Oct 14, 2015  Rumus Listrik Ampere, KW, KVA,PF, HP. Untuk mengetahui berapa amper yang diperlukan harus diketahui dulu tegangan kerja dan fasa yg akan digunakan pakai 1 phase atau 3 phase? Jika semuanya sudah diketahui maka tinggal hitung menggunakan rumus diatas. Salah satu karakteristrik sistem 3-phase adalah bila sistem 3-phase tersebut mempunyai beban yang seimbang, maka besaran arus phase di penghantar R-S-T akan sama sehingga In (arus netral) = 0 Ampere. Contohnya pada gambar diatas: misal ketiga rumah tersebut mempunyai beban yang identik seimbang.

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Untuk single phase 220 V: 1 hp = 745,7 watt: 220 V = 3,39 Ampere. Untuk 3 phase 380 V: 1 hp = 745,7 watt: (380×1,73) = 1,13 Amp. Dengan catatan semua perhitungan dengan menganggap Cos phi nya = 1 (satu). Demikian semoga bermanfaat.

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1. Plastic

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   3 phase '100 amps per phase' can someone explane 'phases' to an idiot?

   I am trying to move into a small place to do some metalwork. Ideally I'd need 150 amps but 100 amps would be OK. I have a 65 amp machine but trying to get a machine that can go up to 130 amps but I control the amperage besides it will be a while and I need a place to get it up and runing and dialed in. I talked to a broker and they told me a place had 3 phase, 220v, '100 amp per phase), I asked if I run 3 phase that would be 300 amps? He gave a confident 'yep' but I'm not sure it works that way. Is there such a thing? I'm not sure abot this whole 'phase' thing, my impression is that rather than single big waves electricity coming at one time, it's split into 3 smaller waves coming separately.
   It's not like I take all 3 phases and add up the voltages and amps do I? then why isn't 3 phase 360v in most places?
   Note: I also spelled 'explain' wrong in the title, further solidifying the fact I need this whole 'phase' thing explained to me like I'm an idiot

2. Diamond

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   There are 100 amp on each phase, and 220 volts on each phase. But, that does not get you 300 amps because whatever you hook up draws it's amps on each phase.
   Sounds like a 100 amp service.

3. Stainless

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   First tell use what this machine is that needs 65 amps but you can go up to 130.... is it a single phase machine or what? Are you talking input current or output, and output of what?
   The max you can draw from a 220v 100 amp supply, three phase or not, is 100 amps. In theory you could have three separate single phase devices each drawing 100 amps at 220v, or one three phase device at 100amps.
   220 is an uncommon voltage for supply - more likely it's 240 or 208v?
   It get further complicated - Does this new location have a 100amp breaker or is it rated for 100 amp supply? You won't be running 100 amps though a typical 100amp breaker for long.

4. Titanium

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   I'm thinking the OP is talking welders ,a 130 amp welder doesn't need 130 amps going into it because voltage will be much lower ,as said above more information is needed.

5. Hot Rolled

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   Yeah, like sable said. If you're talking about a welder, look on the tag for input voltage requirements. !00 amps per phase is still only 100 amps, it don't add up when using 3 ph. A 130 amp welder won't take close to 100 amps.

6. Cast Iron

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   Well if it is a welder, 65 amp output is unlikely. I suspect he's looking at a very large TIG machine or similar. My 352? ESAB takes 110 amp input 240V single phase for full output current. He seems to know that he needs a lot of power anyways, and it sounds like the broker is snowing him.

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   I have one plasma cutter that goes up to 65 amps, and another table with a 130 amp plasma cutter I'm trying to get set up and running, but I do not expect to be cutting anything requiring 130 amps any time soon. I will only be cutting 3/16-1/4 at the most which requires 65 amps.
   Thanks guys, this confirms what I thought.

8. Titanium

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   I can't tell if you're talking input or output of these machines and that would make a large difference here.

