Electrical Engineering

A three-phase motor typically has three sets of windings arranged 120 degrees apart around the stator core. It is larger and more robust compared to single-phase motors, with a more complex wiring configuration. The motor may have six leads coming out of it, instead of just two like in single-phase motors.

A coil with an iron core and a movable iron bar constitutes an electromagnet. When an electric current flows through the coil, it generates a magnetic field that attracts the iron bar, causing it to move. This device is commonly used in various applications such as in electric motors and doorbells.

frequency of the power supply it is connected to. The speed of a single phase motor is directly related to the frequency of the alternating current (AC) power supply. As the frequency of the power supply changes, the speed of the motor will also change.

My understanding of this odd situation is this:

The power generation in the Philippines was originally set up pre-WWII, when it was a colony of the USA. They naturally followed the American standard of 110V, 60Hz.


Later, when the Philippines became independent, they wished to change their power supply to match most of the rest of Asia, i.e. 220v 50Hz. They went ahead, but discovered that the General Electric generators that had been installed in all their power stations only ran at 60 cycles. So, instead of replacing the machines, they simply converted the power supply to 220v, but it remains at 60Hz. This has meant historically that any motorized equipment not specifically designed for this singular situation would either run to fast (110v 50Hz) or wouldn't work at all because the voltage was insufficient to power the motor (220v 60Hz).


With many of today's electronics being multi-voltage/multi Hz, this is increasingly less of a problem, but simpler appliances like hair dryers, turn-tables, microwaves etc. are still problematic.


This is how an old friend who's lived in Manila for 30 years has explained it to me. Any comments on it's accuracy?

field. This phenomenon is known as electromagnetic induction and is the principle behind how electric generators work by converting mechanical energy into electrical energy. Faraday's law of electromagnetic induction states that a changing magnetic field induces an electromotive force (EMF) in a conductor.

A lumen is a unit of luminous flux. It is represented by the abbreviation 'lm'.

One lumen equals the amount of light emitted in a solid angle from a source that radiates to an equal extent in all directions.

A generator converts mechanical energy into electrical energy.

No, an electric motor requires a magnetic field to function. The interaction between the magnetic field and electric current generates the force that drives the motor's motion. Without a magnet, the motor would not be able to convert electrical energy into mechanical energy.

The number of BTUs needed for heating or cooling a space depends on factors such as the size of the space, insulation, climate, and specific needs. It is typically calculated by measuring the square footage of the area and applying a BTU per square foot ratio. Consulting with a professional HVAC technician can provide a more accurate assessment for your specific situation.

Remember always that the classical picture of the hydrogen atom is wrong, completely wrong, totally wrong in nearly every possible way. Other than that, yeah, half an Angstrom is about right for the Bohr radius of hydrogen.

You check on the ends of the immersion heater elements. The wattage will be stamped on it. The other thing you can do is look at the instruction manual and find the specs. for the tank. Watts = amps x volts. Amps = Watts/240 volts.

If phase and neutral get reversed in a power line, electrical appliances may malfunction, and there is a risk of electrical shock to users. To rectify this issue, you must immediately shut off the power supply and contact a qualified electrician to correct the wiring configuration. Reversing phase and neutral can be dangerous and should be addressed promptly to prevent any potential hazards.

When the capacitor kVAR rating is much larger than required, it can cause overcompensation in the power factor of the system, leading to an overvoltage condition. This can result in increased stress on the capacitor itself, as well as on other components in the system. It is important to properly size capacitors to avoid these issues.

To balance a wye system you have to find the wattage connected to each breaker on each of the three phase legs. Total the wattages of the three individual phases legs. The difference in wattage is the unbalanced load. Then is is just a matter of deciding which breaker load should be moved to another leg to try and make all three legs as equal as possible. Working with an off and on again load wattage is sometimes hard to do because at certain times some of the loads will not be on. You should be able to get close but never right on. The only time you will ever get a completely balanced load is if the load is three phase resistance heating.

According a chart by Cooper-Bussman, voltage from 3 to 10 milliamps is painful, but not dangerous. From 10 to 40 milliamps is what is called the "let go threshold". When you reach that threshold your muscles have convulsed so hard that you can not let go of the conductor.

A short circuit is when the current in a circuit flows directly from the live/phase conductor to the neutral conductor without passing through a load. This is dangerous because the amount of current in a circuit is determined by the resistance/impedance (assuming constant voltage). The resistance of the conductor is very low and this allows large amounts of current to flow which should operate the circuits protective device (fuse). In the absence of a protective device the current will cause the conuctor toheat up first producing fumes from burning insulation and eventually seting on fire.

A triac turns off when the current flowing through it drops below the holding current level. This typically occurs when the voltage across the triac falls below the minimum holding voltage required to keep it in the conducting state.

== Current and Power and Energy
== The unit used to measure the flow of electricity, or current, is the ampere (A). The unit to measure power is the watt (W). Energy is measured in Joules (J). Amperes are really a measure of a rate of electron flow (electrons per second), or equivalently, how much charge is passed per second (Coulombs per second). 1 A = 1 Coulomb per second, and 1 electron has a charge of 1.602 * 10-19 Coulombs.
Power is measure in watts. A watt is an amount of energy per second, or Joules per second (1 W = 1 J/s). The number of watts is for an electrical circuit given by the number of amperes times the voltage drop: 1 W = 1 V * 1 A.
A power company supplying electricity wants to know how much energy (that's Joules) you have used. How much power (that's Watts) you use changes during the day... you turn on the toaster or microwave, your power usage goes up, and at night, you power usage goes down. But the amount of energy you use is the sum of that averaged over time (more precisely, it is the integral of your power consumption, or the area under your power consumption curve).
Energy is measured in Joules (in SI units), but power companies use funny units of kilowatt hours (kW hr). Since a watt is just a joule per second (J/s), a kilowatt hour is a measure of energy. Here is how you convert:
1 kW hr = 1000 W hr = 1000 J/s hr = 1000 J/s * 3600 s = 3.6 * 106 J or 3.6 million Joules
The power company doesn't use Joules on your electricity bill because we use a lot of them... instead they use kilowatt hours... but that's just a bunch of Joules.

The ground ('earth'), because of its mass, is a reasonably-good conductor and is used as a 'reference' for a distribution transformer's neutral terminal. A ground fault ('earth fault') occurs when the line conductor from the distribution transformer makes accidental contact directly with the ground ('earth'). The resulting low-resistance earth path back to the transformer's neutral is such that the resulting ground-fault current('earth-fault current') will operate the transformer's overcurrent protection device (e.g. fuse).

To convert horsepower (hp) to kilowatts (kw), you can use the conversion factor of 0.746. Therefore, for a 100 hp motor, the power in kilowatts would be 100 hp * 0.746 = 74.6 kW.

lets say each outlet will take up to 15 amps.a toaster will usually be rated at 1200watts.at 120v.divide 120 into 1200 =10 amps.so if you had 2 toasters connected to the same outlet you would be using a total of 20 amps on a 15 amp circuit.this outlet would be overloaded.

The breaker should be legibly marked, or the line side will clip onto the bus bar, and the load side should have a termination screw of some kind for you to attach a wire to it.

Some bolt in breakers are not marked, the type you may use in a custom control cabinet and it can be confusing. When vertical mounting, always set the breaker so gravity would open the breaker. Attach the line side to the top lugs. Horizontal mounting, just make sure it is marked for the off position, use either end for load or line.

The typical order for a substance's transformation through phases is solid → liquid → gas. This sequence represents the heating process where a substance gains energy to break the bonds holding its particles together, eventually leading to a phase change.

fuse