Sales FAQs
Q: What size Power Tech Generator do I need?
A: Power requirements must be determined to properly size your generator. Power Tech is providing some steps to assist you in approximating the size generator for your power needs. Please keep in mind that unless you are qualified, you should use a certified electrician to determine your power needs. If you have any questions, please contact us.
STEPS TO DETERMINE POWER TECH GENERATOR REQUIREMENTS
1. Determine your need. Do you want the generator to operate part or all of your electrical needs?
2.Identify the appliances and/or tools the generator will need to power.
3. Determine the wattage for each appliance and tool you plan to use frequently. The chart below will help you determine your need.
4. Total the wattage for appliances and tools you frequently use.
5. Identify motor and pump requirements. Use the motor and pump charts provided below.
6. Calculate and total the wattage for the motors and pumps used. Always use starting watts, not running watts, when determining the correct electrical load requirements.
7. Total the wattage of the appliances, tools, motors, and pumps.
8. Convert watts into kilowatts by dividing the watts in step 4 to determine the generator size required. Please note that it is suggested, to size the generator 20-25% over the size you determine your needs to be. This will allow room for future growth. If you determine that you will need a 15 kW generator then it is advisable to purchase a 17.5 kW generator to accommodate future expansion.
COMMON WATTAGES:
| Item |
Running Watts |
Starting Surge |
| 100 watt light bulb |
100 |
100 |
| Radio/Stereo |
50-200 |
50-200 |
| Radio CB |
50 |
50 |
| Fan |
200 |
200 |
| Television |
300-400 |
300-400 |
| Microwave |
700 |
1000 |
| Air Conditioner (varies) |
3250 |
5000 |
| Furnace fan (1/3 HP) |
600 |
1800 |
| Vacuum cleaner |
600 |
750 |
| Sump pump (1/3 HP) |
700 |
2100 |
| Refrigerator/ Freezer |
800 |
2400 |
| Freezer |
500 |
1500 |
| 6" circular saw |
800 |
1000 |
| Floodlight |
1000 |
1000 |
| 1/2" electric drill |
1000 |
1000 |
| Toaster |
1200 |
1200 |
| Coffee maker |
1200 |
1200 |
| Electric skillet |
1200 |
1200 |
| Hair dryer |
1500 |
1500 |
| 1/2 HP water well pump |
1000 |
3000 |
| Hot plate |
1500 |
1500 |
| Electric range |
10000 |
10000 |
| 10" table saw |
2000 |
6000 |
| Hot water heater |
5000 |
5000 |
ELECTRIC MOTOR WATTAGE REQUIREMENTS
Electrical motors present special electrical startup considerations. They can require up to three times
their rated running wattage to start. Motor nomenclature plates generally will show starting watts, some
as high as nine times the running wattage. Check the nomenclature to be sure. Be certain to use the
starting watts when figuring the correct electrical load requirements.
Motor Rating HP |
Approximate Running Watts |
Universal Motors Small Appliance |
Reduction Induction Motors |
Capacitor Motors |
1/8 |
275 |
400 |
600 |
850 |
1/4 |
400 |
500 |
850 |
1050 |
1/3 |
450 |
600 |
975 |
1350 |
1/2 |
600 |
750 |
1300 |
1800 |
3/4 |
850 |
1000 |
1900 |
2600 |
1 |
1000 |
1250 |
2300 |
3000 |
1 1/2 |
1600 |
1750 |
3200 |
4200 |
2 |
2000 |
2350 |
3900 |
5100 |
3 |
3000 |
3550 |
5200 |
6800 |
WELL PUMP KW REQUIREMENTS
Pump HP Rating |
Generator |
|
Min. KW |
Min. KVA |
1/3 |
1.5 |
1.9 |
1/2 |
2.0 |
2.5 |
3/4 |
3.0 |
3.8 |
1 |
4.0 |
5.0 |
1 1/2 |
5.0 |
6.25 |
2 |
7.5 |
9.4 |
3 |
10.0 |
12.5 |
5 |
15.0 |
18.75 |
7 1/2 |
20.0 |
25.0 |
10 |
30.0 |
37.5 |
NOTE: It is recommended that the Power Tech Generator be started before the pump motor is turned on.
- Power Tech Generators are externally regulated. Generators must be sized to deliver at least 65% of the rated voltage during motor starting to ensure adequate motor starting torque.
- To convert KW into watts multiply KW (x) 1000.
Q: How do I convert AMPS to kW or KVA?
