Load banks, built in Pune, up to 1000 kW
Standby plant is only as good as its last test. A load bank applies a real, controlled, measurable load so the capacity written on the nameplate is the capacity you actually have.
- Maximum capacity
- Up to 1000 kW
- What it tests
- DG sets, UPS systems, inverters and battery banks
- Method
- Converts the source output to heat — a real, measurable load
- Build
- To specification against the plant being proved
And when it’s the right answer
A load bank is a device that consumes electrical power on purpose. It takes the output of the source under test and turns it into heat, which is dumped to air, so the source is made to work at a load you choose and can hold there for as long as the test needs. Nothing downstream is at risk, because the building load is not involved at all.
The reason to own one is that standby equipment fails quietly. A diesel set that only ever runs its weekly no-load exercise never reaches proper cylinder temperature, so fuel goes through unburnt and glazes the bores, and carbon builds at the turbo and in the exhaust — wet stacking, and it is the commonest way a generator that starts perfectly turns out not to be able to hold the building when the day comes. A load bank is what puts real work in front of the engine.
The same argument holds for anything with a battery behind it. A bank loses capacity from the day it is installed, and the loss is invisible until the discharge that matters. The commissioning certificate in the file records what the system did on one day, years ago, at an ambient temperature nobody wrote down. Discharging the bank against a known load is the only thing that tells you what it will do this year.
We build load banks up to 1000 kW. Above the smallest sizes this is not a catalogue item — the rating, the voltage and the way the load is stepped follow from what you are proving, so it is specified against the plant rather than picked off a list.
Two problems. The real load is rarely anywhere near the rating, so a set that passes on it has only proved it can do the easy part — and the test itself is now being run on live equipment, which means the failure you are looking for happens to a hospital ward or a production line rather than to a resistor.
A weekly off-load run proves the set starts, the battery is charged and the fuel is not stale. That is worth doing and it is not a capacity test. It also causes wet stacking rather than clearing it, which is the part that surprises people.
Hire is the right answer for a one-off commissioning. It stops being the right answer once testing is routine — a DG dealer proving every set before handover, a rental fleet checking machines between jobs, a facilities team on an annual schedule. At that point the hire invoices overtake the machine.
Where these get installed
- Commissioning a new DG set at rated output before handover
- Periodic loaded exercising of standby generators to clear wet stacking
- Proving UPS capacity and transfer behaviour under full load
- Battery bank discharge testing against the design runtime
- Verifying a machine after repair or overhaul, before it goes back on site
- Acceptance testing witnessed by a consultant or the client
Full specification
Typical values for the standard build. Every unit is configured to order — the figures on your general arrangement drawing are the ones that apply.
| Maximum capacity | Up to 1000 kW |
|---|---|
| What it tests | DG sets, UPS systems, inverters and battery banks |
| Method | Converts the source output to heat — a real, measurable load |
| Build | To specification against the plant being proved |
| Voltage and phases | Matched to the source under test — confirmed at enquiry |
| Load steps | Specified against how the test has to be staged |
| Cooling and mounting | Specified against site access and where it will stand |
| Typical use | Commissioning, post-repair verification, scheduled proving |
Sectors that buy this
Data Centres & Server Rooms
Redundancy topology, battery runtime to DG pickup, and heat rejection. At this scale the UPS is the easy part of the specification.
Hospitals & Diagnostics
The load list in a hospital is not one load. Theatres, imaging, ICU and the server room each need a different answer, and the specification has to hold up in an NABH audit.
Telecom & Networks
Telecom runs on −48 V DC and on sites nobody visits. Modular redundancy and remote telemetry are the whole specification.
Defence & Aerospace
400 Hz ground power, frequency conversion for test benches, and supplies specified against MIL-STD-704 rather than a catalogue.
Questions we get asked
Anything not covered here, call us — most of it is faster to answer on the phone.
01What is a load bank?
A load bank is equipment that draws a known, controlled load from a power source and dissipates it as heat. It exists so a generator, UPS or battery bank can be run at its rated output and measured, without connecting any real equipment to it. It produces nothing and stores nothing — consuming power under control is the entire function.
02Why not just test on the building load?
Because the building load is usually a fraction of the rating, so passing on it proves very little, and because a failure during the test then lands on live equipment. A load bank lets you hold the source at full rating for as long as the test needs, and step it up and down deliberately, with nothing important connected.
03What is wet stacking?
It is what happens to a diesel engine that spends its life on light load. The cylinders never reach working temperature, so fuel passes through unburnt and collects in the exhaust, glazing the bores and fouling the turbo. The set still starts on demand, which is what makes it deceptive — it simply cannot hold rated load any more. Loaded running is the cure and the prevention.
04Resistive or reactive — which do I need?
A resistive load bank loads the engine and the thermal side of the set at unity power factor, and for most standby diesel testing that is the test being asked for. A reactive load bank adds a lagging power factor, which is what exercises the alternator and the AVR — relevant when the real load is motor-heavy or when a specification calls for it. Tell us what you have to prove and we will confirm which build applies.
05How big a load bank do I need?
It follows from the rating you have to prove and from how the test is staged. A single block equal to the full rating is rarely what you want — a bank stepped in stages lets you bring the source up gradually, hold it, and see what happens at each level rather than only at the top. Send us the plant details and the standard you are testing to.
06How often should a generator be load tested?
The regime most contracts and insurance schedules specify is a monthly exercise run at a meaningful load plus an annual test at or near full rating. Where the building cannot supply a meaningful load, that is exactly the gap a load bank fills. Check the wording that governs your own site before designing a regime around a rule of thumb — insurers, hospital accreditation schemes and data centre standards all require this and they do not all require the same thing.
07What do you need from us to quote one?
Six things, and most people have them on the nameplate: the rating you have to prove in kW or kVA; the voltage and number of phases; the frequency; how the test has to be staged, meaning the step sizes you want to hold at; where the unit will stand and how it gets there; and whether you are testing to a written standard or an internal schedule. Send those and you get a real answer rather than a range.
Where we supply and attend
Load Bank units are built at our Pune works and delivered, installed and commissioned across the city and the industrial belt around it.
Outside these areas we contract individually against distance, and we will tell you honestly if the response time you need is not one we can hold to. All areas served
After it’s installed
We service what we build, and what everyone else builds too.