Frequently Asked Questions

The correct diesel generator size is based on the facility's running load, starting load, motor loads, UPS systems, load steps, required redundancy, and future expansion.

Simply adding the nameplate ratings of connected equipment may not provide an accurate result. Large motors, pumps, compressors, and transformers can create short-duration starting demands that are much higher than their normal operating loads.

A detailed load study should confirm the required kW, kVA, voltage, frequency, operating rating, and expected load profile before the final generator configuration is selected.

Data center generator sizing depends on the critical IT load, cooling systems, UPS capacity, mechanical equipment, starting currents, required runtime, and redundancy strategy.

The design may use N, N+1, 2N, or distributed redundant architecture. The selected capacity should support the required critical load while allowing for maintenance, future expansion, and step-load conditions.

A coordinated electrical load study should be completed before the final number and capacity of generator sets are selected.

The appropriate generator capacity depends on the actual design load, required reserve capacity, motor starting demand, redundancy target, and expected future growth.

A larger generator is not always the best choice. Oversizing can lead to prolonged low-load operation, while undersizing may cause voltage or frequency instability during major load steps.

For critical facilities, it may be better to compare one large unit with multiple smaller generators operating in parallel before making the final selection.

Standby rating is generally used for emergency backup when utility power is normally available. Prime rating is intended for extended operation with a variable load where utility power is unavailable or unreliable. Continuous rating is intended for long-duration operation at a relatively constant load.

The applicable rating should always be confirmed using the engine and generator manufacturer's published rating definitions for the intended operating profile.

Industrial generators can be configured for low- and medium-voltage systems. Common project voltages may include 208 V, 480 V, 600 V, 4.16 kV, 13.8 kV, and other application-specific levels.

The correct voltage depends on the facility distribution system, connected equipment, transformer arrangement, cable requirements, generator capacity, and applicable electrical standards.

A 3 MW generator may be configured for 480 V, but the final design must account for the resulting current, alternator capability, switchgear rating, cable quantity, voltage drop, protection, and site distribution arrangement.

At multi-megawatt power levels, medium-voltage generation may also be considered to reduce current and simplify power distribution. The best option depends on the project layout, existing electrical system, and total installed cost.

Kilowatts, or kW, represent real power available to perform useful work. Kilovolt-amperes, or kVA, represent apparent power and include both real and reactive power.

The relationship is commonly expressed as kW = kVA × power factor. For example, a 1,250 kVA generator at a 0.8 power factor provides 1,000 kW of real power.

Generator sizing should consider both kW and kVA because motors, transformers, UPS systems, and other loads can affect power factor and reactive power demand.

One 3 MW generator may offer a simpler system with fewer controls and less equipment. Three 1 MW generators may provide greater redundancy, staged capacity, improved maintenance flexibility, and better support for variable load conditions.

The comparison should consider first cost, available space, fuel use, switchgear, synchronization, maintenance strategy, expansion plans, and the consequences of losing one generator.

Critical facilities often evaluate both options through a reliability and lifecycle-cost study before selecting the final architecture.

N+1 redundancy means the system includes the number of generators required to support the design load, plus one additional generator.

The extra unit can allow the system to continue supporting critical loads when one generator is unavailable because of maintenance, testing, or an equipment fault.

A complete N+1 design must also consider switchgear, controls, fuel, cooling, auxiliaries, and other shared components that could create a single point of failure.

Yes. Multiple generator sets can operate in parallel to provide more capacity, load sharing, redundancy, maintenance flexibility, and future expansion.

A parallel system requires compatible controls, synchronization, protection, load-sharing logic, switchgear, and coordinated system engineering.

The control strategy should also define generator sequencing, minimum loading, load steps, failure response, and operation during testing or maintenance.

A UPS provides immediate power to critical loads when utility power fails. The standby generator then starts, reaches stable voltage and frequency, and supplies the facility through the transfer or paralleling system.

The generator must be sized for the UPS input characteristics, battery-recharge load, harmonic content, power factor, and potential load steps. Coordination between the UPS, generator controls, and switchgear is important for stable operation.

Fuel tank capacity should be calculated from the generator's model-specific fuel-consumption rate, expected operating load, required runtime, usable tank volume, and reserve margin.

The calculation should also account for fuel-return arrangements, minimum operating level, delivery access, local code requirements, environmental containment, and fuel-quality management.

Manufacturer data at 25%, 50%, 75%, and 100% load should be reviewed rather than relying on a generic fuel-consumption estimate.

A generator intended for cold Canadian climates should be configured for the expected minimum temperature, snow, wind, moisture, and site exposure.

Cold-weather provisions may include engine block heaters, battery heaters, space heaters, winter-grade fluids, suitable ventilation, weatherproof enclosures, snow protection, and appropriately rated starting batteries.

The final winterization package should be selected for the specific generator model, fuel system, project location, and required starting performance.

An automatic transfer switch, or ATS, typically transfers a load between utility power and a standby generator. Generator paralleling switchgear controls and connects multiple generator sets so they can synchronize and share load.

An ATS is commonly used in a simpler single-generator standby system. Paralleling switchgear is used when the project requires multiple generators, redundancy, staged capacity, load sharing, or complex operating sequences.

Lead time depends on generator capacity, engine and alternator availability, voltage, enclosure type, control system, emissions requirements, testing, transportation, and project customization.

In-stock units may be available sooner, while customized multi-megawatt packages normally require additional engineering, manufacturing, testing, and delivery time.

Providing the required capacity, voltage, fuel type, project location, specifications, and target delivery date allows ETAC Power to confirm current availability and an estimated project schedule.

Helpful project information includes:

• Required generator output in kW, kVA, or MW
• Voltage, phase, and frequency
• Standby, prime, or continuous rating
• Fuel preference
• Indoor or outdoor installation
• Enclosure, sound, and weather requirements
• Project location and site conditions
• Required delivery date
• Redundancy or paralleling requirements
• Applicable specifications, single-line diagrams, or drawings