\n\n\n\n

          Sizing must also take into account the current demand when electrical equipment is started up.<\/span><\/strong><\/p>\n\n\n\n

          For example, if an air conditioner requires 15 kVA when it starts up because it has a compressor, but after it starts up it consumes around 5 kVA, you need to choose a genset that can handle the 15 kVA, not just the 5 kVA! <\/strong>Otherwise, the unit will never be able to start the air conditioner in question! <\/p>\n\n\n\n

          It's very important to know how much current your installations need!<\/span><\/strong><\/p>\n\n\n\n

          Equipment with reactive loads is particularly problematic, for example:<\/p>\n\n\n\n