For businesses and homeowners who cannot afford a minute of downtime, manually operating a portable generator is simply not an option. The solution is the standby generator, a robust, permanently installed system designed to provide seamless backup power South Africa without any human intervention.
Unlike smaller manual units, a standby generator, such as our SDEC, Baudouin, and FAW diesel generators for sale, is fully integrated into your property’s electrical infrastructure. Its operation is an elegant, three-stage cycle orchestrated by one critical component: the Automatic Transfer Switch (ATS).
Here is the essential guide to how standby generators organise and deliver immediate power during a supply failure.
The Brains of the Operation – The Automatic Transfer Switch (ATS)
The ATS is the intelligence that distinguishes a true standby system from a portable generator. It is the crucial junction box installed next to your main Distribution Board (DB).
What the ATS Does: Isolation and Activation
The ATS performs two non-negotiable functions, ensuring safety and continuity:
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Constant Monitoring: The ATS constantly monitors the voltage and frequency of the incoming mains power (Eskom or municipal supply).
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Automatic Isolation (Safety): When the mains power fails (i.e., when loadshedding begins), the ATS detects the interruption and automatically disconnects the property from the grid. This action is legally mandatory (SANS 10142-1) to prevent dangerous back-feeding into the utility line.
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Activation: After isolating the property, the ATS sends a signal to the generator’s control panel, commanding the engine to start.
The ATS is the mechanism that allows the system to operate fully automatically, which is vital for commercial and industrial operations where downtime is measured in lost Rands.
The Automated Power Cycle: Three Stages
A modern standby generator executes a flawless power transition sequence that takes less than a minute from grid failure to full power restoration.
Stage 1: Detection and Start-up (The Power Fails)
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Failure Detection: The ATS senses a sustained drop or loss of voltage from the utility supply.
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Time Delay: The ATS initiates a short time delay (typically a few seconds). This prevents the generator from starting unnecessarily during fleeting voltage dips or momentary grid fluctuations.
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Engine Cranking: The ATS sends the start command to the engine control panel. The generator engine (be it SDEC or Baudouin) begins its cranking sequence, drawing power from its dedicated battery bank.
Stage 2: Transfer and Delivery (Running)
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Stabilisation: Once the engine starts, it runs up to its operating speed (usually 1500 RPM) and verifies that the output voltage and frequency (50Hz) are stable and within acceptable tolerances.
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Transfer: Once the voltage is confirmed as clean and stable, the ATS physically flips the electrical connection, transferring the property’s power load from the “Dead Mains” to the “Live Generator.”
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Operation: The generator supplies reliable backup power for the duration of the outage.
Stage 3: Shutdown and Reset (The Mains Return)
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Mains Return Detection: The ATS detects that the voltage and frequency from the utility grid have been restored and are stable.
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Cool-Down: The ATS initiates a brief cool-down cycle, allowing the engine to run unloaded for several minutes. This critical practise protects the engine from thermal shock and rapid component wear.
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Re-transfer: The ATS transfers the electrical load back to the utility grid, and the generator engine is shut down. The ATS reverts to monitoring mode, awaiting the next power failure.
The Mechanical and Electrical Core
While the ATS governs the process, the mechanical integrity of the engine and the quality of the alternator are what sustain the power.
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The Engine (The Prime Mover): The power source, typically a heavy-duty diesel engine designed for long-running hours. Brands like SDEC, Baudouin, and FAW are chosen for their industrial-grade reliability, efficiency, and proven performance under harsh South African operating conditions.
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The Alternator (The Power Generator): The engine drives the alternator, which generates the electrical current. High-quality alternators ensure the power output is clean and stable, protecting sensitive modern electronics against voltage spikes that cheaper generators often produce.
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The Control Panel: This digital interface monitors the engine health (oil pressure, temperature, RPM) and communicates directly with the ATS, acting as the system’s central processing unit.
Secure Your Compliance with Generator King’s Network
A professionally installed standby generator is the ultimate security measure against loadshedding and power failures. It requires no human interaction, provides stable power, and ensures safety through automatic isolation.
Generator King is a premium supplier and manufacturer of world-class SDEC, Baudouin, and FAW diesel generators for sale and does not perform direct electrical installations. Our expertise is in supplying, advising on compliance, and guaranteeing product quality.
To ensure your installation is safe, legal, and warranty-protected, we work closely with a national network of qualified, independent electricians who specialise in generator integration and SANS 10142-1 compliance.
Don’t leave compliance to chance. Contact Generator King today for an expert consultation on your compliance requirements and to be referred to a trusted, qualified installer in your region who can issue your essential Certificate of Compliance (COC).
By the Generator King Technical Team
