Briefly explain how an alternating current transformer works and why they are so important to the world’s electrical power infrastructure.
Okay. You take a magnet and run it past a coil and you get electricity. You can also simply switch the direction of current (or pulse it) in order to create induction current in a coil. So. if you make a basic AC electromagnet with say. 100 loops of thick copper wiring, and put it next to another coil with say. 10,000 thinner wraps. The coil that gets the juice, will induce a current in the coil next to it. Conveniently, more wraps higher voltage lower amperage, and fewer wraps higher amperage lower voltage. So in the above scenario, under ideal circumstances, we would take a primary voltage off 100 volts 100 amps and turn it in to a stepped-up voltage of 10,000 volts at one amp. The reason this is important is that high voltage travels well over great distances. It is much easier to push the same juice much farther away from its source with very high VOLTAGE and low amps than it is to do it the other way. Amps cause heat, heat causes loss and damage to the carrier wire. Voltage just rides along on the surface of the wire with very little loss. So we step up for transport and back down for use when we are close enough to end-use that the losses are negligible.
Current transformers are used extensively in the power generating and distribution systems. A current transformer is a dough-nut shaped device, winding actually, that slips around the cable you wish to monitor. The primary of this device obviously has one winding. Current transformers are used in the protection of network to operate circuit breakers, metering devices, reverse power relays , all type of sequence relays, I could go on and on. The nice part about current relays is the use of them keeps extremely high voltages from being taken to the control section of the equipment, thereby protecting service personnel from being exposed to these high voltages. A common current relay used for this purpose is a 5 ampere output at the rated current flow through the cable being monitored. For instance a 100:5 ratio.
