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When secondary coil is open there is no current in the primary coil WHY?
Wiki User
∙ 11y ago
I am assuming the question is about the power / distribution transformer and not the current transformer.
The primary current is a function of load connected on secondary. With the open secondary, there is no load, no current, it is open circuit. Hence no primary current.
However there is always some small amount of no load current in the primary winding.
Wiki User
∙ 11y ago
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Why the CT secondary short circuited?
Current transformers produce a ratio of primary current in the secondary. If the secondary of a CT is open circuited, and primary current is flowing, the CT will try to push that same ratio of current through the secondary open circuit. This causes secondary voltage to climb until it the secondary open circuit flashes over. This can often damage the CT.
Does transformers draw any current when secondary is open?
-Yes, the transformer draw current when secondary open. Because, the secondary of the transformer is open, the primary draws only no-load current, which will have some copper loss. Therefore, power is no longer transferred from primary to secondary in this approximation, and negligible current goes through the secondary windings.Some current will flow through the primary as well as secondary to magnetise the core to maintain the internet relaship between primary &secondary winding as the winding consist of small resistance it is neglected practically hence the current will at at no load also which is small in magnitude compared to the full load current.Thta is why we says that transformer draws current when secondary is open.
How does ignition coil transform low voltage to high voltage?
A: The coil is really a transformer. The 12 enter the coils and charges with current as the point opens up this charge is released as energy about 100 mw. This release is transformed to hi voltage at the secondary by a primary to secondary turn ratio like 1:3333 more or less. Since the primary is open the same ratio will feed the primary that is why we see ringing and the point have capacitor to protect from false firing. <<>> The coil is a transformer, but we know that DC will not work with a transformer. A supply of 12 volts DC is applied to the coil's primary winding. In series with this coil is a set of breaker points. These points are used to interrupt the 12 volt supply from the coil. When the 12 volt supply is interrupted, the magnetic field around the primary winding collapses. This collapsing field induces a voltage into the secondary coil of the transformer. The secondary coil has many more turns that the primary coil and the voltage induced will be in the 10,000 to 15,000 volt range. This high voltage is needed to make the voltage jump across the air gap in the spark plug.
Why open circuit test show only core losses?
With the secondary not supplying any load, there is no secondary current and the primary current will be a low-value magnetising current. So, the copper losses, (I2R) will be insignificant.
Why current transformer secondary side short circuit?
A current transformer (or CT) is constructed in a specific way so as to step down the current in a high power circuit for measuring or protective relaying purposes. Typically, it will have a toroidal-shaped iron core with the secondary windings wrapped around it. the primary "winding" is usually the conductor of the main power system passing directly through the hole in the center of the CT. As a result of this construction, if the secondary windings are left open, a very large flux can develop, resulting in damage to the CT and possibly even the other equipment it is attached to. As such, if the CT is not going to be used, its secondary windings need to be shorted.
Why the CT secondary short circuited?
Current transformers produce a ratio of primary current in the secondary. If the secondary of a CT is open circuited, and primary current is flowing, the CT will try to push that same ratio of current through the secondary open circuit. This causes secondary voltage to climb until it the secondary open circuit flashes over. This can often damage the CT.
When the transformer is connected to the power source the secondary current is 0 what is the possible fault in the transformer?
A secondary current of 0 would suggest to me that the secondary circuit is open. A normally operating circuit with zero current flow would be very unusual. No load in secondary circuit. No secondary current can also be attributed to the primary power source open or an open primary winding.
Does transformers draw any current when secondary is open?
-Yes, the transformer draw current when secondary open. Because, the secondary of the transformer is open, the primary draws only no-load current, which will have some copper loss. Therefore, power is no longer transferred from primary to secondary in this approximation, and negligible current goes through the secondary windings.Some current will flow through the primary as well as secondary to magnetise the core to maintain the internet relaship between primary &secondary winding as the winding consist of small resistance it is neglected practically hence the current will at at no load also which is small in magnitude compared to the full load current.Thta is why we says that transformer draws current when secondary is open.
What is the function of the primary current when the secondary winding of the transformer is open?
When the secondary of a transformer is opened, there is no longer any load on the transformer. There will be some current flowing in the primary winding, which is needed to induce the voltage in the secondary. This primary current is referred to as the "no load" current, and is indicative of the core losses in the transformer.
Why secondary coil of ct is short?
A CT attempts to push a specific ratio of primary current through the secondary. If the secondary is open circuited, the resistance across the secondary will be very large. Following Ohm's law, V = I*R, so the secondary voltage will become very large, and will arc across the open, or damage the CT, or both.
What happens when secondary of the transformer is open?
The secondary winding leakage inductance limits the current during a short. It seems that the current through the primary is limited by winding resistance and leakage resistance when the secondary is shorted.
How can you reduce the voltage in current transformer when it is open?
You never ever ever ever under any condition open the secondary when primary current is flowing.
Why should the secondary of a voltage transformer not be short circuited?
A voltage transformer takes a primary voltage and steps it down to a smaller secondary voltage. This type of transformer will attempt to keep the secondary voltage at a specific ratio of the primary voltage. If you short it, massive current flow in the secondary is required to do this. For a similar reason a CT should never be open circuited - because it attempts to push a specific ratio of primary current through the secondary. If you open circuit the secondary, it takes a massive voltage on the secondary to accomplish this.
Why does transformer draws current when secondary is kept open?
A: If the transformer is connected to a power input of course it will draw current. The primary is a long wire it has own resistance wrap around an iron core. Of course there will be primary current whether there is a load on the secondary or not.
Why secondry of current transformer should not be open?
A current transformer will always attempt to push a ratio of the primary current through the secondary. So if there is primary current flowing, and you open circuit the secondary, the CT will attempt to build up voltage to the point where the correct amount of secondary current can flow through the open circuit (meaning you will get an arc). If it succeeds, you'll have a bright light, and some melted copper, and a very startled person who was unfortunate enough to open circuit the CT. This high voltage can also damage or ruin the CT.
How does ignition coil transform low voltage to high voltage?
A: The coil is really a transformer. The 12 enter the coils and charges with current as the point opens up this charge is released as energy about 100 mw. This release is transformed to hi voltage at the secondary by a primary to secondary turn ratio like 1:3333 more or less. Since the primary is open the same ratio will feed the primary that is why we see ringing and the point have capacitor to protect from false firing. <<>> The coil is a transformer, but we know that DC will not work with a transformer. A supply of 12 volts DC is applied to the coil's primary winding. In series with this coil is a set of breaker points. These points are used to interrupt the 12 volt supply from the coil. When the 12 volt supply is interrupted, the magnetic field around the primary winding collapses. This collapsing field induces a voltage into the secondary coil of the transformer. The secondary coil has many more turns that the primary coil and the voltage induced will be in the 10,000 to 15,000 volt range. This high voltage is needed to make the voltage jump across the air gap in the spark plug.
Why open circuit test show only core losses?
With the secondary not supplying any load, there is no secondary current and the primary current will be a low-value magnetising current. So, the copper losses, (I2R) will be insignificant.
