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Power Requirement Calculator :

Electrical Form

Converting kW to kVA :

Converting KVA to kW :

Converting kW to kVA

Converting KVA to kW :

Converting kVA to kW

What size genset?

Is needed to start a 3 phase electric motor Direct on Line (DOL) start?

Converting kW to HP :

Is

What size genset
Converting kW to HP

kVa/kW Amperage Chart :

This chart estimates the output amperage of a generator based on the operating power and voltage. Please note that this table is intended to be used as an estimate of how many amps a generator outputs during operation and is not an exact representation due to various factors that can increase or decrease this value.

kVa kW 208V 220V 240V 380V 400V 440V 450V 480V 600V 2400V 3300V 4160V
8
6.3
17.5
16.5
15.2
9.6
9.1
8.3
8.1
7.6
6.1
9.4
7.5
26.1
24.7
22.6
14.3
13.6
12.3
12
11.3
9.1
12.5
10
34.7
33
30.1
19.2
18.2
16.6
16.2
15.1
12
18.7
15
52
49.5
45
28.8
27.3
24.9
24.4
22.5
18
25
20
69.5
66
60.2
38.4
36.4
33.2
30.1
24
6
4.4
3.5
31.3
25
87
82.5
75.5
48
45.5
41.5
40.5
37.8
30
7.5
5.5
4.4
37.5
30
104
99
90.3
57.6
54.6
49.8
48.7
45.2
36
9.1
6.6
5.2
50
40
139
132
120
77
73
66.5
65
60
48
12.1
8.8
7
62.5
50
173
165
152
96
91
83
81
76
61
15.1
10.9
8.7
75
60
208
198
181
115
109
99.6
97.5
91
72
18.1
13.1
10.5
93.8
75
261
247
226
143
136
123
120
113
90
22.6
16.4
13
100
80
278
264
240
154
146
133
130
120
96
21.1
17.6
13.9

Approximate Diesel Fuel Consumption Chart

This chart approximates the fuel consumption of a diesel generator based on the size of the generator and the load at which the generator is operating at. Please note that this table is intended to be used as an estimate of how much fuel a generator uses during operation and is not an exact representation due to various factors that can increase or decrease the amount of fuel consumed.
Generator Size (kW) 1/4 Load (gal/hr) 1/2 Load (gal/hr) 3/4 Load (gal/hr) Full Load (gal/hr)
20
0.6
0.9
1.3
1.6
30
1.3
1.8
2.4
2.9
40
1.6
2.3
3.2
4.0
60
1.8
2.9
3.8
4.8
75
2.4
3.4
4.6
6.1
100
2.6
4.1
5.8
7.4
125
3.1
5.0
7.1
9.1
135
3.3
5.4
7.6
9.8
150
3.6
5.9
8.4
10.9
175
4.1
6.8
9.7
12.7
200
4.7
7.7
11.0
14.4
230
5.3
8.8
12.5
16.6

Formula Chart

Standard Electrical Formulas Used for Power Consumption Calculations

TO DETERMINE

SINGLE-PHASE

THREE-PHASE

DIRECT CURRENT

  • KVA

I x E
1000

I x E x 1.73
1000

——–
  • Kilowatts

I x E x PF
1000

I x E x 1.73 x PF
1000

I x E
1000

  • Horsepower

I x E x %EFF x PF
746

I x E x 1.732 x %EFF x PF
746

I x E x %EFF
746

  • Amperes (when HP is known)

HP x 746    
E x %EFF x PF

 HP x 746         
1.73 x E x %EFF x PF

HP x 746
E x %EFF

  • Amperes (when kW is known)

KW x 1000
E x PF

KW x 1000
1.73 x E x PF

KW x 1000
E

  • Amperes (when KVA is known)

KVA x 1000
E

KVA x 1000
1.73 x E

——–

Sizing a Generator :
How to Determine the Right Size for Your Needs

Choosing the right generator is a critical decision that impacts performance, reliability, and longevity. Whether you're looking for a prime power or standby generator, selecting an undersized unit can lead to system failures, equipment damage, and inefficiencies. Conversely, an oversized generator can lead to unnecessary costs. Understanding your power requirements is essential to making an informed decision.

Generator Manufacturers

Understanding Generator Sizes

Generators come in a wide range of sizes, from small, portable units for home and recreational use to large industrial generators capable of powering entire facilities. Here’s a general breakdown:
  • Residential & Small Business Use: 5kW – 50kW
  • Industrial Applications: 50kW – 3MW+
Smaller, portable generators are suitable for homes, RVs, and small offices, while larger businesses, data centers, and industrial facilities require high-capacity generators for continuous and emergency power needs.

How to Determine
the Right Generator Size

Although consulting a certified electrician is highly recommended, the following steps provide a solid starting point:

Identify Your Power Requirements

Before purchasing a generator, determine the power demand by:

  • Listing all the equipment and appliances you need to power
  • Identifying the starting and running wattage of each item
  • Calculating total power needs in kW or kVA
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