Magnetic Chip Detector

[ClarAudrey]

Hello Everyone :)

I'm asking about the CFM56-3 engine but all responses are welcome!

Somebody please tell me...:{

How does the magnetic chip detector work?
Where does it get it's power from?

Where on the engine is the Air/Oil and Fuel/Oil Heat Exchangers located?

Lots of Thanks in advance...

Clara

[munster]

http://www.b737.org.uk/
is the site to look at.
mag chip detectors are basically removable magnets placed in the oil return lines to attract ferrous metal chips which would be an early indicator of impending failure, fuel oil heat exchanger is on the left side of the engine above the MEC, air oil exchanger is in the fan duct air flow.
check the site, there's loads of info

munster:ok:

[Riccardo]

There are two kinds. Chip detectors and chip collectors.

Chip Collectors are as Munster said - removable magnets which attract the ferrous material as the return oil flows across it. Inspected periodically for unwanted material.

Chip Detectors are also magnets but they have a gap in the magnetic tip which has +ve supply on one side and (usually) a ground signal on the other side. When a piece of metal bridges the gap it closes the detection circuit and flags up the appropriate message which can be an EICAS message, maintenance message, CWP caption or just a dolls eye on a maintenance panel, depending on aircraft type.

[mitzy69]

Debris on the MCD if the engine is new can be build debris as the engine is assembled and screws and nuts tightened down, so is normal.
Metal on the MCD after initial build debris has to be assessed as to quantity and size.
A nice big chip from a gear tooth is a problem, a few slithers can be carried on for a 100 hours and be assessed again.
Big companies would have a department which analyse the fines from MCD after each daily check and can predict when the engine would had to be changed as a thrust bearing or gear wheel is shedding metal.
Down the line the engineer would not have the lab or ability to analyse the type of metal on the magnet by its chemical make up, so can only guess.
Metal on MCD is covered in Maintenance manuals in ATA chapters 72 or79

[etienne.ar]

hey if u want i have a handout for gas turbine engine which includes chip detector...:)

[grounded27]

A quick wipe and it's business as usual! Jokeing aside, if you find anything more on the magnet than a small dab of fine metal (nothing that could break skin) an investigation and/or engine change is in order. Could be part of the gearbox, could be a main bearing (not good).