AGP Generators carries out resistive load bank testing on diesel generator sets across South Africa to prove real capacity rather than nameplate assumption. A generator that has never run under load is a backup in hope only, because low-load running causes wet stacking where unburned fuel coats the exhaust and cylinders. Each test issues a written report recording voltage, frequency, step-load behaviour and defects, with annual testing recommended for standby sets.
What is included
Resistive load bank hire and connection
Step-load test sequence
Voltage and frequency recording
Exhaust and temperature monitoring
Wet stacking inspection
Written test report
Defect and recommendation list
How we work
1
Pre-test inspection
We inspect fluids, battery, leaks and alarm state before connecting the load bank, so the test does not damage a set that was already marginal.
2
Load bank connection
A resistive load bank is cabled to the set output and configured to the rated kVA in stepped increments.
3
Step-load test
The set is loaded in steps to 25, 50, 75 and 100 per cent, with voltage, frequency and recovery recorded at each step and after load dump.
4
Wet stacking inspection
Exhaust smoke and cylinder condition are checked for the wet, oily deposits that signal low-load running and incomplete combustion.
5
Written report
A written test report records the results, flags any defects and recommends the next test date, typically annual for standby sets.
Why a generator that has never run under load is an assumption
Standby sets spend most of their lives off. A weekly no-load start proves the engine turns and the controller is alive, but it proves nothing about whether the set can carry its rated load for the duration an outage demands.
Only a load bank test applies real electrical load and exposes the failures that hide in idle sets: weak alternator excitation, fuel starvation under demand, cooling limits and AVR recovery behaviour. A set that passes a load test is a backup; one that has not is a hope.
Wet stacking and low-load running
Diesel engines are designed to run hot under load. When a set runs for long periods at little or no load, combustion temperatures stay low and unburned fuel condenses in the exhaust and cylinders. This is wet stacking, and it leaves wet, oily deposits that foul injectors, glaze cylinder liners and reduce the set to a smoky, unreliable shadow of its rating.
A load bank test burns off these deposits and confirms the set can reach operating temperature under real demand. For sets that must run light, periodic load banking is the corrective, not a luxury.
What it costs
Pricing for load testing depends on the factors below. We quote in writing so the full cost is visible before any work starts.
Generator kVA rating
Load bank size and hire
Site access and cabling distance
Travel from depot
Report format requirements
Number of sets tested
Sectors we serve
Healthcare and hospitalsData centres and telecomsMining and quarryingManufacturing and industrialGovernment and municipalRetail and shopping centresResidential estatesHospitality and lodges
A resistive load bank is cabled to the generator output and applies real electrical load in steps to 100 per cent of rating, proving the set can carry its rated load and exposing faults that hide in idle standby sets.
A no-load start proves the engine turns and the controller is alive, but it proves nothing about whether the set can carry rated load for the duration an outage demands. Only a load test confirms real capacity.
Low-load running keeps combustion temperatures low, so unburned fuel condenses in the exhaust and cylinders as wet, oily deposits that foul injectors and glaze liners. A load bank test burns these deposits off.
Annual testing is recommended for standby sets. Critical sites such as hospitals and data centres often test semi-annually, and AGP records the next due date in the written report.
Voltage, frequency and recovery at each load step, exhaust and temperature observations, any defects found, and a recommendation for the next test date. It is suitable for insurer and auditor review.
Yes. We inspect the set first to ensure it is safe to test, then connect the load bank and report against the nameplate rating regardless of where the set was purchased.
Book Load Testing
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