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Why does a 120V-240V dual voltage single phase table saw motor produce 4 times more torque at 240V than at 120V?
I believe it has to do with the windings in the motor. When wired to 120V, half the motor has a positive polarity and the other half has a negative polarity. Then as the current alternates (60 hertz AC) the polarity flips, the magnetic poles oppose each other and cause the motor to spin. I think in a 240v winding the motor is in quadrants instead of halves. So it would be like have 4 magnets opposing each other instead of two and you have double the voltage. Answer The calculation for electrical power (which is converted to torque) is voltage-squared divided by the resistance. If the voltage is doubled, the power is increase by 2-squared, or quadrupled. In reality, the torque produced will be slightly less than 4 times more (because some of the power is lost as heat), but it should be pretty close. -- The second answer is the best answer. The first answer could suggest several things, depending on how you read it. Nonetheless, they are all incorrect. The power calculation (in Watts) is really all you need to do. Voltage squared, divided by resistance. Resistance stays the same, so power quadruples when voltage doubles. If the motor spins at the same speed, then torque should effectively be linear with power, aside from the extra heat created in the components from the higher current.
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Note "2-phase" to describe US residential service is depricated nomenclature. US residential service is single phase because the two hot supply phases have 0 degrees of separ…ation between their phases: therefore they are in phase. The two phases are pulled from 2 out of 3 corners on a 240v (line-to-line) 3-phase delta-primary transformer, usually out in the street. (Sometimes at your house if it's a big one). Basically all power is generated and transmitted as 3-phase. Usually around 415V 3-phase comes into the primary of the 3-phase transformer. (It could be delta- or wye-connected.) The secondary windings for all three phases will each have a center-tapped connection, and that's grounded at the panel. This is the neutral wire. All circuits in houses return via the "common" or "neutral" wire to this point, which happens to be grounded at the panel. Note: no neutral wires should be grounded anywhere else. The two "corners" are 240v relative to each other, and 120v each to the center tap. Each 240V circuit really is two hot wires plus a neutral, which is why it's often wrongly called two-phase when in fact it's just single-phase. For each 120V circuit in the house you're going to use one hot wire and one neutral wire. The neutral wire provides a return path for currents back to the generating station. In some installations, such as apartment blocks, the third leg of power would be at 208V with respect to the center tap. Another answer Just what does "220v single-phase split ac in the US which has a 110v 2-phase system" mean? The vast majority of electricity in the US is delivered as single phase or three phase. The only areas in the US that use 2-phase [for industrial and commercial purposes] are Philadelphia/South Jersey [where it is being phased out-no joke intended] and somewhere out west... It was one of the early poly-phase options pursued because of the natural magnetic differential between phases [makes motors spin without a capacitor] Most residences receive 220-240 volt single phase electricity with a grounded center-tapped neutral, the purpose being to limit voltage to ground to less than 150 volts from either "hot".
I'm assume you're not working on a polyphasic system, so you have 2 hots and one neutral with 220VAC across the hots and 120VAC across either hot and neutral: The motor shoul…d have two sets of windings inside. The leads for these windings should be behind a cover plate or in a junction box. Since the motor is currently wired for 115V, the windings should be in parallel. Write down which wires are connected to what. This is very important in case you make a mistake! A good way to think about this is you have four wires, numbered 1 - 4. Winding one has two leads, 1 and 2. Winding 2 has two leads, 3 and 4. Right now 1 and 3 are connected to the hot, and 2 and 4 are connected to the neutral. To wire the motor in series you want 1 connected to hot1, 2 connected to 3, and 4 connected to hot2. -EDIT- There was a mistake in my first revision. The method wouldn't work for 110-220 conversion as a mistake could burn up a winding. -TJNII First, figure out which wires are winding pairs. This is very important as if you try to rewire it blind, you could burn a winding out. After writing down which wires were connected where, disconnect all junctions. Connect your multimeter (on resistance) to one of the wires you disconnected from the hot. Find out which wire from the neutral is paired with it. The matching lead will have a fairly low resistance. You know know which leads are 1 - 4. Wires 1 and 2 are the pair you just found, and wires 3 - 4 are the pair you didn't need to test. Wires 1 and 2 connected to the hot, and wires 3 and 4 connected to the neutral. Connect 1 to hot1, 2 to 3, and 4 to hot2. Check the resistance across 1 and 4. If it is not about double the restance you found in the above step, you made a mistake. Re-check your wiring. The motor should now run. If the motor tries to turn but cannot, or turns slowly while humming very loudly, wires 1 and 2 are reversed. Do not run the motor with the windings in parallel, or run a single winding off 220V! You will burn it out! The linked site has just about any connection you might need. See related links below.
Answer Cost is based on watts not voltage...pkazsr
If you work in an industrial setting how do you make a 120V single phase line into a 240V single phase line?
