Circuit published here is a dual stage EMI filter. EMI Filters are widely used in applications such as Appliances, Military systems, Aerospace systems , SMPS, VFD drives, AC Servo drives, Energy Management Systems, Computers, Factory Automation Equipment, Industrial Equipment, Medical Equipment, Automotive Battery Charger.
The EMI circuit normally consists of passive components, including capacitors and common mode inductors, connected together to form LC circuits.
The common mode inductor(s) allow DC or low frequency currents to pass through, while blocking the harmful unwanted high frequency currents. The capacitors provide a low impedance path to divert the high frequency noise away from the input of the filter, either back into the device, or into the ground connection. In addition to assisting to meet EMI regulations, the filter also has to meet safety standards.
The inductor temperature rise is measured and for mains operation, the minimum electrical spacing between line, neutral and ground are controlled. This reduces the risk of fire and electrical shock.
Note : Project has been design for multipupose, few components can be omited or mount as per application requirmnet, R1 NTC, R3 MOV, R2 resistors are optional. Value of inductors and capacitors can be selected as per power requirment.
- CN1 AC 100V to 250V AC Input Single Phase
- Maximum Load current up to 10Amps
- CN2 AC Output
Components
- Capacitor C4, C5, C6, C7 : 1K PF 1KV ( 1000V)
- Capacitor C1, C2, C3 : 0.47uF 270V AC X2
- R1 NTC : 10D-20 ( 20MM NTC) for Inrush Current Protection
- Common Mode Inductor ( Choke) : T1, T2 : 1MH 10Amps
- R3 Metal Oxide Veristor Optional
- F1 Fuse holder and Glass fuse 10Amps
Line bypass capacitors C4, C5, C6, C7 (Y-capacitor) Suppresses common mode noise
Common mode choke coil T1, T2 Suppresses common mode noise
R3 MOV Optional Can be selected as per application requirement
R2 Optional Not Used
R1 NTC to protect inrush current ( Optional Can be directly short using jumper wire)
