All gensets using Mecc alte alternator, have rotary rectifiers (including generator diode), checking and maintaining this part will help stabilize the output voltage and ensure the ability to operate properly motion of alternator. Today, TTTT will show you about the bridge rectifier circuit of the Mecc Alte according to the article below.

Common problem when generator diode in bridge rectifier fails?

When the generator operates at in the beginning, voltage differences are larger than normal. It might caused by fault in one of diode bridge.

The diodes are part of generator bridge rectifier, which usually located at the end of the generator 

Mecc Alte alternator bridge rectifier types and positions.

The alternator bridge rectifier is located at the tail end of the bearing, on the same side as the AVR regulator box. After removing the protective cover, we will see the generator diode TTTT. Each alternator has a total of 6 Diodes.

DiodeBáo giá

For the Series of alternators from ECP3, ECP28, ECP32, ECP34 and ECO38 (capacity below 400kVA) will use Diodes T30, and Series of alternators from ECO40, ECO43 and ECO46 (capacity above 400kVA) will use Diodes T18, detailed description can be seen below:

T18 rotary rectifier                                                                T30 rotary rectifier


Each rectifier bridge alternator will have diodes, each diode will have 2 poles: red + and black – , mounted on a heatsink machined aluminum plate.

Reference: Auto voltage regulator

Reference: Mecc Alte generator parts

How to check and replace an alternator diode?

Noted: You should check when Mecc Alte generator is not working and you need use a multimeter.

Only one end of the diode allows current to pass; When we use the black wire of the multimeter to touch the red end of the Diode and the red wire to touch the radiator plate of the rectifier, the meter does not sound. It’s a diode that works fine with no problems. Perform operation with all 6 diodes.

If one diode fails, the entire diode should be replaced to avoid future failure.

Above is all about how to replace an alternator diode. Good luck.



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