+ Post New Thread
Results 1 to 5 of 5

16th November 2019, 15:58 #1
 Join Date
 Nov 2014
 Location
 Saudi Arabia
 Posts
 167
 Helped
 1 / 1
 Points
 1,663
 Level
 9
What are the names of these voltages for a 3ph fullwave controlled rectifier?
I ran through this chapter and reached this circuit which is fine and I solved the previous controlled 1ph circuits' examples and I understand the parameters of the different voltages, current, power factor ... etc.
But when I reached the 3ph controlled circuit with resistive load, I found different voltages that I couldn't find a source that explain them all. But I understand the rest of the measuring parameters.
This is the circuit:
This is the solution of the example:
I want to know what are the naming & difference between VL(m), Vphase & Vm?

Advertisement

16th November 2019, 17:27 #2
 Join Date
 Apr 2011
 Location
 Minneapolis, Minnesota, USA
 Posts
 13,053
 Helped
 2599 / 2599
 Points
 53,455
 Level
 56
Re: What are the names of these voltages for a 3ph fullwave controlled rectifier?
Hi  Your images navigate to an area of the All About Circuits website which requires an account. Please post again and upload each image to Edaboard as an attachment.
1 members found this post helpful.

Advertisement

16th November 2019, 17:41 #3
 Join Date
 Nov 2014
 Location
 Saudi Arabia
 Posts
 167
 Helped
 1 / 1
 Points
 1,663
 Level
 9

Advertisement

17th November 2019, 03:47 #4
 Join Date
 Jan 2019
 Posts
 474
 Helped
 121 / 121
 Points
 2,577
 Level
 11
Re: What are the names of these voltages for a 3ph fullwave controlled rectifier?
its been a while since i did power, so i;m a little rusty:
the coils are a transformer  provides isolation and step up or step down depending on turns ratios
as in single phase
the source on the left is a delta  that is, the three phases are 120 degrees part and the ends
of the three coils (1 per phase) are connected to look like an equilateral triangle
here is is drawn as a series connection that ends at the start
the voltages are line to line, or just line as they appear in the equations
the secondary is a y  usually drawn as an equilateral y
as in the drawing, the end of the coils tied together are called the neutral
the other ends are the phase voltages, a, b and c as labeled
VL(m) would be the maximum line voltage 
Vphase the phase voltage
Vm the maximum (phase) voltage
Im is the maximum current
Vo(avg) is the average output voltage 
the cos(20) is there because the conduction angle, where you turn the thyristers on, is 20 degrees
(or is it the angle the thyrister is on?)
Io(avg) is the average output current
Ith(m) is the maximum current in a thyrister
Ith(aveg) s the average currnt in a thyrister  they each conduct 1/3 of the time
part of this however seems off, as one needs a + thyrister (1, 3, 5) and a  thyrister (4, 6, 2) on at the same time to conduct
and they have to turn on in the correct sequence
1 and 4 (for example) cannot be on at the same time
1 and 6 are on for 1/2 the conduction time of 1 and 1 and 2 are on for the other 1/2 of the conduction time of 1
1 members found this post helpful.

17th November 2019, 19:06 #5
 Join Date
 Nov 2014
 Location
 Saudi Arabia
 Posts
 167
 Helped
 1 / 1
 Points
 1,663
 Level
 9
Re: What are the names of these voltages for a 3ph fullwave controlled rectifier?
what you think is rusty is gold to me :)
the coils are a transformer  provides isolation and step up or step down depending on turns ratios
as in single phase
the source on the left is a delta  that is, the three phases are 120 degrees part and the ends
of the three coils (1 per phase) are connected to look like an equilateral triangle
here is is drawn as a series connection that ends at the start
the voltages are line to line, or just line as they appear in the equationsthe secondary is a y  usually drawn as an equilateral y
as in the drawing, the end of the coils tied together are called the neutral
the other ends are the phase voltages, a, b and c as labeled
VL(m) would be the maximum line voltage 
Vphase the phase voltage
Vm the maximum (phase) voltage
the cos(20) is there because the conduction angle, where you turn the thyristers on, is 20 degrees
(or is it the angle the thyrister is on?)
Im is the maximum current
Vo(avg) is the average output voltage 
Io(avg) is the average output current
Ith(m) is the maximum current in a thyrister
Ith(aveg) s the average currnt in a thyrister  they each conduct 1/3 of the time
part of this however seems off, as one needs a + thyrister (1, 3, 5) and a  thyrister (4, 6, 2) on at the same time to conduct
and they have to turn on in the correct sequence
1 and 4 (for example) cannot be on at the same time
1 and 6 are on for 1/2 the conduction time of 1 and 1 and 2 are on for the other 1/2 of the conduction time of 1
+ Post New Thread
Please login