9. gnorbury

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   Check the ratings plate for input amperage and voltage. If it's not listed, look for the equipment wattage and work back from there. Watts/volts = amps (broadly speaking, ignoring power factor etc)

10. Cast Iron

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    I believe Metricar is talking about a 65 amp (output power) plasma cutter and another 130 amp (output) plasma cutter. The output power amperage will be totally different than the input power requirements.
    First.....the power in your household 120 outlets is single phase, 120 volts (N. America). There are two prongs for the power, and one is a safety ground. It is called a 3 wire single phase. There also are single phase household outlets for things that use more power, such as an electric stove, an electric dryer. These outlets typically will have 4 wires or 4 prongs, measuring across the two main hot wires you will see 220 volts (or 208 or 240), and measuring from each hot to the neutral you will see 120 volts. This is called 'split phase 120/240), the fourth prong is for safety ground. There also are 3 wire 240 volt single phase circuits...these will measure 240 volts across the two hot legs, there is no usable 120 volt path, and the third prong is for safety ground.
    In most commercial buildings there is 3 phase power, which is much more efficient for powering industrial equipment. A 3 phase power outlet will have 3 wires for power, and if it is 220 volts you could measure 220 volts between any combination of the 3 wires. 3 Phase in N. America is normally available in 208, 220 or 240 or 480 or 600 volts (Canada). The higher the voltage, the more efficient and powerfull the circuit will be. Higher voltage allows more amperage to travel longer distances through smaller wires sizes.
    If your 65 amp unit is a Hypertherm Powermax 65...it is designed to operate on any input voltage between 200 and 600 volts, single or three phase. It cuts the same with any voltage input (some plasma systems put out lower cutting power with lower input voltage), but will use less input amperage and require smaller input circuit and wiring sizes if you operate it at higher input voltage and /or on 3 phase power. Further, on higher voltage inputs and on 3 phase circuits, the duty cycle will be higher as the power supply is more efficient on these circuits.
    The Powermax65 will draw as much as about 60 amps on a 240 volt input power line when cutting the thickest materials. If you are running on a 600 volt 3 phase input power line...the 65 will draw about 15 amps per phase. (these numbers are off the top of my head as I do not have the operators manual in front of me)
    The HPR130 or the HSD130 from Hypertherm will only operate on 3 phase voltages as it is strictly an industrial machine, and draws too much power to efficiently operate on a single phase circuit. These units must be purchased for the voltage level you have, so if your shop has 240 volt three phase, the unit must be built for that voltage.
    Hopefully this helps a bit.
    Best regards, Jim Colt Hypertherm
    

    Originally Posted by metriccar

    I have one plasma cutter that goes up to 65 amps, and another table with a 130 amp plasma cutter I'm trying to get set up and running, but I do not expect to be cutting anything requiring 130 amps any time soon. I will only be cutting 3/16-1/4 at the most which requires 65 amps.
    Thanks guys, this confirms what I thought.

11. digger doug, JRIowa, Rob F., 9100, dsergison and 1 others liked this post
12. Diamond

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    Yup, what Jim said...AND to add, I just wired up a T.D. (not my choice) a-120 plasma
    supply for a cutting table, input at 220 vac 3-phase was 62 amps.

13. Titanium

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    If it is 3-phase 20 amps, each phase has 20 A. Just look at the fuses.
    Even if you draw 10 A from every phase -with a single phase equipment-, the neutral will only see 10 A.
    If you pull 10 A at each phase with a 3 phase motor, the neutral sees no current. At 230 V, it will be 6.9 kW
    Unless you have some fancy 3 phase, where the phases are not at 120 degree.
    Nick

14. Diamond

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    Originally Posted by Nick Mueller

    If it is 3-phase 20 amps, each phase has 20 A. Just look at the fuses.
    Even if you draw 10 A from every phase -with a single phase equipment-, the neutral will only see 10 A.
    If you pull 10 A at each phase with a 3 phase motor, the neutral sees no current. At 230 V, it will be 6.9 kW
    Unless you have some fancy 3 phase, where the phases are not at 120 degree.
    Nick

    Are you sure about that??
    reason I ask is that I used to install machine tools and durring the run off testing we made a full HP cut and used the Amprobe meters to check the current in each of the 3 wires going to the motor...ALL 3 were the same current....
    Where would the Neutral wire be?

15. Titanium

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    You don't need to draw the same current from all phases. My heat-treating oven draws a funny mix from 0 to 20 A per phase. A 3 phase motor does draw the same current on all phases (minus some differences).
    Depending on your load, you don't need a neutral or not. My funny oven does, a 3 phase motor not. Neither in wye nor delta.
    It simply depends on the kind of load.
    Nick

16. Diamond

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    Originally Posted by Nick Mueller

    You don't need to draw the same current from all phases. My heat-treating oven draws a funny mix from 0 to 20 A per phase. A 3 phase motor does draw the same current on all phases (minus some differences).
    Depending on your load, you don't need a neutral or not. My funny oven does, a 3 phase motor not. Neither in wye nor delta.
    It simply depends on the kind of load.
    Nick

