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Generator Questions

  1. How do I know what size generator I need?
  2. What are some common kW ratings for home electrical devices?
  3. What are the fuels generator use
  4. How many types of generators systems are there
  5. What's the difference in the types of generators systems

 

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How do I know what generator I need.

 

Generator sizing depends upon the amount of electrical usage you need during a power outage generator are rated in the #  kW's they can supply 1 kW is equal to 1000watts or to  put this practically this is the power you would need to light 10 100watt bulbs

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What are some common wattage ratings for home electrical devices?

 

Application Chart for Determining Electrical Load for Generator Remember  1 kW = 1000 watts    2 kW = 2000 watts  and so on The formula for finding wattage is:  Volts x Amps = Watts Example: an appliance nameplate states 3 amps at 120 volts. 3 amps x 120 volts = 360 watts Typical Electrical Appliance Wattage's

Application / Equipment Running/Rated 
Watts
Starting/Surge 
Watts
Light Bulb (100w) 100 100
Radio AM/FM 50-200 50-200
Radio, CB 50 50
Fan 200 600
Television 300-400 300-400
Microwave Oven 700 1000
Air Conditioner (12,000 BTU) 3250 5000
Furnace Fan (1/3 hp blower motor) 600 1800
Vacuum cleaner 600 750
Sump pump (1/3 hp) 700 2100
Refrigerator/freezer 800 2400
Deep Freezer 500 1500
Circular saw 1000-2500 2300-4600
Circular saw 6" 800 1000
Floodlight 1000 1000
Drill 1/2" Electric 1000 1250
Toaster 1200 1200
Coffee maker 1200 1200
Skillet 1200 1200
Chain saw 14" Electric 1200 1500
Water well pump (1/2 hp) 1000 3000
Hot plate/range (per burner) 1500 1500
Table saw 10" 2000 6000
Water heater (storage type) 5000 5000
12V DC Battery Charger 120 120

Electric Motor Wattage Usage Electric motors present a special problem. They require up to three times their rated wattage to start. Example: an electric motor name plate states 5 amps at 120 volts, 5 amps x 120 volts = 600 watts. Multiply this by 3. This will show the starting watts needed. 600 watts x 3 = 1800 watts to start. Some motor name plates will show starting watts higher in some case 9 times higher, check the name plate.  

******** ********                 Approximate Starting Watts *   

* - Always use starting watts, not running watts, when figuring correct electrical load

Motor 
HP 
Rating
Approximate 
Running 
Watts
Universal 
Motors 
(small appliances)
Repulsion 
Induction 
Motors
Capacitor 
Motors
Split 
Phase 
Motor
1/8 275 400 600 850 1200
1/4 400 500 850 1050 1700
1/3 450 600 975 1350 1950
1/2 600 750 1300 1800 2600
3/4 850 1000 1900 2600 x
1 1000 1250 2300 3000 x
1-1/2 1600 1750 3200 4200 x
2 2000 2350 3900 5100 x
3 3000 x 5200 6800 x

* - Always use starting watts, not running watts, when figuring correct electrical load x - Motors of higher horse power are not generally used

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What are the fuels that generators use.

The 4 fuels are gasoline, diesel,/ and  propane & natural gas which are the preferred fuels for automatic systems & diesel for all portables

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How many types of generators systems are there

There are 3 main types

bulletPortable with manual start bulletPortable with electric start bulletAutomatic Standby Generators

Note: Portable Type units require

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What's the difference in the types of generators systems

bulletPortable with manual start you need to move to predetermined location pull star like a lawn mower and plug the generator power cord into a Cutler Hammer panel  that Pepe Electric would install that would isolate the circuits that you feel you need in the event of a power failure. bulletPortables with electric start same as above but has a key switch like your car to start the generator. bulletAutomatic Standby Generators differ from above because you need not be home at the time power failures about 15-30seconds after power fails your generator senses this and automatically transfers power into a generator panel that Pepe Electric would install that would isolate the circuits that you feel you would need in the event of a power failure.
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Joseph Pepe Sr.
Copyright [Pepe Electric L.L.C]. All rights reserved.
Revised: September 30, 2010.

 

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