vdmmedia
Plastic
- Joined
- Mar 29, 2003
- Location
- Athens, Georgia USA
In looking at the 'integrated' phase convertor design, there are both 'run' and 'start' capacitors listed. I realize that the 'start' capacitor is to produce a kick to get the idler motor started and the 'run' capacitor produces the phase shift necessary to manufacture the third phase.
But, are they actually the same (physical) design or are they two different constructions. Are they different from other types of capacitors which list their voltage rating a VDC instead of VAC.
In other words, "what's da deal here"?
If one were to build a large converter (say 30hp), is there a rule of thumb (or maybe an equation) for the value of the capacitors on a converter of this size running on 220V or on 440V.
Since a 30hp converter would have a rather large inrush (about 5 times the running current, I'm told) this would most certainly suck my residential neighborhood voltage down (and make me justifiabably unpopular). Would it be practical to clutch connect a 5hp single-phase motor to bring the idler up to near speed before powering the idler. It would then seem that the 'start' capacitor circuit could be done away with in this case simplifying the converter while at the same time reducing the inrush problem.
Also, are far as motors go, is the rotational speed of the motor significant? There are motors available in about 1170 rpm, 1800 rpm and 3600 rpm flavors. Does the rotating mass of the armature provide a 'flywheel' effect?
Questions, questions, questions...
Thanks in advance!
John
vdmmedia
But, are they actually the same (physical) design or are they two different constructions. Are they different from other types of capacitors which list their voltage rating a VDC instead of VAC.
In other words, "what's da deal here"?
If one were to build a large converter (say 30hp), is there a rule of thumb (or maybe an equation) for the value of the capacitors on a converter of this size running on 220V or on 440V.
Since a 30hp converter would have a rather large inrush (about 5 times the running current, I'm told) this would most certainly suck my residential neighborhood voltage down (and make me justifiabably unpopular). Would it be practical to clutch connect a 5hp single-phase motor to bring the idler up to near speed before powering the idler. It would then seem that the 'start' capacitor circuit could be done away with in this case simplifying the converter while at the same time reducing the inrush problem.
Also, are far as motors go, is the rotational speed of the motor significant? There are motors available in about 1170 rpm, 1800 rpm and 3600 rpm flavors. Does the rotating mass of the armature provide a 'flywheel' effect?
Questions, questions, questions...
Thanks in advance!
John
vdmmedia