    Is the odd mix of currents due to switching different combinations of heaters to control the amount of heat? I had an oven like that once that controlled wattage by switching different series combinations of lower voltage elements between delta and Y. I was trying to get a 3 phase line at the time and running into objections from the power company because I did not have enough load to meet their requirements. I simply could not make them believe that I had a 3 phase oven and I did not have enough machines to make the load requirement because running on a phase converter was strangling me. They did finally give me a line.
    Minor quibble- Jimcolt obviously knows what he is talking about, but I have always heard the term 'split phase' applied to capacitor start motors with a centrifugal switch. Jim's post is the second time recently I have seen it used about a 120-0-120 line. Has terminology morphed?
    Bill

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    Is the odd mix of currents due to switching different combinations of heaters to control the amount of heat?

    It has tree stages. And depending on which one you use, more elements are added. At the lowest stage, there is just one element (at the bottom), next stage is bottom + 2 on the side and third stage is an extra one on the top. Bottom, side and top have different wattages.
    And there is an extra element that heats the temperature sensor. Astonishing enough, that takes out thermal inertia of it. Compared to an other thermometer in the middle of the oven, they both are off maybe 10 °C, even during heating up.
    So:
    At least here, no one forces you to use the same load on all three phases (at least, I don't know). The lighting in my shop actually is connected to three phases (each group its own). So if one phase fails, I'm not standing in the dark (with a machine still running).
    I know, the US electricity is a bit odd compared to ours, so things might be different.
    Nick

18. Stainless

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    Originally Posted by 9100

    Minor quibble- Jimcolt obviously knows what he is talking about, but I have always heard the term 'split phase' applied to capacitor start motors with a centrifugal switch. Jim's post is the second time recently I have seen it used about a 120-0-120 line. Has terminology morphed?
    Bill

    Nope... That's how I've always heard it. It is technically correct- not '2 phase' as some like to think of it. Maybe the internet just make the terminology more universal and accessible?

19. Stainless

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    Originally Posted by Gary E

    Are you sure about that??
    reason I ask is that I used to install machine tools and durring the run off testing we made a full HP cut and used the Amprobe meters to check the current in each of the 3 wires going to the motor...ALL 3 were the same current....
    

    Motors draw the same current per phase by design. Other items do not have to. A standard 3 phase panel distributes load per phase, and they are most certainly not equal in a mixed use environment.

20. Diamond

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    Originally Posted by Nick Mueller

    Astonishing enough, that takes out thermal inertia of it. Compared to an other thermometer in the middle of the oven, they both are off maybe 10 °C, even during heating up.Nick

    That is known as an anticipation heater. Because of the lag in heat from the heaters getting to the sensor, it will keep the heat on too long, then after it shuts off the overall temperature will overshoot. When I built gyros, that was a serious problem. Integrating gyros were sealed in a can surrounded by another with the gap filled with a damping fluid that was a paste at room temperature. Operating temperature was 160 F. A large overshoot would boil the damping fluid and blow the end off. The solution was to use a resistance wire sensor with a few turns of heater wire wrapped over it with only a thin layer of insulation between them. The anticipation winding would cause the temperature control to shut off early, the internal mass would absorb heat, the control would turn back on and shut off early again, repeating the cycle as the temperature staircased up, finally stabilizing on the right temperature. The temperature controls were primitive, tube amplifiers sensing the output of a resistance bridge. Modern computerized controls have compensation built in, allowing the user to tailor the response to the individual system. In some ways I don't miss the 'good old days'.
    Bill

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    Originally Posted by Gary E

    ALL 3 were the same current....Where would the Neutral wire be?

    Sounds like you had delta power with no neutral, which is an extremely common configuration.

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With this calculator you can convert online from Hp to Amps or Amperes to Hp automatically, easily, quickly and free.

For ease we explain how to convert from Hp to Amps in only 3 step, that the formula is used for the calculation, some examples and a table with the main conversions of Hp to Amps.

We also show the most common power factors in addition to efficiency values.

3 Phase Technologies

More information of calculator from Hp to Amps:

• Typical common efficiencies of electric motor ODP and TEFC.

Hp to Amps calculation formula, DC, AC, 3 phase, 2 phase, 1 phase:

• I_DC=Direct current.
• I_AC1Ø=Current/Ampere 1 phase.
• I_AC2Ø=Current/Ampere 2 phase.
• I_AC3Ø=Current/Ampere 3 phase.
• H.P=Horsepower.
• V_DC=Voltage direct current.
• VL-N=Voltage line to neutral.
• V_L-L=Voltage line to line.
• _Ef=Efficiency.
• P.F=Power factor.

