7/11/2013 7:06 AM  
Posts: 235 Rating: (52) 
Dear frenz In ac drive there is drive module(Rectifire unit) for converting ac to dc voltage ok. My question is when its convert ac to dc why the dc voltage is 1.35times hire(step up) then the ac voltage.how its done. 
7/11/2013 7:31 AM  
Joined: 3/21/2006 Last visit: 7/26/2024 Posts: 10228 Rating: (1181) 
ABC of Drivesthere you couuld find a lot of useful information. 
7/11/2013 8:05 AM  
Posts: 235 Rating: (52) 
its too long where is it? 
7/11/2013 2:55 PM  
Joined: 10/11/2006 Last visit: 8/1/2024 Posts: 5883 Rating: (801)

Hello, the DC voltage is the arithmetic average. There is no electrical component or something that sets up the voltage. There are only 6 diodes (uncontrolled rectifier). In this link (page 3 and 4) you find the voltage diagram and the detailedcalculation of the arithmetic average: 
With best regards, 

7/11/2013 4:07 PM  
Joined: 7/8/2009 Last visit: 8/5/2024 Posts: 1976 Rating: (477) 
Its a very basic of rectifier  not specific for drives In addition to above nice document from TechTeam here is what wiki have to say https://en.wikipedia.org/wiki/Rectifier If still want simpler, try google and you will find a lot of help Devesh Vithani 
I dont Like people driving Fast, thats the reason I overtake them ;) 

7/14/2013 7:03 AM  
Joined: 10/19/2012 Last visit: 4/17/2022 Posts: 315 Rating: (9) 
The (mean) average voltage of AC is zero, because it alternates equally from +ve/ve. At any point in time it's +this or that, neither of these things are much use for anything. RMS being "Root Mean Square" is a math way of getting something meaningful out  you square the voltage so that ve becomes +ve (2 x 2 = +4), then average it and squareroot it (root +4 = 2). As AC is "lumpy" the peak voltages at the top of the sinewave are above the RMS average, and if you're not applying heavy load the rectified DC voltage is closer to these peaks than the RMS (math' for AC) value. 
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