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I am sure this topic will get everyone all excited and riled up
The discussion here is NOT about whether these three Gensets can be converted or not
They can, as to the heads they have installed, which are 12 leads and pose no problems.
Sewerzuk used the parallel low zigzag
The other option, which is used on the 002A / 003A units, is the double delta
Marathon has a note on their configuration page
I know that the amount of power to be able to draw has caused major contention in this forum.
This is also NOT the topic of this post on how much power can be drawn after conversion.
The actual topic of this Post is based on our experience of repairing A11 static exciter's with Voltage regulators
Sewerzuk showed in his video the correct connection of the AC Voltage Supply to the A11
The problem, which I have never seen addressed any where and which is causing a problem, is the Boost Circuit of the A11
The boost circuit is powered by the 3 Current Transformers CT 4; CT 5 and CT 6
They connect internally in the A11 to a 3 Phase transformer T1, which then sums the ouput off all three phases together on the primary side of T1 by the means of the 6 Diodes CR 1 to CR 6 and connects on the secondary side as a single phase signal to Terminals 5 and 6 on the Voltage Regulator Board
This circuit works only correctly when the three Current Transformers are supplied with 3 Sine waves which are 120 degrees offset.
Solving advanced trigonometry and calculus problems are not the favorite past time activity of probably 99.9 % of our esteemed members of this Forum, based on my experience.
However, and as Sewezuk demonstrated in his Video with his Oscilloscope, he was able to change the Phase relations between L1 and L3 from normally 240 degrees in three phase configuration to the required 180 degree phase shift for 240 VAC single phase operation
This induced phase shift causes now a problem for T1 in the A11 as the resulting DC Voltages are different and to put it in layman terms, confuse the Boost Circuit of the Voltage Regulator Board as to the actual boost needed, to maintain the selected (Voltage Adjust Rheostat) output voltage of the generator.
In my opinion, the Double Delta Configuration in conjunction with the AVR and Current Transformer Setup of the 003A would be the better approach
The experienced "Gensetter" can see the similarities of the A11 and the Current Transformers in the 003A Scheme
Furthermore, two other units in the 004A, 005A and 006A are also affected by this conversion, as the Thermal Watt Converter (Transducer) A1 with CT 1 CT 2 and CT 3 is looking for pure 3 Phase power with 120 degree phase shift between phases, not just Voltage levels, and
this also affects the Overload Protection Circuit for the same reason
This is food for thought for our braniacs in this forum to find a proper solution
My suggestion:
Remove A11, Thermal Watt Converter A1 and every and anything what has to do with paralleling operations and load sharing, use a suitable 2 pole circuit breaker and a aftermarket AVR
The discussion here is NOT about whether these three Gensets can be converted or not
They can, as to the heads they have installed, which are 12 leads and pose no problems.
Sewerzuk used the parallel low zigzag
The other option, which is used on the 002A / 003A units, is the double delta
Marathon has a note on their configuration page
I know that the amount of power to be able to draw has caused major contention in this forum.
This is also NOT the topic of this post on how much power can be drawn after conversion.
The actual topic of this Post is based on our experience of repairing A11 static exciter's with Voltage regulators
Sewerzuk showed in his video the correct connection of the AC Voltage Supply to the A11
The problem, which I have never seen addressed any where and which is causing a problem, is the Boost Circuit of the A11
The boost circuit is powered by the 3 Current Transformers CT 4; CT 5 and CT 6
They connect internally in the A11 to a 3 Phase transformer T1, which then sums the ouput off all three phases together on the primary side of T1 by the means of the 6 Diodes CR 1 to CR 6 and connects on the secondary side as a single phase signal to Terminals 5 and 6 on the Voltage Regulator Board
This circuit works only correctly when the three Current Transformers are supplied with 3 Sine waves which are 120 degrees offset.
Solving advanced trigonometry and calculus problems are not the favorite past time activity of probably 99.9 % of our esteemed members of this Forum, based on my experience.
However, and as Sewezuk demonstrated in his Video with his Oscilloscope, he was able to change the Phase relations between L1 and L3 from normally 240 degrees in three phase configuration to the required 180 degree phase shift for 240 VAC single phase operation
This induced phase shift causes now a problem for T1 in the A11 as the resulting DC Voltages are different and to put it in layman terms, confuse the Boost Circuit of the Voltage Regulator Board as to the actual boost needed, to maintain the selected (Voltage Adjust Rheostat) output voltage of the generator.
In my opinion, the Double Delta Configuration in conjunction with the AVR and Current Transformer Setup of the 003A would be the better approach
The experienced "Gensetter" can see the similarities of the A11 and the Current Transformers in the 003A Scheme
Furthermore, two other units in the 004A, 005A and 006A are also affected by this conversion, as the Thermal Watt Converter (Transducer) A1 with CT 1 CT 2 and CT 3 is looking for pure 3 Phase power with 120 degree phase shift between phases, not just Voltage levels, and
this also affects the Overload Protection Circuit for the same reason
This is food for thought for our braniacs in this forum to find a proper solution
My suggestion:
Remove A11, Thermal Watt Converter A1 and every and anything what has to do with paralleling operations and load sharing, use a suitable 2 pole circuit breaker and a aftermarket AVR
