Help me about rectifier

Thread Starter


Joined Apr 4, 2005
Hi... :) I'am new member from indonesia...

I have problem about Rectifier circuit... :(

my machine in my factory short circuit at rectifier
than type of rectifier is 15MA400 (37~45A 4000V)
But that rectifier build with series wiring 10 pcs
We searching at indonesian market cannot find...
but we find other type 15MA300 (37~45A 3000V)

My question is..
- Can I change original type with other type (15MA300) for wiring with 13pcs..??
- Can I joining 2 type rectifier on 1 wiring..??
- Can anyone help other type or other wiring for change my rectifier wiring set..??

thank you verymuch for your atention...

Engieering Dept Engine


Joined Jan 22, 2004

your best option is to replace that with the original specs and order it direct from the manufacturer. :)

the next option is to replace it with a lower voltage spec but of the same current rating. for the moment i can't say you can or cannot. we don't know at what voltage level is your rectifier rectifying. you see that 4000v is your breakdown voltage.

pls be specific with more infos so appropiate suggestions can be presented. we have great guys here that can help you out :)


Joined Jun 21, 2007
sorry i know this is slightly off topic but i am new to this forum and have not worked out how to start anew topic.

What i am after is the formula to calculate the output voltage of a polyphase rectifier.

Eg. I have a 3 phase PRI (415VRMS) supplied transformer @ 50Hz, and SEC output of 380VRMS on a DELTA Tap, and 380RMS on a STAR Tap.

This gives me 2 sets of 3 phases with a phase difference of 30degrees (if you impose the star winding over the delta).

Once (SCR) rectified there will be 12 pulses @ 220VRMS (311peak).

HOW DO I CALCULATE THE RMS recitiied voltage for this circuit (I understand there will be a small ripple voltage between waveforms.