What is the difference between ESP and PRP ratings?
ESP is emergency standby power with limited annual running hours. PRP is prime power at variable load for unlimited hours. ISO 8528-1 defines the permitted load factor and overload for each.
Products we supply
Generator Sets & Standby Power
Diesel, gas, gasoline, marine and solar generator sets with transfer and synchronisation panels, sized for the load that starts, not only the load that runs.
01Overview
Supply and engineering from one team
Powersense supplies diesel generator sets from 80 to 1,385 kVA, gasoline sets from 2.7 to 16 kVA, natural-gas sets from 8 to 17 kVA, marine generators from 8 to 31 kVA and mobile solar PV generators from 100 to 3,000 W, and engineers sizing, changeover and synchronisation.
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02Scope and process
Engineering scope and deliverables
- 01
Duty definition
Standby (ESP) or prime (PRP) duty, running hours and load factor are defined under ISO 8528-1.
DeliverableDuty statement - 02
Load analysis and sizing
Critical loads, the starting current of the largest motor, voltage dip and step-load acceptance determine the kVA rating.
DeliverableGenerator sizing calculation - 03
Fuel, ventilation and exhaust
Fuel storage, combustion and cooling air, exhaust routing, noise and emission requirements are defined for the room or enclosure.
DeliverablePlant-room requirements - 04
Transfer and synchronisation
An automatic transfer switch or synchronisation panel provides changeover and paralleling, with interlocks against back-feed to the grid.
DeliverablePanel drawings, control sequence - 05
Protection and earthing
Generator protection, the neutral earthing arrangement and coordination with downstream devices are checked against the generator's fault current (IEC 60364-5-55).
DeliverableProtection settings, earthing design - 06
Load test and commissioning
Load-bank and transfer tests are carried out at commissioning, and remote monitoring is set up where required.
DeliverableTest and commissioning report
03Standards
International standards applied
These standards form the technical basis for design and equipment selection. The exact set is confirmed for each project against the national regulations in force.
- ISO 8528-1Reciprocating internal combustion engine driven generating sets: application, ratings and performance.
- ISO 8528-5Reciprocating internal combustion engine driven generating sets: generating sets.
- ISO 3046-1Reciprocating internal combustion engines: performance, declarations of power and consumption.
- IEC 60034-1Rotating electrical machines: rating and performance.
- IEC 60364-5-55Other equipment, including low-voltage generating sets (clause 551): selection and erection.
- IEC 61439-1Low-voltage switchgear and controlgear assemblies: general rules and design verification.
04Products
Products we supply
- Diesel generator sets, 80 to 1,385 kVA
- Gasoline generators, 2.7 to 16 kVA
- Natural-gas generators, 8 to 17 kVA
- Marine generators, 8 to 31 kVA
- Mobile solar PV generators, 100 to 3,000 W
- Transfer and synchronisation panels, remote monitoring
05Project types
Typical project types
- Hospitals and hotels
- Industrial plants
- Data centres
- Commercial buildings
- Marine and yacht installations
- Remote and temporary sites
06Technical notes
Technical notes and FAQ
Why does the largest motor matter in sizing?
Its starting current causes a voltage and frequency dip. The set must start the largest motor while other loads are running, so the starting method (direct-on-line, soft starter or drive) is part of the sizing.
07Keep exploring
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