Get an electrician If you work in an industrial setting and DON'T know how to do this, you should keep your hands off it. You are not a suitably quali…fied individual. * National Electrical Code definition, NFPA 70 2005 Article 100 I: Qualified Person. "One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training on the hazards involved." * Performing any such operation without suitable qualification subjects your employer to action by OSHA. Read that as: "financial penalty"
Answer If You Are Asking Which Will Cost Less. That Is Say A Motor ( Dual Voltage ) It Will Cast The Same To Operate On 110V As It Will 220 Volts. Reason You Onl…y Pay For Killowatts. Watts And Voltage Are Two Different things. If You Will Look On Name Tag Of Said Item You Will Find Amperage At A Given Voltage. example 110V 10 amp == 220v 5 amp Volts X Amps = Watts in either equation you are using 1100 watts. So You Will Pay The Same Price For Usage Of Said Unit. If Whatever You Are Running And It Was Built To Run On Either Voltage, The Cost Will Be The Same. Will It Run As Efficient ? It Should If It Was Designed To Run On Either Voltage. HOPE THIS HELPS
Single phase 4 pole Gen alt w 240V 60hz output no neutral. you check from each lead to ground and get 50-70V How do you get a neutral for connecting Gen to a standard breaker box having 240V and 120V?
Answer Neutral is at the jumper that changes it from 120v to 240v. Two stator windings are used in series to make 240v; at that junction is (when wired in… Series)your neutral/common/ground. Ground this terminal and use it for your neutral/common. When wired in parallel you have 110v and the jumper is removed and there is no common/neutral and ground is from the frame of the generator.
If you replaced a table saw motor from a 2 HP 120V 30A to a 3HP 240V 15A Is the existing 14ga wiring on the saw okay to use or do you need to upgrade to a heaver wire?
Answer That's right on the cusp. 15 amps is the maximum draw for 14 awg wire. I'd upgrade to 12 awg to be safe. Answer Unless you know e…xactly what you are doing, go no further! There is a big differenc between 120 Volt wiring and 240 Volt wiring. You run the risk of burning up the motor, injuring yourself, and possibly starting a fire. You are proposing making a major modification to this saw, which, if not done properly, will be very dangerous! What you want to do can be done, but only by a qualified technician. Look for a small equipment shop, electrician, electric motor specialist, or millwright to help you.
How can you convert US 120V or 240V circuit into a single-phase 240V circuit to use on a European appliance?
The voltage isn't a problem, you can run 220 from your house and use that to run a European appliance, the problem is whether the appliance is dependant on line HZ. Euro…pean is 50HZ and US is 60HZ. If the appliance specifies 220/50HZ, it will probably give you trouble here. If it says 220V/50 or 60HZ
Answer it won't work properly
If it is a six wire motor go to http://apps.motorboss.com/connections/108323.pdf
How do you get a split phase 120v 240v power supply from a single phase 240v supply for an American RV with a 50 amp service?
This is a common misconception. A standard 240 utility feed, common in the US, and a 120/240 feed are one in the same, the exact same thing. It is called (historically) an Edi…son connection. If you have a 240 volt single-phase supply, with two hot conductors, a neutral, and a ground wire, then you already have 120/240 service. If you do not understand the terms above, then hire a qualified electrician to make the connection for you. IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB SAFELY AND COMPETENTLY REFER THIS WORK TO QUALIFIED PROFESSIONALS. If you do this work yourself, always turn off the power at the breaker box/fuse panel BEFORE you attempt to do any work AND always use a meter or voltage indicator to insure the circuit is, in fact, de-energized.
A simple way to look at it is to assume you were spinning a wheel by hand and you were spinning it harder once per revolution. If you applied a load of some sort to the wheel …it would slow over a period of time depending on the load. If you continued to manually try and keep the wheel spinning at the same rate, one revolution at a time this would effectively be adding torque to the wheel once per revolution. If you manually mimiced a 3-phase motor you would be manually spinning the wheel 3 times each revolution. This would basically apply three times the torque if each spin used the same force as the single spin did.
Many motors have the ability to run on 240 or 120 volts. There is typically a diagram on the rating plate on the motor that shows you how to wire for either voltage. Sometimes… you need to install or remove jumpers. If your motor is not dual rated you can't easily convert because if you just connect 120 volts to where 240 volts were connected you will draw twice the current which isn't good for a lot of reasons.
Can you take single phase of 120V with a hot wire and a neutral step up to 480v and then step down to 2 phases of 120V or do you have to input 2 phases of 120v to get 240V out?
Theoretically that can be done with transformers, but the power available would still be limited by the circuit breaker on the original 120 v supply.
The US system is not a two-phase system; it's a split-phase system. But, to answer your question, probably not without damaging the Japanese device.
The US does not use a two-phase system. In fact, two-phase systems are very rare, these days. A two-phase system is where the phase voltages are displaced by 90 degrees, where…as the system used in the US is a split-phase system in which one secondary phase winding of a distribution transformer is centre-tapped and grounded (earthed). This provides 240 V between opposite ends of the phase winding, and 120 V from either end to the centre tap.
How do you Convert 240V single phase to 240V and 120V single phases split ac system for testing purpose basically Indian system to US system?
It can't be done because the 240 v supply has a live and neutral. A split-phase 120/240 has a centre-tapped neutral so both outer wires are live at 120 v. It can onl…y be done with a 240/240 v transformer with a centre-tapped secondary.