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Power calculator

These calculators will assist you in determining what size generator you may require or how to convert one unit of electricity to another.

They calculate:

Amperes when kVA is known
Converting kVA to kW
Converting kW to kVA
Converting kW to HP
kVA Required to run motors

Guide to units:

HP = Horsepower
kW = Kilo Watts
kVA = Kilo Volt Amps
I = Ampere or Current
V = Volts
PF = Power Factor

Sizing Data - Domestic Power Consumption - click here

Calculating Ampere (I), given kVA

Phase
1, 2, 3
Generator
kVA
Volts
Required
= Ampere
I


Converting kVA to kW
kVA = kW
Converting kW to kVA
kW = kVA


Converting kW to HP

kW

=

HP


What size genset is needed to start a 3 phase electric motor Direct on Line (DOL) start
HP of
Motor
= Generator
kVA Required


Generator Size to Start Motors

Instructions: You only need to fill in the columns coloured in orange.
Fill in the HP of the motor(s) in their starting squence, select the start method (Direct On Line or Star Delta) and press Evaluate. The required generator size will then be displayed at the bottom.

3 Phase (415 volt @ 50Hz)
1 Phase (240 volt @ 50Hz)

Starting
Sequence

Motor HP

Start Method
DOL / StarDelta

Run
Variable

Phase
Current

Starting
Value

Total Run
Current

Total Start
Current

1 /
2 /
3 /
4 /
5 /
6 /
Generator Size for Starting with: kVA*
Generator Size for Running with: kVA*
Generator Size Recommended: kVA*

* Please NOTE the above calculations are an estimate only because other factors such as site conditions, motor efficiencies and iron losses are not taken into consideration.


Domestic Power Guide

Appliance

Rated Watts

Rated kVA

Rated kVA

Appliance

Gene to run appliance

Gene to start appliance

Air Conditioner (Evap model)

275-1000

0.34-1.25

1.36-5

Air Conditioner (Rev cycle)

200-2500

0.25-3.13

1-12.5

Clothes Dryer

2400

3

3

Coffee Percolator

550

0.69

0.69

Can Opener

100

0.13

0.52

Deep Freezer

500

0.63

2.52

Disposal Unit

650

0.81

3.24

Dishwasher

1000-3000

1.25-3.75

1.25-3.75

Domestic Water Pumps

275-1000

0.34-1.25

1.36-5

Exhaust Fan

40

0.05

0.2

Food Processor

500

0.63

2.52

Fry pan

1400

1.75

1.75

Hair Dryer

1500

1.88

1.88

Hot water Service

2500-3000

3.13-3.75

3-13-3.75

Iron

800-1500

1-1.88

1-1.88

Kettle or jug

1600-3000

2-3.75

2-3.75

Lights

25-200

0.03-0.25

0.03-0.25

Microwave

1500

1.88

1.88

Oven

4000-8000

5-10

5-10

Radio

60

0.08

0.08

Radiator

1000-2500

1.25-3.13

115-3.13

Refrigerator (home)

300

0.38

1.52

Sewing Machine

60

0.08

0.32

Space Heater

2000

2-5

2.5

Television

75-200

0.09-0.25

0.09-0.25

Toaster

250-1250

0.3-1.56

0.3-1.56

Washing Machine

500-3000

0.63-3.75

2.52-15

Welder 140A

5000

6.25

8 min