A: Use the following conversion charts:
3 PHASE AMPERES - 80% POWER FACTOR
KVA |
KW |
208V |
220V |
240V |
380V |
416V |
440V |
480V |
6.3 |
5 |
17.5 |
16.5 |
15.2 |
9.6 |
8.6 |
8.3 |
7.6 |
9.4 |
7.5 |
26.1 |
24.7 |
22.6 |
14.3 |
13 |
12.3 |
11.3 |
12.5 |
10 |
34.7 |
33 |
30.1 |
19.2 |
17.3 |
16.6 |
15.1 |
18.7 |
15 |
52 |
49.5 |
45 |
28.8 |
26 |
24.9 |
22.5 |
25 |
20 |
69.5 |
66 |
60.2 |
38.4 |
34.7 |
33.2 |
30.1 |
31.3 |
25 |
87 |
82.5 |
75.5 |
48 |
43.4 |
41.5 |
37.8 |
37.5 |
30 |
104 |
99 |
90.3 |
57.6 |
52 |
49.8 |
45.2 |
45 |
36 |
125 |
118 |
108 |
68 |
62.5 |
59 |
54 |
56.3 |
45 |
156 |
147 |
135 |
85.5 |
78 |
74 |
68 |
62.5 |
50 |
173 |
165 |
152 |
96 |
86 |
83 |
76 |
75 |
60 |
208 |
198 |
181 |
115 |
104 |
99.6 |
91 |
93.8 |
75 |
261 |
247 |
226 |
143 |
130 |
123 |
113 |
100 |
80 |
278 |
264 |
240 |
154 |
139 |
133 |
120 |
125 |
100 |
347 |
330 |
301 |
192 |
173 |
166 |
150 |
156 |
125 |
433 |
413 |
375 |
240 |
217 |
208 |
188 |
187 |
150 |
520 |
495 |
450 |
288 |
260 |
249 |
225 |
219 |
175 |
608 |
577 |
527 |
335 |
304 |
289 |
264 |
250 |
200 |
694 |
660 |
601 |
384 |
347 |
332 |
301 |
312 |
250 |
866 |
825 |
751 |
480 |
434 |
415 |
376 |
375 |
300 |
1040 |
990 |
903 |
576 |
521 |
498 |
451 |
438 |
350 |
1220 |
1155 |
1053 |
672 |
607 |
581 |
527 |
500 |
400 |
1390 |
1320 |
1203 |
770 |
694 |
665 |
602 |
625 |
500 |
1735 |
1650 |
1504 |
960 |
868 |
830 |
752 |
750 |
600 |
2080 |
1970 |
1803 |
1141 |
1042 |
985 |
903 |
812 |
650 |
2257 |
2135 |
1958 |
1236 |
1129 |
1067 |
978 |
937 |
750 |
2605 |
2463 |
2257 |
1426 |
1303 |
1232 |
1128 |
SINGLE PHASE AMPERES
KVA |
120\240 |
5 |
20.8 |
8 |
33.3 |
10 |
41.6 |
15 |
62.5 |
20 |
83.3 |
25 |
104 |
30 |
125 |
35 |
145 |
40 |
166 |
45 |
187 |
50 |
208 |
60 |
250 |
65 |
270 |
76 |
312 |
80 |
333 |
100 |
416 |
125 |
520 |
150 |
625 |
175 |
729 |
200 |
833 |
225 |
937 |
230 |
958 |
260 |
1041 |
275 |
1145 |
300 |
1250 |
350 |
1458 |
400 |
1666 |
425 |
1770 |
450 |
1876 |
500 |
2083 |
NEMA CODES FOR STARTING KVA/hp THREE PHASE MOTORS
CODE |
STARTING KVA/HP |
TYPICAL SIZE RANGE |
CODE |
STARTING KVA/HP |
TYPICAL RANGE |
A |
0 - 3.15 |
- |
L |
9.0 -10.0 |
1 HP |
B |
3.15 - 3.55 |
- |
M |
10.0 - 11.2 |
Less than 1 HP |
C |
3.55 - 4.0 |
- |
N |
11.2 - 12.5 |
- |
D |
4.0 - 4.5 |
- |
P |
12.5 - 14.0 |
- |
E |
4.5 - 5.0 |
- |
R |
14.0 - 16.0 |
- |
F |
5.0 -5.6 |
15 HP and up |
S |
16.0 - 18.0 |
- |
G |
5.6 - 6.3 |
10 HP |
T |
18.0 - 20.0 |
- |
H |
6.3 - 7.1 |
7.5 and 5 HP |
U |
20.0 - 22.4 |
- |
J |
7.1 - 8.0 |
3 HP |
V |
22.4 and up |
- |
K |
8.0 - 9.0 |
2 and 1-1/2 |
|
|
|
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 |
|
|
