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 - <500 KHz
66 dB (uV)
O
500 KHz - <5 MHz
60 dB (uV)
O
5 MHz - <30 MHz
60 dB (uV)
EMI/RFI Filters
MTE CORPORATION
11
RFI/EMI Filters
FCC Limits
O
500 KHz - <2 MHz
60 dB (uV)
O
2 MHz - <30 MHz
70 dB (uV)
EMI/RFI Filters
MTE CORPORATION
12
PWM Drive RFI Interference
W/O Filter
dB /
µVolts
W/Filter
10K
40K
100K 200K
350K
1M 2M
10M
20M
Frequency (KHz/MHz)
EMI/RFI Filters
MTE CORPORATION
13
MTE ”RF” Series
RFI/EMI Filters
O
UL Approved through 600 volts
O
CE (LVD) Marked (up to 600 volts)
O
O
O
O
All ratings STOCKED at MTE
Fingersafe terminals
3-phase (6 amps thru 330 amps)
1-phase (10, 16 and 20 amps)
EMI/RFI Filters
MTE CORPORATION
14
RFI/EMI Filter Selection
O
Install on VFD input only
Size for total RMS current:
O Select proper voltage rating
O
O
Connect in parallel for higher
current ratings
EMI/RFI Filters
MTE CORPORATION
15
MTE Gives You...
·
Delivery from stock
·
Availability of high current ratings
·
All standard voltages available
·
Lowest installed cost
·
High insertion loss
·
A global delivery system
EMI/RFI Filters
MTE CORPORATION
16
EMI/RFI Filters
MTE CORPORATION
17