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Why common mode choke is used?
Common mode choke coils are used to suppress common mode noise. This type of coil is produced by winding the signal or supply wires one ferrite core. Common mode choke coils work as a simple wire against differential mode current (signal), while they work as an inductor against common mode current (noise).
What is choke and its application?
In electronics, a choke is an inductor used to block higher-frequency alternating currents while passing direct current (DC) and lower-frequencies alternating current (AC) in an electrical circuit.
Why choke is used in VFD?
A choke placed between the drive and the motor also helps to reduce electromagnetic interference from the cables and the possibility of reflected waves. Both “choke” and “reactor” are commonly used terms for an inductive device placed after the input diodes (between the input rectifier and the DC bus link) in a VFD.
What is the function of choke?
What do you mean by common mode choke?
A common mode choke is an electrical filter that blocks high frequency noise common to two or more data or power lines while allowing the desired DC or low-frequency signal to pass. Common mode (CM) noise current is typically radiated from sources such as unwanted radio signals, unshielded electronics, inverters and motors.
What are Coilcraft common mode chokes used for?
Coilcraft LPD, MSD and PFD Families are low profile, miniature footprint common mode chokes that can be used to attenuate common mode noise or differential mode noise in both data and power line applications. Coilcraft low-cost, high performance surface mount power line common mode chokes come in a variety of sizes and packages.
How does saturation occur in a common mode choke?
The magnetic field due to the supply current is compensated inside a common mode ferrite core, but the stray inductance (around 1% of nominal) still leads to saturation at the peak current. The effect of saturation is mainly felt at the bottom end of the spectrum, where a loss of attenuation of more than 10dB can occur.
What happens when a choke passes its rated current?
The problem is made worse when the choke is passing its rated current, because winding losses lead to heating. At higher temperatures, saturation is reached at lower values of flux density, translating to lower attenuation values.