If the protection relay and CT installed for away, then it is advised to install 1A CT rather than 5A CT. Because of lower amps it will reduce the losses on the cable.
p = i^2.R
Current overload from whatever circuit draws current from the transformer? Proper fusing of its supply might protect a transformer from this cause. Or it could have developed a shorted turn fault because the insulation on a winding got old and perished? Or maybe the transformer got damaged if the appliance it is mounted in was dropped?
In a transformer with a turns ratio equal to 1, the primary current comprises the reflected secondary current plus the magnetizing current necessary to sustain the "back EMF developed across the mutual inductance coupling the primary winding to the secondary. Therefore the primary current is always greater than the secondary current in a transformer with a turns ratio equal to 1. This should be evident by applying Kirchhoff's Current Law to the central node of the "T-equivalent" model of a transformer.
'CT' is used to designate current transformers, and 'PT' is used to designate potential transformers. A current transformer provides a ratio of primary current to the secondary. A potential transformer provides a ratio of primary voltage to the secondary. A power transformer (step up or step down) resembles a PT more than a CT.
Because its measured in kilo volt amps which is the actual reflection of current flowing through the windings. if kw were used as a rating, then it would have to be stated at some power factor
Current Transformer- Instrument transformer used for measure high current. it hasless and thin turns in primary and more and thick turns in secondary.Potential transformer- Instrument transformer used for measure high voltage. it has more and thin turns in primary and less and thick turns in secondary.CommentUnfortunately, the original answer has got things the wrong way around for the CT! A current transformer's primary has a thicker conductor than its secondary.
A transformer has a rating that is usually expressed in KVA. This is approximately a wattage rating. It is not dangerous but it can be the cause of some concern. An appliance has a set current that is draws. This current times the voltage is the appliance's wattage. The same goes for the transformer. It only has a certain capacity to supply a specific current that is governed by its KVA (watts). Driving the transformer beyond its rated capacity tends to heat the transformer beyond its working temperature. If left in this over current draw the transformer's windings insulation will break down and the windings will short circuit. This is usually the end of a working transformer. So short answer, more watts (amps) from appliance equals burned out transformer.
You can buy a transformer that will output 12 volts DC at just about any electronics or department store. You will need to check the amperage as well to make sure that the transformer can handle the current draw, but for a radio this should not be that high (it's okay for the transformer to be rated for MORE amps than the radio draws).
A transformer can be used to change the voltage to an appliance. The voltage rating of the transformer should be right for the voltages used, and the current rating of the transformer should not be less than the current drawn by the equipment.
Current overload from whatever circuit draws current from the transformer? Proper fusing of its supply might protect a transformer from this cause. Or it could have developed a shorted turn fault because the insulation on a winding got old and perished? Or maybe the transformer got damaged if the appliance it is mounted in was dropped?
Yes. Yes, you can replace a transformer with one that has a higher current rating. The load on the transformer should be less than 200mA because presumably that is what the circuit was designed for. Since the current through the transformer should be less than 200mA, the 500mA transformer will not be damaged. The opposite is not true. You should not replace a 200mA rated transformer with a 100mA transformer, for example. If the current exceeds 100mA, the transformer could fry.
In a transformer with a turns ratio equal to 1, the primary current comprises the reflected secondary current plus the magnetizing current necessary to sustain the "back EMF developed across the mutual inductance coupling the primary winding to the secondary. Therefore the primary current is always greater than the secondary current in a transformer with a turns ratio equal to 1. This should be evident by applying Kirchhoff's Current Law to the central node of the "T-equivalent" model of a transformer.
Yes
'CT' is used to designate current transformers, and 'PT' is used to designate potential transformers. A current transformer provides a ratio of primary current to the secondary. A potential transformer provides a ratio of primary voltage to the secondary. A power transformer (step up or step down) resembles a PT more than a CT.
Because its measured in kilo volt amps which is the actual reflection of current flowing through the windings. if kw were used as a rating, then it would have to be stated at some power factor
Current Transformer- Instrument transformer used for measure high current. it hasless and thin turns in primary and more and thick turns in secondary.Potential transformer- Instrument transformer used for measure high voltage. it has more and thin turns in primary and less and thick turns in secondary.CommentUnfortunately, the original answer has got things the wrong way around for the CT! A current transformer's primary has a thicker conductor than its secondary.
No load current, in a transformer for example, is the current necessary for exciting the transformer. If you wish to keep it energized, and you need to keep it energized at full voltage, there is nothing you can do to reduce this other than replace the transformer with one that has lower no load current. If you are referring to a different piece of equipment, you may need to specify what you are meaning by "no load current".
This refers to the electric current in amps. There is no definition of what constitutes a low current, but in electronics it might refer to less than 1 mA, while in domestic power supply it might mean less than 5 amps.