Difference between revisions of "EMI suppression cores"
From Granite Devices Knowledge Wiki
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[[File:Ferrirebeads.jpg|thumb|Snap-on ferrite cores]] | [[File:Ferrirebeads.jpg|thumb|Snap-on ferrite cores]] | ||
[[File:Ferritebead.jpg|thumb|Toroidal ferrite core]] | [[File:Ferritebead.jpg|thumb|Toroidal ferrite core]] | ||
| − | EMI suppression cores or ferrite cores are an efficient way to reduce high frequency interference from wiring. Running cables through a ferrite | + | EMI suppression cores or ferrite cores are an efficient way to reduce high frequency interference from wiring. Running cables through a ferrite cores is a recommended solution attempt if signal reliability or connection problems are encountered. |
==Selection== | ==Selection== | ||
For motor control applications it is recommended to get low to medium frequency ferrite cores for maximum efficiency. | For motor control applications it is recommended to get low to medium frequency ferrite cores for maximum efficiency. | ||
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===Application=== | ===Application=== | ||
[[File:Ferrite multiple turns.jpg|thumb|Turning cable 2-3 times through core or using multiple in series increases filtering performance.]] | [[File:Ferrite multiple turns.jpg|thumb|Turning cable 2-3 times through core or using multiple in series increases filtering performance.]] | ||
| + | [[File:Argon test stup closeup m.jpg|thumb|Correct installation of a core in 3 phase motor U,W and V wires and leaving PE wire out.]] | ||
Application tips: | Application tips: | ||
| − | * | + | *If possible, make 2-3 turns of cable through one core to maximize it's effectiveness |
*Place core close to interference source, not in the middle of the cable | *Place core close to interference source, not in the middle of the cable | ||
| + | |||
===With servo drives=== | ===With servo drives=== | ||
To solve an EMI problem its good to have selection of cores that can be tried on different cables. Most typical placement for cores: | To solve an EMI problem its good to have selection of cores that can be tried on different cables. Most typical placement for cores: | ||
| − | *Motor output cable (all motor wires through core but '''not''' earth conductor) | + | *Motor output cable (all motor wires through core but '''not''' earth conductor). However, if earth conductor is hard to separate, then feeding all wires through core is still better than nothing. |
*High voltage power supply cable (+ and - leads through core) | *High voltage power supply cable (+ and - leads through core) | ||
| − | *USB adapter | + | *USB adapter or other communication cables |
| − | * | + | *Control I/O cables |
*Encoder/feedback device cable | *Encoder/feedback device cable | ||
{{Tip| Don't run multiple different type of signals through single core. I.e. don't combine power supply and motor leads in one core. Doing so can make filtering worse than without cores.}} | {{Tip| Don't run multiple different type of signals through single core. I.e. don't combine power supply and motor leads in one core. Doing so can make filtering worse than without cores.}} | ||
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==See also== | ==See also== | ||
*[[Wikipedia:Ferrite bead]] | *[[Wikipedia:Ferrite bead]] | ||
| − | [[Category: | + | [[Category:Argon troubleshooting]] |
| − | [[Category: | + | [[Category:IONI troubleshooting]] |
| + | [[Category:VSD-E/XE troubleshooting]] | ||
[[Category:Glossary]] | [[Category:Glossary]] | ||
Latest revision as of 12:32, 12 February 2016
EMI suppression cores or ferrite cores are an efficient way to reduce high frequency interference from wiring. Running cables through a ferrite cores is a recommended solution attempt if signal reliability or connection problems are encountered.
Contents
Selection[edit | edit source]
For motor control applications it is recommended to get low to medium frequency ferrite cores for maximum efficiency.
- Preferred types
- Core material designed for low to medium frequency bands (attenuation between 1-300 MHz)
- Large enough to fit cable multiple rounds through it
- Avoid (might make things worse)
- Core material designed for high frequency bands (above 300 MHz)
- Inductor cores
- Iron powder cores
- Most ferrite & iron powder cores look same. If unsure about material properties, its most safe to purchase new low to medium frequency cores.
As example, take a look at Laird broadband and low frequency cores.
Where to find suitable cores[edit | edit source]
Ferrite cores are available from most electronic part distributors such as:
- Digikey
- Mouser
- Farnell
Some popular ferrite core brands:
- Laird-Signal Integrity Products
- Fair-Rite
Usage[edit | edit source]
Application[edit | edit source]
Application tips:
- If possible, make 2-3 turns of cable through one core to maximize it's effectiveness
- Place core close to interference source, not in the middle of the cable
With servo drives[edit | edit source]
To solve an EMI problem its good to have selection of cores that can be tried on different cables. Most typical placement for cores:
- Motor output cable (all motor wires through core but not earth conductor). However, if earth conductor is hard to separate, then feeding all wires through core is still better than nothing.
- High voltage power supply cable (+ and - leads through core)
- USB adapter or other communication cables
- Control I/O cables
- Encoder/feedback device cable
 | Don't run multiple different type of signals through single core. I.e. don't combine power supply and motor leads in one core. Doing so can make filtering worse than without cores. |
