EMI/RFI Filters - MTE Corp

EMI/RFI Filters

 EMI Sources  EMC Standards  Solutions

EMI/RFI Filters

MTE CORPORATION

1

Capacitive Coupled Noise Current from Unshielded Phase Conductor of VFD

EMI/RFI Filters

MTE CORPORATION

2

Power Electronics can cause Conducted Electromagnetic Interference Problems

Power Switching Devices Cause EMI O

O O

Improvements in static switching devices have led to higher speeds Higher speed devices generate more EMI The problem: Common mode high frequency noise

I = c dv/dt EMI/RFI Filters

MTE CORPORATION

3

RFI/EMI Filter Applications • Adjustable Speed Drives ƒ Computers

ƒ Radio Controls

ƒ Automatic Lighting

ƒ Overhead Cranes

ƒ Telecommunications

ƒ AM Radio Equipment

ƒ Laboratory Equipment

ƒ TVs and Monitors

ƒ Factory Automation

ƒ Energy Mgt Systems

EMI/RFI Filters

MTE CORPORATION

4

Adjustable Speed Drives

Conducted Electromagnetic Interference Problems

Drive EMI Affects: O

Communication Links

O

Control Signals

O

Encoder Feedback

O

Programmable Controllers

O

Remote I/O

O

Sensors

O

Vision Systems EMI/RFI Filters

MTE CORPORATION

5

MTE RFI/EMI Filters block high frequency electrical noise

VFD

Parasitic Capacitance

noise “RF3” RFI/EMI filter EMI/RFI Filters

MTE CORPORATION

6

RFI / EMI FILTERS O

O

O

O

Help meet EMC directive Solve high frequency interference problems Have minimal panel space requirements RFI filter installed base over 15,000

EMI/RFI Filters

MTE CORPORATION

7

EMI Mitigation O

Wiring Practices – Shield power cables – Separate power and control

O

EMI/RFI Filter

O

Motor sine wave filter

EMI/RFI Filters

MTE CORPORATION

8

RFI/EMI Filter Insertion Loss

O

I.L. (dB) = 20 Log10 Vout/Vin

O

50 ohm source; 50 ohm load

O

Useful for comparison

O

Does not predict actual results

EMI/RFI Filters

MTE CORPORATION

9

MTE “RF” Series Filters Typical Common Mode Insertion Loss

EMI/RFI Filters

O

100 KHz

> 60 dB (uV)

O

150 KHz

> 70 dB (uV)

O

1 MHz

> 70 dB (uV)

O

10 MHz

> 40 dB (uV)

MTE CORPORATION

10

European (CE) RFI/EMI Filter Requirements EMC Directive Limits O

150 KHz -