Engine KW Generator KVA

Brake Kilo Watt Electrical Kilo watt

Synchronous AC Generator

Based on ISO 8528-1 VS CAT it self

ISO rating

LTPLimited time running power

COPContinuous operating power

PRPPrime running power

CAT rating

Standby

Continuous

Prime

StandbyOutput available with varying load for the duration of the interruption for the normal power source

PrimeOutput available with varying load for an unlimited time

Continuous Output available without varying load for an unlimited time

Prime + 10 %Output available with varying load for the duration of theinterruption for the normal power source

CAT rating definitions

StandbyOutput available with varying load for the duration of the interruption for the normal power source

PrimeOutput available with varying load for an unlimited time

Continuous Output available without varying load for an unlimited time

Prime + 10 %Output available with varying load for the duration of theinterruption for the normal power source

CAT rating definitions

StandbyTypical load factor 60 % or lessTypical hours per year 100 hoursTypical peak demand 80 % of standby rated ekW with 100 %

of rating available for the duration of anemergency outage

Typical application Building services standby and enclosedor sheltered environment

Standby rating definitions

Prime + 10 %Typical load factor 60 % or lessTypical hours per year Less than 500 hoursTypical load demand 80 % of rated ekW with 100 % of rating

available for duration of an emergencyoutage

Typical application Uncovered standby, rental, power moduleUnreliable utility

Prime + 10 % rating definitions

Prime rating definitionsPrimeTypical load factor 60 % to 70 %Typical hours per year No limitTypical peak demand 100 % of prime rating used occasionallyTypical application Industrial, pumping, construction, peak

saving or cogeneration

Continuous rating definitionsContinuousTypical load factor 70 % to 100 %Typical hours per year No limitTypical peak demand 100 % of continuous rating used 100 %

of the timeTypical application Base load, utility, cogeneration, parallel

operation

Load factor = % of time X % of load

% of time = --------------------------Time at specific load

Total operating time

% of load = -----------------Specific load

Rated load

LOAD FACTOR

LOAD FACTOR

Sample Genset rated at 550 KWRuns two hours a weekDuring two hours it runs at 400 KW for 1.5 hours

% of load = ------------400 Kw550 Kw

= 0.73 %

% of time = ----------------90 minutes

120 minutes= 0.75 %

Load factor = 0.73 X 0.75 = 54.75 %

Rating

Generator name plate

CAT generator rating is based on temperature riseRefer to NEMA ( National Electric Manufactures Association )And IEC ( International Electro-technical Commission )

Generator class Temp. rise Gen-set rating

F 80 ContinuousH - -

F 105 PrimeH 125 Prime

F 130 StandbyH 150 Standby

How to define total temperature limit ?

Temperature rise + 40oC + 10oC

As table shownAmbient temp

Hot spot margin

Sample:Prime power F class has 105OC riseThe total temp rise is 155OC

Field common operating rpm1000 rpm1200 rpm1500 rpm1800 rpm

Basic generator

Three phase generation