Standby operation
The generator runs only when the grid power fails, for relatively limited hours, usually with an automatic transfer switch (ATS) panel that starts it and transfers the load to it automatically.
Prime operation
The generator is the site’s primary power source or runs for long hours, as at off-grid locations and construction sites.
How does this affect the choice?
- The engine’s power ratings differ between standby and prime, so the duty type must be specified when ordering.
- Prime duty usually needs a larger capacity margin and more regular maintenance.
- Fuel tank capacity and cooling options may vary by application.
Which do you need?
If the grid is available and you want protection against outages, standby is suitable. If there is no grid or operation is continuous, prime is the choice. Send us your site details and we will recommend the best fit.
Standby and prime generators compared
The choice between standby and prime generators depends on how many hours the set will run and what it is protecting. Standby generators start when the grid fails and run for a limited number of hours, while prime generators supply the main power source for a site and may run for long periods every day.
Because of this difference, engine manufacturers publish different power ratings for standby and prime duty. A set that is rated at a given output for standby may deliver less when it runs continuously at variable load. Choosing between standby and prime generators therefore changes the capacity, the cooling, the fuel tank size and the maintenance plan.
For buildings with a reliable grid, standby generators with an automatic transfer switch panel are the usual answer, and they start within seconds of an outage. For off-grid sites, construction projects and remote farms, prime generators with generous capacity margins and regular maintenance are the safer choice.
If you are not sure which duty applies, send us your site details. We will explain how standby and prime generators differ for your loads and recommend the right option in a clear quotation.
AlRyada Generators (ARG) — we supply diesel generating sets from 10 to 3500 kVA with global engine brands, plus installation, commissioning, technical support and spare parts.
Generating sets
Contact us
- Building 4, Tuilib District, Elshrouk City, Cairo, Egypt
- +2 011 53267374
- +2 011 03388485
- sales@alryada-em.com