What is this component?

[sherrilb]

My electronics education and experience go back to 1963-70. Vacuum tubes, high voltage power supplies,...

Please tell me what this component is. Other than knowing it is a diode (or reads like a diode when isolated from the other circuitry, I know nothing about it and need to replace another like it.

This is a part of bridge rectifier, I think. The module is an inverter, 220 vac single phase to 220 vac three phase.

Thanks in advance.

Sherril

 

[betwixt]

It is a MELF (Metal Ended Lead Frame) diode but there is no standard color coding for the bands on it I'm afraid. That makes it very difficult to positively identify unless it's function in the circuit can be established then manufacturers data searched for matching color bands.

Brian.

 

[sherrilb]

That is less than pristine from my point of view.

The manufacturer holds the board as proprietary and I can find no information for it other than a user's operating manual. Which I find a little amazing since the inverter has been around at least since 2001 which was when my lathe was manufactured.

That rant aside, I need a suitable replacement.

To give you an idea of my interest: I am not terrifically invested in the inverter since I have already bought a replacement; I am working on it to renew my interest in electronics so I suppose you could say it is a toy for me.

Does the Metal Ended Lead Frame diode have any attributes that are peculiar to it as a diode or can it be replaced with another type diode with roughly the same characteristics (that I can derive with a multimeter) more or less safely.

I think I mentioned in my original post that I believe the diode is a part of a bridge rectifier. The jpegs I have attached to this post are named "bottom..." and "top..." The bottom is where the diode I originally mentioned is located. (Right next the the pad I destroyed. I'm learning to solder pcb's.) The red line surrounds what I believe is the bridge rectifier.

Thanks again. I really appreciate your help.

Sherril

It is a MELF (Metal Ended Lead Frame) diode but there is no standard color coding for the bands on it I'm afraid. That makes it very difficult to positively identify unless it's function in the circuit can be established then manufacturers data searched for matching color bands.

Brian.

 

[betwixt]

The black 8-pin packages are T250V opto-coupled IGBT drivers and they appear to be connected between the multi-pin connector and the transistors on the heat sink. That means the diode is almost certainly part of a speed-up network and therefore probably a fast normal diode. I can't see how it can be part of a bridge rectifier. The circuitry on the top side and bottom side seem quite independent of each other and the output side rectifiers are probably the small black diodes at angles, they could however be part of a snubber network, its difficult to tell without tracing the tracks.

There is nothing special about MELF packages, they are like normal glass axial devices but with a disc at the end instead of a wire. It does allow better heat conduction from the junction but mostly it is just a sime way to make them surface mountable.

Brian.

 

[ruggb]

It definitely is not part of a bridge circuit. It is definitely not a power diode. I would go with a GP diode.