How to convert Hp to Amp AC 3 phases in only 3 step:

Step 1:

Multiply Hp (Horsepower) by 746. Example, if you have 100 hp multiply by 746 and you get 74600. (100Hpx746 = 74600).

Step 2:

Multiply the AC voltage by the motor efficiency, the power factor and the square root of 3. For example, if the motor is 220Vac, it has an efficiency of 80% and the power factor is 0.9, it must Multiply 220Vdc by 0.8 (80%) by 0.9 by √3 (square root of 3) to obtain 274,35 (220Vdcx0.8×0.9x√3 = 274,35).

Step 3:

Finally divide step 1 and step 2. For example, (100Hpx746) / (220Vdcx0.8×0.9x√3) = 271,9Amps.

How to convert Hp to Amp DC in only 3 step:

Step 1:

Multiply Hp (Horsepower) by 746. Example, if you have 100 hp multiply by 746 and you get 74600. (100Hpx746 = 74600).

Step 2:

Multiply the DC voltage by the efficiency of the motor. For example, if the motor is 220Vdc and has an efficiency of 80%, multiply 220Vdc by 0.8 (80%) to get 176. (220Vdcx0.8=176)

Step 3:

Finally divide step 1 and step 2. For example, (100Hpx746) / (220Vdcx0.8) = 423,86Amps.

Examples of hp to amp conversions:

Example 1:

A mine dredger has a power of 80Hp, AC, 4160V (L-L), three phase, with an efficiency of 84% (0.84) and a power factor of 0.8. How much amperage does this machine have?

Rta: // The first thing to do is multiply the Hp by 746, then you must divide the previous result between the multiplication of the voltage line line, the efficiency, the root of three and the power factor, giving as a result: 12.33 Amps . (80Hpx746) / (4160Vacx0.84 × 0.8x√3)

Example 2:

An air conditioning system has a power of 5.4Hp, three phase, with a voltage line line of 220 Volts, an efficiency of 0.88 and a power factor of 0.9, how much amperage does this equipment have ?.

Rta: // You must multiply 5.4Hp by 746 and then divide the result by multiplying the rest of the variables, as shown below: (5.4Hpx746) / (220Vacx0.88 × 0.9x√3) = 13, 35 Amps.

Example 3:

An industrial blender of 50hp, bifasica, has a line-neutral voltage of 277 Volts, with an efficiency of 90% (0.9) and a power factor of 0.8, which will be the amperage of the blender ?.

Rta: // It’s simple you just have to enter the previous values ​​in the calculator and it will easily give you the result that is: 46.76 Amps.

Hp to Amps conversion chart-table:

The information in this chart was derived from Table 430-148 & 430-150 of the NEC and Table 50.1 of UL standard 508A. The voltages listed are rated motor voltages. The currents listed shall be permitted for system voltage ranges of 110-120, 220-240, 380-415, 440-480 and 550-600 volts.

The full-load current values are for motors running at usual speeds and motors with normal torque characteristics. Motors built for especially low speeds or high torques may have higher full-load currents, and multi-speed motors will have full-load currents varying with speed. In these cases, the nameplate current ratings shall be used.

Caution: The actual motor amps may be higher or lower than the average values listed above. For more reliable motor protection, use the actual motor current as listed on the motor nameplate. Use this table as a guide only.

Typical Un-improved Power Factor by Industry:

Typical power factor of common household electronics:

Typical Motor Power Factors:

Reference // Power Factor in Electrical Energy Management-A. Bhatia, B.E.-2012
Power Factor Requirements for Electronic Loads in California- Brian Fortenbery,2014
http://www.engineeringtoolbox.com

NEMA Design B Electrical Motors Efficiency

Electrical motors constructed according NEMA Design B must meet the efficiencies below.

¹⁾ NEMA Design B, Single Speed 1200, 1800, 3600 RPM. Open Drip Proof (ODP) or Totally Enclosed Fan Cooled (TEFC) motors 1 hp and larger that operate more than 500 hours per year.

How to use the Hp to Ampere calculator:

The first thing you have to do is enter the Hp you want to convert, then you must choose the type of AC or DC current, it is very important that once you choose the voltage type, be aware of what the table asks for on the left side; then enter the number of phases, this option only applies to the AC current, then you must enter the efficiency.

Continue entering the voltage, at this point it is very important that you verify what is the voltage requested by the calculator (line-line voltage or line-neutral voltage), otherwise the result may not be correct, finally you have to enter the factor of power, if you do not know the latter you can see the most common values.

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