Require VA,Watts,max. amps. & power factor in order to size a backup generator

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Posted on Jan 02, 2017

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SOURCE: I am installinga 4548 inverter.

Let just wait a minute. You have an inverter that is rated at 4500 watts.
This spooky. The inverter has a three phase input/three phase output? What is
the inverter going to be used for?

Next question. What type of batteries are you using and what is the
voltage/current in series or parallel? What will be the total voltage you will
producing with the batteries? What is the total current of the batteries.

Another question? What is the voltage of the 28 amps? If it going to dump 28
amps across some batteries that rated at 12 volts and 1400 amp/hrs. For 12 volt batteries with a total of 1400 amps. What you will
need approx 14 to 14 1/2 DC and with 28 amps across the batteries for charging
these batteries. The batteries will be gone in about 1 hour. Boil all the water
out of them. When a battery starts to boil it release water with hydrogen gas
(the gas is very explosive and dangerous).

You also don't have a regulation circuit to limit the amount of current
depending on the needs of the batteries. Also, you don't have a trickle charger
to keep the batteries fully charge when the batteries are idle.

You will also need DC regulated charger that will keep the voltage 2-4 volts
above you battery voltage. Without this voltage above the batteries voltage it
will not charge those batters. Batteries need to forced to except a charge
that why voltage above the source voltage. If you can check the voltage on your
car/truck with a 12 volt system. While engine is running the voltage across the battery
will be 13.8 to 14.1 volts. Now, the current limiter is the alternator it has a
regulator built into it for stabiizing voltage and current went the batteries
require more current but it limited by alternator regulator

Now, to get more current out of the alternator the regulator will supply dc
voltage to the stator of the alternator generator more current. More dc voltage
is supplied by the regulator but the dc voltages is limit to about 24 volts.
Another limiting factor is the alternator copper windings diameter---larger
diameter more current, small diameter less current. Utilities systems use big
mega watts generators. The maxi um dc voltage for these three phase generator
would like 500 to 800dc volts for peak to peak output. There is a simpler way of
doing this.

You need to rethink everything here. Also, I can help you if you supply the
needed information.

I truly wish you luck in your electrical endeavors. GB you. stewbison

Posted on Aug 22, 2011

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SOURCE: Need to know if I

Hello Bob,

There should be absoluty no problem on that 1600 watt generator..at max when compressor just starts its drawing about 750 watts, that is the max usage when running its about 500 and on defrost its like 850 ..so on 1600 watt generator no problem

Posted on Aug 25, 2011

SOURCE: I have a kenmore refrig/freezer.

Hello,

The calulation of max wattage is going to be 750 watts at start up and be around 500 on normal running wattage after start up so a 1100 watt generator should be fine.

GENE

Posted on Sep 06, 2011

Look at rating plate on side of unit for Volts, Amps, Watts.

Volts x amps = watts.

If unit is 240Volts, then you need double-pole 240Volt breaker

If unit is 8500 watts at max power, then 8500 watts divided by 240Volts = 35 amps.

What size breaker for 35 amps?

When electricians figure load rating for breakers, they use the 80% rule.

40 amp breaker x 80% = 32 amp safe maximum load for 40 amp breaker. Use 8 gauge wire with 40 amp breaker.

50 amp breaker x 80% = 40 amp safe maximum for 50 amp breaker. I use 6 gauge wire with 50 amp breaker.

60 amp breaker x 80% = 48 amp safe maximum for 60 amp breaker. Again, use 6 gauge wire with 60 amp breaker.

How to connect wires to unit.

First of all, all outdoor HVAC units require power cut off located next to unit.

This lets the mechanic, or service tech turn power off to work on unit, even if the mechanic does not have access to main breaker box.

Next, open unit to see where wires connect.

If unit has wires, then connect both hot wires from 240 breaker to the wires inside unit. Connect bare ground wire to green ground screw.

If unit has terminals. The terminals will be labeled L1 L2. Connect each hot wire from 240Volt breaker to either one of the screw terminals. Then bare ground goes to green ground screw.

Copy following links for basic illustrations connecting wires to terminals, and to breakers, and selecting wire size.

http://waterheatertimer.org/How-to-wire-Tankless-electric-water-heater.html

Volts x amps = watts.

If unit is 240Volts, then you need double-pole 240Volt breaker

If unit is 8500 watts at max power, then 8500 watts divided by 240Volts = 35 amps.

What size breaker for 35 amps?

When electricians figure load rating for breakers, they use the 80% rule.

40 amp breaker x 80% = 32 amp safe maximum load for 40 amp breaker. Use 8 gauge wire with 40 amp breaker.

