NEWS ARTICLE ARCHIVESBenefits of 3 Phase Power from Phase Changer
3-Phase Power - What's the point?
A Simple introduction to AC Power Batteries have a designated positive and negative end. When applied to a DC motor, swapping these two connections will change the direction the motor rotates. Most electronics, including the modern LED torch, are sensitive to this polarity and requires the correct connection for the equipment to work. The simple light globe does not care about polarity and will shine just as bright connected either way. If some kind of mechanical contrivance were to unplug a battery from a lamp circuit, reverse it and put it back again very fast, at say fifty times per second, the lamp would appear to remain steadily lit and we would have something approaching a 50 cycle (or Hertz), Single Phase AC (alternating current) power source. The energy we receive from the domestic power outlet resembles this reversing battery effect, except it runs at a higher 230 Volt level and it has very smooth changes in polarity.
Some Good and Bad points about Single Phase AC power The Single Phase AC supply is really versatile. It can be conveyed along long distances with relatively few losses on just two wires. Sometimes only one wire is needed if the Earth is being used as a return path. This makes it fine for lighting and electronic appliances in domestic households, but it still has a couple of issues. As the voltage passes from Positive to Negative, it must also pass through a zero voltage point. This means that there are instants in time when no energy is being delivered to the customer load. This is not a problem for small loads, but when trying to drive larger loads, such as electric motors, this effect can impact the energy levels reaching the equipment.
Another small limitation is that without the addition of a component called a capacitor, most types of Single Phase motors have difficulty in deciding which way to turn when first activated, or may not turn at all.
Introducing Three Phase Power
Usually 3-Phase power is delivered over three wires called the Delta format. These three wires are generally labeled L1, L2 and L3. Sometimes a fourth common or Neutral wire is added and this is described as the Star format.
Sounds complicated. Is it worth the extra effort? Apart from the higher voltages used, the real advantage to 3-Phase Power is in how electric motors perform. The staggered phasing arrangement instantly tells the motor which way to rotate, so complicated start capacitor stages are not needed. As the energy in a 3-Phase circuit is spread over all three connections, the peak start current is about half of the level needed for similar sized Single Phase motors. This means that there are fewer issues with power dips and flickering lights when larger motors are being started. Three Phase motors are cheaper to manufacture and are more efficient to operate than their single phase counterparts. All this adds up to many manufacturers of equipment like metalworking machines, car hoists and refrigeration systems actively use three phase motors in their designs. This pretty much forces the customer to install a 3-phase connection if they want their machine to work.
Getting Three Phase Power connected to your home or workshop
Is there an easy way to convert Single Phase to Three Phase Power? Whichever way you look at it, 3-Phase Power is a convention that will be with us for many years to come. Taking time to learn more about such systems is a sound investment for the future. |