Electrical Wiring

75 HP = 55 KW

55 = 31/2 x 0.220 x I x cos φ = 31/2 x 0.220 x 0.8 x I

I = 55/(31/2 x 0.220 x 0.8) = 180,42 A

3 x 70 mm2 is the size of cable for 75 HP 220 Volts 3 phase motor

The bigger the pipe the less resistance to water flow which is analogous to the electrons in current flow. As you make the pipe narrower the resistance to water flow would increase (Less water would flow). Hence higher resistance means lower current in both water and electrical example.

If you had a big vat filled with water and a spigot at the bottom you could turn on and off, you could simulate voltage and current.

The water in the vat represents the potential voltage or stored electron charge. With the spigot off the voltage is constant and the current (flow) is zero. If you open the spigot a small amount you get a trickle of water flowing since the resistance is very high. This will make the water (potential) last longer like a battery that has a small load. As the spigot is opened more, more current flows and the quicker the potential will be reduced to zero.

No, you cannot get a three phase supply directly from a single phase supply.

Nowadays electronic inverter units can be bought that will do the job. For very low power loads the cost of such invertors is quite reasonable but for high power loads they are very expensive.

For high-power industrial uses the most economical solution is to have a 3-phase service installed by the local electric power utility company.

A Single phase induction motor includes a main winding, an auxiliary winding, a run capacitor, & a subsidiary star device. The auxiliary winding is configured such that the number of turns of the aauxiliary winding through which a current flows, varies according to the operating mode of motor. When the motor starts, the number of turns of the auxiliary winding through which a current flows is reduced there by increasing the start efficiency of the motor. when the motor runs in normal mode, the number of turns of auxiliary winding through which a current flows is increasing there by increasing the operations efficiency of motor

Your question should read, 'How much clearance is needed between LINES.... (not 'phases')?' The answer will depend on local authority regulations. The clearances in air tolerated by REC companies in the UK is 90 mm line to line and 127mm phase to earth. Even though there is a greater potential difference between line to line, the gap is less. I think it's to do with public safety if it flashes to earth.

== == == == It's a receptacle symbol, usually with "GFCI", "G", or "GFI" written under it. To find out exactly which symbol is used on your prints, look at the electrical legend, which is normally page E-1, E-001, etc.

A 480 v three-phase system has 480 v between live lines and 277 v from each line to the neutral. This type of supply is common in North America for supplying for example small factories that need more power than a 120/208 v three-phase system can supply.

Turning the breaker on allows the power to flow through to the outlets, lights, and appliances on that circuit, so yes power goes to and through a turned on breaker. If the breaker is off, but the main power is on, power still get to the breaker, usually from the bus bar that runs down the middle of the back of the breaker box.

In a high voltage installation, with the same power, current drawn is small compared to those in low voltage. However it requires a thicker insulation, thus cost of insulation is significant compared to the conductor cost.

By using a star connected winding, the insulation voltage required is equal to line to neutral connection, otherwise if it is connected in delta the insulation rating has to be provided for a line to line connection.

Despite having a higher current, the total cost is still lower compared to using a higher insulation rating.

You need also to know the resistance of the cable. First you establish what the current of the load is. Then from that you calculate the wire size. From a wire size chart you find the wire resistance. Then use the formula I (squared) x R.

Best to get quotes from two or three licensed electricians for the installation of the necessary extra fuses, breakers, etc., testing and commissioning (= handing over to customer to use) of a 120V panel for as many circuits as you want. Though the question does not specifically ask about DIY ("Doing It Yourself"), if you are not a licensed electrical technician you should not even think of doing this kind of work as a DIY project because 3 phase 240V power supplies can kill you if you don't know exactly what you are doing. Depending on your local wiring codes and regulations, it may be illegal to attempt to do such work if you are an unlicensed person.

1 for every 13 outlets, lights etc plus one for each major appliance ( heavy duty ) The minimum *required* number of circuit breakers will be dictated by your local building codes, so there is no one answer that will fit all. If you are planning on building or remodeling a house and are just interested in a back of the envelope estimate, keep in mind that up to a point, more circuits, and thus circuit breakers, are better than fewer. At a minimum, I would use a dedicated circuit for each of: - the furnace - the air conditioner - the refrigerator - the stand alone freezer - the basement lights (or the lights for where ever the breaker box is located) - the sump pump (if you have one) - the water pump (if you have one) - the garage door opener By using a dedicated circuit for each, you minimize the chance of a malfunctioning device or frayed extension cord causing the shut down a critical house hold system. From there it's a matter of how many rooms and outlets. For a family room with an entertainment center, computer equipment, etc., two circuits for the outlets and one for any overhead lights would not be unreasonable. On the other hand you might have two bedrooms share the same circuit for wall outlets and another shared circuit for the ceiling lights. If each room has its own air conditioner, the ideal situation is to locate an outlet by the window which is a circuit dedicated just for that air conditioner. As an aside, ground fault detectors are a must for the kitchen and bathroom, but use self contained ground fault outlets rather than a ground fault circuit breaker for these areas. Ground fault circuit breakers are best for outdoor circuits, like outdoor lighting, swimming pools, etc. While the building codes may dictate a minimum number of circuits needed, based on the size of the house, there is nothing to stop you from having more. What you will need to do however, is make sure you do not exceed the capacity of your electrical service. For that the services of a licensed electrician are highly recommended.

A 3-phase rectifier bridge can be used with a single phase supply, it just means that four of the diodes are not connected. The peak voltage (if a reservoir capacitor is used) is sqrt(2) times the rms supply voltage and the average voltage using inductor smoothing is 0.9 times the rms voltage.

Most 3-phase welders cannot be made to function on single-phase power. If your welder is an inverter type, such as a Miller Dynasty or Lincoln Invertec, then it may have a single-phase mode with reduced current output. You would have to download the manual for your particular welder. If it is an older transformer (big and very heavy), then you're probably out of options here.

At least 50mm but with all the de-rating factors it might be 70mm that's if its 2 cable single phase non armoured clipped direct. Check out the tables dopey!!!!

FYI 50 mm = 2 inches, 70 mm = 2.75 inches these are not wire sizes, sound more like cable outside diameters.

Correct answer

The wire size is dependant on the insulation factor on the wire. A few common insulations and corresponding wire sizes for 150 amps are - Size 0 R90 good for 155 amps, also with insulations of RW 75, TWH, TW75, good for 150 amps. Size 000 TW good for 165 amps.

This is the schematic for the starter. K1T is a timer. Initially KM1 and KM3 are closed to start the motor. Then KM2 is closed and KM1 is opened to run the motor This is the equivalent ladder logic using relays and timers.

Both conductors are at ground potential. They are connected together with a bonding jumper at the panel. The primary difference is the neutral is used as the return current path for single-phase loads, and the ground is the return path for fault current only. So, unless the hot conductor accidentally comes in contact with, say, a grounded equipment cabinet, there would be no current flow on the ground wire. The neutral wire carries current any time the single-phase load is in operation. With a three-phase balanced load, no neutral is necessary or required, yet electrical codes still require a ground wire for safety.