50 amp breaker x 80% = 40 amp safe maximum for 50 amp breaker. I use 6 gauge wire with 50 amp breaker.

60 amp breaker x 80% = 48 amp safe maximum for 60 amp breaker. Again, use 6 gauge wire with 60 amp breaker.

How to connect wires to unit.

First of all, all outdoor HVAC units require power cut off located next to unit.

This lets the mechanic, or service tech turn power off to work on unit, even if the mechanic does not have access to main breaker box.

Next, open unit to see where wires connect.

If unit has wires, then connect both hot wires from 240 breaker to the wires inside unit. Connect bare ground wire to green ground screw.

If unit has terminals. The terminals will be labeled L1 L2. Connect each hot wire from 240Volt breaker to either one of the screw terminals. Then bare ground goes to green ground screw.

Copy following links for basic illustrations connecting wires to terminals, and to breakers, and selecting wire size.

http://waterheatertimer.org/How-to-wire-Tankless-electric-water-heater.html

Jul 21, 2012 | Rheem R-410A Complete Split System Heat...

With voltage step down power supplies, output power is more important than data plate output V (volts). V times output A (data-plate amps) equals output Watts (or VA) under normal load. If the voltages are close and the output watts (VA) are very close (one or two watts) you are in luck as long as the connector is same size; AND THE POLARITY (+ & -) IS THE SAME for the old and replacement unit!

Jan 17, 2012 | Fujitsu LifeBook P7120 Laptop AC Power...

Steve,

The microwave alone shouldn't cause a problem for the generator as even the most powerful models run about 1200 watts or about 10 amps. An air conditioner on the other hand, can draw considerably more power to run depending on BTU size; 15 amps and up is not uncommon (and even twice as much as that though only briefly when starting).

If these were the only things connected and on, the generator should be able to handle them - again depending on the BTU size of the AC unit. Generators state their capacity in Watts, but must of the devices we connect are in Amps. Calculating Watts in an AC circuit is complicated, but pretty close to the much easier Watts in a DC circuit for most residential settings. Here's how it's done:

Watts = volts x amps. Pretty simple stuff. Your generator is rated at 5500 watts. The microwave is say, 120 volts / 10 amps - which equals 1200 watts. The generator has 4300 capacity available now. Suppose your air conditioner is rated at 120 volts / 15 amps - which equals 1800 watts. 4300watts - 1800watts = 2400watts capacity is left. But, the starting current for the AC is as much as 25 amps for a few seconds (and once started drops back to 15 amps) - which means there's only 1200 watts capacity left. Add up the rest of the appliances you're running at the same time (TV set, Cable / Satellite box, stereo, toaster, lights, computer, etc.- you get the idea), and you can see how you might have exceeded the 5500 watts capacity of the generator for a few seconds. It's at these times that your hear / see the generator speed falter and sputter, lights dim, etc.. If this is happening a lot, you may need a larger or additional generator.

I hope this helps and good luck!

The microwave alone shouldn't cause a problem for the generator as even the most powerful models run about 1200 watts or about 10 amps. An air conditioner on the other hand, can draw considerably more power to run depending on BTU size; 15 amps and up is not uncommon (and even twice as much as that though only briefly when starting).

If these were the only things connected and on, the generator should be able to handle them - again depending on the BTU size of the AC unit. Generators state their capacity in Watts, but must of the devices we connect are in Amps. Calculating Watts in an AC circuit is complicated, but pretty close to the much easier Watts in a DC circuit for most residential settings. Here's how it's done:

Watts = volts x amps. Pretty simple stuff. Your generator is rated at 5500 watts. The microwave is say, 120 volts / 10 amps - which equals 1200 watts. The generator has 4300 capacity available now. Suppose your air conditioner is rated at 120 volts / 15 amps - which equals 1800 watts. 4300watts - 1800watts = 2400watts capacity is left. But, the starting current for the AC is as much as 25 amps for a few seconds (and once started drops back to 15 amps) - which means there's only 1200 watts capacity left. Add up the rest of the appliances you're running at the same time (TV set, Cable / Satellite box, stereo, toaster, lights, computer, etc.- you get the idea), and you can see how you might have exceeded the 5500 watts capacity of the generator for a few seconds. It's at these times that your hear / see the generator speed falter and sputter, lights dim, etc.. If this is happening a lot, you may need a larger or additional generator.

I hope this helps and good luck!

Dec 25, 2011 | Watts Onan Portable Generator - 5000 ,...

