What is the difference between single phase and three phase generators?
To understand this, we can use a lightbulb as an example. Our homes are connected to alternating current electrical supply, so our house lights use alternating. The concept of phases in power generation only applies to alternating current; batteries deliver direct current, so the concept of phases is not applicable to direct current. So, our example does not apply to our battery powered flashlights. Only think of the overhead lights, lamps, and other appliances that are receiving power from either wall sockets of your home’s electrical supply.
Let’s Start with Single Phase Generators.
Generators work by spinning a magnet next to some wire, “generating” electricity. A gas motor powers a crankshaft. The crankshaft spins just like in your car; instead of a tire at the end, there is a magnet.
Magnets have a magnetic field arranged around its north and south poles. The force of the magnetic field causes electrons to move. When you put a magnetic field next to a copper wire, the electrons within the wire will move in a direction according to the orientation of the magnetic field. Moving electrons create a current, causing a bulb to light up.
The magnetic field is strong at the north and south poles. Between the poles (imagine at the east and west points) the magnetic field is weak. Remember that the magnet next to the wire in our generator is spinning. The wire will have strong current when closest to the north pole, no current when the “east pole” spins closest, a strong current next to south pole, and no current when the “west pole” spins closest. This alternating of strong and weak currents means that your light bulb will be bright, then dark, bright again, and then dark again. In fact, each of the lightbulbs in your house is going light, dark, light, dark 60 times per second, a frequency of 60 Hz. This is practically unnoticeable, such that single phase generators are ideal for powering most residences.
Three-phase Generators Offer Solutions for Industrial Applications.
Such is the problem of the single-phase generator. It delivers a relatively inconsistent supply of electrical power. This does not matter in residential homes; no one can notice their light bulbs flickering, and all of the appliances you use aren’t affected by this inconsistency, either.
Commercial and industrial equipment do require consistent electrical supply, however. Take an elevator as an example. This requires a lot of electrical input to operate, and it needs this consistency in order to rise and fall smoothly. A single-phase generator would give you a bumpy ride, vibrating at a frequency of 60 Hz. The three-phase generator is used to make sure you are comfortable and safe.
A single-phase generator has one magnet and one wire. Three-phase generators have three wires arranged with even spacing around one spinning magnet. As the first wire is experiencing a weak magnetic pull (meaning a weak electrical current), the second wire gets the full force of the magnet (resulting in a strong current). As the magnet spins and the second wire feels a weaker pull, the third wire is now positioned to receive the full force of the magnet.
The strong current from one wire compensates for the weak currents in the other two as the magnet spins, resulting in a more consistent electrical power supply. For our elevator example, the elevator would be vibrating three times less frequently, and the consistency ensures your safety. Much better.
Allied Rental Company supplies a variety of generators to suit your individual needs, including all-in-one single and three phase portable generators.