Things to Know About Current Transformers
A current transformer only has one or a few number of turns as its primary winding. This primary winding can consist of simply a bus bar or conductor position through a central hole, or a coil of heavy-duty wire wound around core. At Midwest Current Transformer, we offer a wide range of high-voltage transformers to our customers.
The Arrangement of a Current Transformer
Due to the arrangement associated with this current transformer, it is often referred to as a series transformer. The primary winding which only has a maximum of a few turns is in series with the current conveying the conductor which is providing a load.
However, the secondary winding may consist of a large number of turns wound around a laminated core consisting of low loss magnetic material. With a large cross-sectional area of the core, the magnetic flux density developed is on the low side, utilizing a cross-sectional wire area that is smaller, depending on the quantity of current that must be stepped down as it attempts to output a constant current, separate from the connected load involved.
The secondary winding supplies a current either inter-resistive load or into a short circuit in the form of an ammeter until the voltage induced in the secondary is of sufficient quantity to cause failure due to excessive voltage breakdown or saturate the core.
The three standard types of current transformers are toroidal, wound, and bar.
Toroidal Current Transformer
These transformers do not have a primary winding. The line that conveys the current flowing in the network is threaded through hole or window in the current transformer. Some of these current transformers have a split core which enables it to be opened, installed, and closed without disconnection of the circuit to which these current transformers are connected.
Wound Current Transformer
The primary winding of this transformer is connected physically in series with the conductor that conveys the measured current flowing through the circuit. The secondary current’s magnitude corresponds with the turns ratio of the current transformer.
Bar-type Current Transformer
This current transformer utilizes the actual busbar or cable of the main circuit as its primary winding, which is equivalent to a single turn. These transformers are insulated completely from the high operating voltage of the system and are often bolted to the device conveying the current.