What type of load (electrical) was hooked up to this generation?? If the surge
voltage and current was exceeded above the generator maximum for any length of
time. There problems, it could be the regulator, insulation burnt off the
windings.

I am taking a guess here. Now, 7100 Watts is it typical surge wattage. This mean that the generator will deliver 7100 Watt (voltage times current) this is know as the power factor. The actual operating load would be 6800 Watts and I would even operator the generator at its peak wattage. Something in the neighborhood of 10--15% less the peak wattage. Therefore a good positive theatrical Wattage would be 5800 to 6350 operating wattage. Then this generator would run all day.

Just remember Ohm's Law. Current plays a big factor in loading of a generator while the operation voltage is at 120 AC Volts. Example: electric motor; Now electric motor when starting will pull three time its operation current. Operating current for a 1/2 HP AC motor is 6 amperes but start this electric motor will require 18 amperes. This is one reason why they starting capacitors on smaller electric motors. Larger three phase electric motor can literal stop a generator cold...in its tracks. It put such a large demand on the generator it stops the engine powering the generator. I have seen crankshaft break because the generator could handle the heavy current load.

Remember, any time you are running a small gas powered generator. All ways figure what the load and surge current load will be before hooking up any generator. Normally this is figured in VA (volt/amps). Wish you lock. GB...stewbison

I am taking a guess here. Now, 7100 Watts is it typical surge wattage. This mean that the generator will deliver 7100 Watt (voltage times current) this is know as the power factor. The actual operating load would be 6800 Watts and I would even operator the generator at its peak wattage. Something in the neighborhood of 10--15% less the peak wattage. Therefore a good positive theatrical Wattage would be 5800 to 6350 operating wattage. Then this generator would run all day.

Just remember Ohm's Law. Current plays a big factor in loading of a generator while the operation voltage is at 120 AC Volts. Example: electric motor; Now electric motor when starting will pull three time its operation current. Operating current for a 1/2 HP AC motor is 6 amperes but start this electric motor will require 18 amperes. This is one reason why they starting capacitors on smaller electric motors. Larger three phase electric motor can literal stop a generator cold...in its tracks. It put such a large demand on the generator it stops the engine powering the generator. I have seen crankshaft break because the generator could handle the heavy current load.

Remember, any time you are running a small gas powered generator. All ways figure what the load and surge current load will be before hooking up any generator. Normally this is figured in VA (volt/amps). Wish you lock. GB...stewbison

Sep 05, 2011 | Robin Subaru RGX7100 7100 Watt Gas...

You may be asking too much of the unit; the 5800 watts a which it is spec'd, may be a 'peak' power rating which may be 15-20% higher than its continuous rating.
30 Amps at 220 volts implies 6600 watts which is higher than even the peak power rating.
I would expect the unit to produce ~4800 watts continuous or around 22 Amps.

Decided to check my statements and found this, which I quote:

Generator Volts AC (60Hz) 120/240 Max. Output Current 5800W-48.3A/24.2A Rated Output Current 4800W-40A/20A Volts DC (AMPS) 12 (8.3)

Decided to check my statements and found this, which I quote:

Generator Volts AC (60Hz) 120/240 Max. Output Current 5800W-48.3A/24.2A Rated Output Current 4800W-40A/20A Volts DC (AMPS) 12 (8.3)

Aug 28, 2011 | Makita G6100R 5800 Watt Generator

This generator is a 5KW model. This means it can supply up to 5000 watts of power, total. Not all devices list the watts they need to be provided - instead these devices list the power they need as volts and amps. This can make it hard to determine what the actual watt requirements are for the device.

Overly simplified, watts is equal volts times amps (watts = volts x amps). A single 120 volt light bulb that uses .833 amps consumes 100 watts. If you checked a regular 100 watt light bulb with an ammeter, you'd find it does indeed draw .833 amps.

Working the formula a different way, we can learn how many amps this 5000 watt generator can supply at 120 volts, too. If all the loads you need to connect to this generator are 120 volt types, that means the total amount of amps the generator can supply is 5000 watts / 120 volts = 41 amps purely resistive loads (like a toaster or light bulb) maximum under ideal conditions. There is never a time when ideal actually happens, and not all loads are purely resistive - many are inductive. Inductive loads are motors (like your A/C), fluorescent lamps, computer power supplies, etc. - so figure more like around 30 amps total instead.

If you try to connect devices that require more than 30 - 35 amps, the generator will probably have problems trying to supply this load for any longer that a short length of time. Additionally, motors like those in A/C compressors draw significantly more power when first starting and can cause the problem you are describing. Try running the generator with loads other then the A/C to see how well it can supply the load(s). Or try running only 1 A/C unit and other non-A/C loads.

