SCR... main circuit of VFD

[powerjunx]

hello folks..
1.)what are the other solid state device used to protect the SCRs(silicon-controlled rectifier)? aside for surge protectors and diodes.
2.) what makes up the surge protectors, its operating characteristices and protection features to the SCRs?
3.) is surge protectors that is used in SCRs is the same with the surge protectors used in rotatry exciter of ac generator which is connected in parallel with the dc output?
4.)in SCR protections, How can we matched the rating of SCR with diodes? does we need to refer in operating characteristic of the SCR with its reverse voltage breakdown, so with the forward bias voltage of diodes?

any suggestions or recommendations for websites with regards to SCRs protection?

thank you very much..

regards
fbjavier

 

[cbarn24050]

Hi, i'm not sure exactly what you want to know here, scr protection comes in two sorts, 1 overvoltage, 2 overcurrent. Overcurrent is normaly done with fast fuses. Overvoltage is done either with voltage dependent resistors (MOV) which absorb the voltage pulse, or the voltage pulse is diverted into a capacitor, often via a diode, this energy is then dissapated in a resistor accros the cap.

 

[jbartos]

Suggestions to fbjavier (Electrical) Oct 6, 2002 marked ///\\hello folks..
1.)what are the other solid state device used to protect the SCRs(silicon-controlled rectifier)? aside for surge protectors and diodes.
///Potentially, thermal protection by solid state thermal detectors, solid state fuses, etc.\\ 2.) what makes up the surge protectors, its operating characteristices and protection features to the SCRs?
///Surge protectors have to dissipate energy of the surge pulse.\\\
3.) is surge protectors that is used in SCRs is the same with the surge protectors used in rotatry exciter of ac generator which is connected in parallel with the dc output?
///Most likely, it is not, although the intent of the surge protection is the same.\\ 4.)in SCR protections, How can we matched the rating of SCR with diodes?
///Current ratings, voltage ratings, ambient temp rating, etc.\\ does we need to refer in operating characteristic of the SCR with its reverse voltage breakdown, so with the forward bias voltage of diodes?
///It depends.\\ any suggestions or recommendations for websites with regards to SCRs protection?
///Visit:

http://www.intersil.com/data/an/an9/an9842/an9842.pdf

etc. for more info\\