Bridge Rectifier Help

[Baling Wire]

but, without success.  The numbers are: M8278909  U8234  This device is 1-3/8th inches square and 1/2 inches thick.  The built-on heatsink is 1/8th inch by 1-3/8th inch square.  I picked up 3 of these at a hamfest to use in my wind project.  Any help is appreciated!  I just realized that the "M" preceeding the 8278909 is actually the Motorola emblem.  Still could not find any thing?  Help!

BW

[Flux]

A picture might help. From your description even if it is a bridge rectifier it will be too small for other than a tiny mill. From the number I suspect it is not a bridge.

Buying things that you don't recognise is usually not a good idea unless they come at give away prices and even then you are tempted often to use something far from ideal because it is in the way waiting to be used.

The only hit I got on that number seemed to indicate that it was some sort of processor and your description of the heatsink makes me think that even if it is a bridge it will be automotive and intended for forced air cooling.

Flux

[dnix71]

The U8234 is one of a series of Motorola GSM cell phones.

[Baling Wire]

Thanks! gentleman.  Here is a pic.  http://www.otherpower.com/images/scimages/8205/unknown_bridge_rectifier.jpg

BW

[ghurd]

Probably rated at or above "25A", with a big fat heat sink and heat sink compound.

Meaning I would trust it to about 15A (I don't like the plastic type as well as the cast metal type).

I never saw anything like that rated too low for a 12V system.

I figure they make them, just I never saw one.

My bet is it is plenty for a 12V treadmill motor windmill, if you use both AC inputs, a heatsink and heat sink compound.

G-

[dnix71]

This may be close.

similar product here: http://gridchoice.com/catalog/bridge-rectifier-8278909-u8139-p-2505.html

maybe that part is no lionger made, but you could email that supplier to see about yours (the U8234)

[jimjjnn]

I think the U8139 and U8234 are Mfg date codes.

81 is year 39 is week. I believe both bridges shown are same part with same specifications.

Motorola has used that system for as long as I can remember.

[Flux]

Yes I also think the real number is the first one and the last one is a batch code.

I couldn't get a hit on the first number except for a processor and from the picture it is not that.I suspect it is an old device and not rated that high.

I would go with Ghurd and say use it up to 10A with a good heat sink. I wouldn't aim for higher.

Flux

[tecker]

IBM at powersupply at 200 watt I 'ts a King Kong part

[melder215]

PLease help.  I am trying to use bridge rectifiers on windmills that i am making.  But i can still read AC comming out of them.  All the ones i use.  Even new ones i buy.  It only reads when the multimeter leads are hooked up a certain way.  But not the other.  I thought i had a general understanding of these basic simple electronics.  But i'm stuck.  Should i be able to read AC on my meter.  The rectifiers are clearly marked.  AC   +

-    AC

or with symbols.  Why am i having this trouble? I've got three homemade windmills and an OLD AIR-X i am trying to salvage.  help.  

[Tritium]

It sounds like you are reading pulsing DC.

Thurmond

[ghurd]

I was about to suggest reading a very old thread, but you have alreay posted to it.

Your bridges are not marked in a normal way.

AC has no + or -.

Meters can be very confusing.

The meter should read some AC comming out of the bridges.

Possibly place a 100V 470uF or 1000uF capacitor on the bridge output.  Test the DC voltage of the capacitors.

Be very careful.  The voltage can be very high.

You supply no information about the three homemade windmills.

Much more information is needed to help you.

G-