What I'm trying to tell you is that you may need to do some active load management to be sure that you aren't trying to get more power out of the generator than it is capable of supplying. You may need additional generators or swap this one to a larger size to handle the load properly and safely.

I hope this helps & good luck!

Overly simplified, watts is equal volts times amps (watts = volts x amps). A single 120 volt light bulb that uses .833 amps consumes 100 watts. If you checked a regular 100 watt light bulb with an ammeter, you'd find it does indeed draw .833 amps.

Working the formula a different way, we can learn how many amps this 5000 watt generator can supply at 120 volts, too. If all the loads you need to connect to this generator are 120 volt types, that means the total amount of amps the generator can supply is 5000 watts / 120 volts = 41 amps purely resistive loads (like a toaster or light bulb) maximum under ideal conditions. There is never a time when ideal actually happens, and not all loads are purely resistive - many are inductive. Inductive loads are motors (like your A/C), fluorescent lamps, computer power supplies, etc. - so figure more like around 30 amps total instead.

If you try to connect devices that require more than 30 - 35 amps, the generator will probably have problems trying to supply this load for any longer that a short length of time. Additionally, motors like those in A/C compressors draw significantly more power when first starting and can cause the problem you are describing. Try running the generator with loads other then the A/C to see how well it can supply the load(s). Or try running only 1 A/C unit and other non-A/C loads.

What I'm trying to tell you is that you may need to do some active load management to be sure that you aren't trying to get more power out of the generator than it is capable of supplying. You may need additional generators or swap this one to a larger size to handle the load properly and safely.

I hope this helps & good luck!

Apr 09, 2011 | Watts Onan Portable Generator - 5000 ,...

Your manual says only plug 20Amp loads into each 120 receptical. See manual at: http://bsintek.basco.com/BriggsDocumentDisplay/default.aspx?filename=fequxHX-nfBhU7y

that would be 4 recepticals tmes 20 = 80 Amps'

80 Amps times 120 V = 9,600 Watts This means that you cannot hook up all 4 outlets at the same time as that would overload the generator all you can hook up would be 2 outlets of up to max of 23 Amps

The manual restricts you to each load no more than 20 amps because some devices such as drills, water pumps exceed their running load upon start up, and would exceed the 20 Amps momentarily, thus 23 amps.

The maximum power load of the generator is 5000 watts and 20 amps at each outlet.

You certainly are within the useful range.

Volts time Amps = Watts

that would be 4 recepticals tmes 20 = 80 Amps'

80 Amps times 120 V = 9,600 Watts This means that you cannot hook up all 4 outlets at the same time as that would overload the generator all you can hook up would be 2 outlets of up to max of 23 Amps

The manual restricts you to each load no more than 20 amps because some devices such as drills, water pumps exceed their running load upon start up, and would exceed the 20 Amps momentarily, thus 23 amps.

The maximum power load of the generator is 5000 watts and 20 amps at each outlet.

You certainly are within the useful range.

Volts time Amps = Watts

Jan 10, 2011 | Briggs & Stratton Briggs and Stratton...

kva = kilo-volt-amps

watts = volts x amps = va

Therefore, 5.8kva = 5800 watts

watts = volts x amps = va

Therefore, 5.8kva = 5800 watts

Mar 24, 2010 | Honda 3000 Watt Portable Generator

probably your AVR card is burnt...

an AVR card is located right outside the stator...looks just like an AK-47 clip (i don't know how else to describe it)...i put a pic below this.

replace it and check again

AVR location

AVR card

an AVR card is located right outside the stator...looks just like an AK-47 clip (i don't know how else to describe it)...i put a pic below this.

replace it and check again

AVR location

AVR card

Dec 28, 2008 | Electrical Supplies

If you got the store bought APC 350 UPS, you most likely overloaded them, and killed them beyound repair.

People should never buy a 350VA. They are way to small for power supplies most of us now have. you need to start out to 1000VA plus you need to do the math to figure out how big of a UPS you actually need in the show room.

What am I talking about? What is the significant, or the math of what I am saying here. 115V x 1 amps = 115VA x .778 power factor = 89.47 watts Start up 50 watts = 39.47 watts

115V x 2 amps = 230VA x .778 power factor = 178.94 watts Start up 50 watts = 128.94 watts

115V x 3 amps = 345VA x .778 power factor = 268.41 watts Start up 50 watts = 218.41 watts

115V x 4 amps = 460VA x .778 power factor = 357.88 watts Start up 50 watts = 307.88 watts

115V x 5 amps = 575VA x .778 power factor = 447.35 watts Start up 50 watts = 397.35 watts

115V x 6 amps = 690VA x .778 power factor = 536.82 watts Start up 50 watts = 486.82 watts

115V x 7 amps = 805VA x .778 power factor = 626.29 watts Start up 50 watts = 576.29 watts

115V x 8 amps = 920VA x .778 power factor = 717.76 watts Start up 50 watts = 667.76 watts

115V x 9 amps = 1035VA x .778 power factor = 805.23 watts Start up 50 watts = 755.23 watts

115V x 10 amps = 1150VA x .778 power factor = 894.70 watts Start up 50 watts = 844.70 watts

115V x 11 amps = 1265VA x .778 power factor = 984.17 watts Start up 50 watts = 934.17 watts

115V x 12 amps = 1380VA x .778 power factor = 1073.63 watts Start up 50 watts = 1023.63 watts

115V x 13 amps = 1495VA x .778 power factor = 1163.11 watts Start up 50 watts = 1113.11 watts

115V x 14 amps = 1610VA x .778 power factor = 1252.58 watts Start up 50 watts = 1202.58 watts

115V x 15 amps = 1725VA x .778 power factor = 1342.05 watts Start up 50 watts = 1292.05 watts

115V x 16 amps = 1840VA x .778 power factor = 1431.52 watts Start up 50 watts = 1387.52 watts

115V x 17 amps = 1955VA x .778 power factor = 1520.99 watts Start up 50 watts = 1470.99 watts

115V x 18 amps = 2070VA x .778 power factor = 1610.46 watts Start up 50 watts = 1560.46 watts

115V x 19 amps = 2185VA x .778 power factor = 1699.93 watts Start up 50 watts = 1649.93 watts

115V x 20 amps = 2300VA x .778 power factor = 1789.40 watts Start up 50 watts = 1739.40 watts

People should never buy a 350VA. They are way to small for power supplies most of us now have. you need to start out to 1000VA plus you need to do the math to figure out how big of a UPS you actually need in the show room.

What am I talking about? What is the significant, or the math of what I am saying here. 115V x 1 amps = 115VA x .778 power factor = 89.47 watts Start up 50 watts = 39.47 watts

115V x 2 amps = 230VA x .778 power factor = 178.94 watts Start up 50 watts = 128.94 watts

115V x 3 amps = 345VA x .778 power factor = 268.41 watts Start up 50 watts = 218.41 watts

115V x 4 amps = 460VA x .778 power factor = 357.88 watts Start up 50 watts = 307.88 watts

115V x 5 amps = 575VA x .778 power factor = 447.35 watts Start up 50 watts = 397.35 watts

115V x 6 amps = 690VA x .778 power factor = 536.82 watts Start up 50 watts = 486.82 watts

115V x 7 amps = 805VA x .778 power factor = 626.29 watts Start up 50 watts = 576.29 watts

115V x 8 amps = 920VA x .778 power factor = 717.76 watts Start up 50 watts = 667.76 watts

115V x 9 amps = 1035VA x .778 power factor = 805.23 watts Start up 50 watts = 755.23 watts

115V x 10 amps = 1150VA x .778 power factor = 894.70 watts Start up 50 watts = 844.70 watts

115V x 11 amps = 1265VA x .778 power factor = 984.17 watts Start up 50 watts = 934.17 watts

115V x 12 amps = 1380VA x .778 power factor = 1073.63 watts Start up 50 watts = 1023.63 watts

115V x 13 amps = 1495VA x .778 power factor = 1163.11 watts Start up 50 watts = 1113.11 watts

115V x 14 amps = 1610VA x .778 power factor = 1252.58 watts Start up 50 watts = 1202.58 watts

115V x 15 amps = 1725VA x .778 power factor = 1342.05 watts Start up 50 watts = 1292.05 watts

115V x 16 amps = 1840VA x .778 power factor = 1431.52 watts Start up 50 watts = 1387.52 watts

115V x 17 amps = 1955VA x .778 power factor = 1520.99 watts Start up 50 watts = 1470.99 watts

115V x 18 amps = 2070VA x .778 power factor = 1610.46 watts Start up 50 watts = 1560.46 watts

115V x 19 amps = 2185VA x .778 power factor = 1699.93 watts Start up 50 watts = 1649.93 watts

115V x 20 amps = 2300VA x .778 power factor = 1789.40 watts Start up 50 watts = 1739.40 watts

Sep 16, 2008 | APC Back-UPS ES 350 - UPS ( external ) -...

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