Input On My Pieced Together Rpc

in effect you will be switching start caps and run caps in and out of the circuit if things are working correctly.
you shouldn't use run caps and starts caps at the same time.
when the start caps charge is introduced there should be no run caps in the motor circuit until the start caps are out of the circuit
 
Ulma Doctor said:
in effect you will be switching start caps and run caps in and out of the circuit if things are working correctly.
you shouldn't use run caps and starts caps at the same time.
when the start caps charge is introduced there should be no run caps in the motor circuit until the start caps are out of the circuit
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Ahhh. I get it. I need to re work my run circuit as I have those powering up right away at the same time as the start caps.


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At startup all the caps are connected in parallel. When the motor reaches running speed the relay disconnects the start caps which then discarge through the shunt resistor. There is no opportunity for anything I'd call dumping. It's just like a capacitor-start capacitor-run single-phase motor.
 
i agree, as long as the caps are in parallel the will be no issues-
making series connections will not work as intended
 
Alrighty guys, got this thing preliminary up and running. everything seems to be working as it should. Its essentially wired exactly how my drawings looked. I think i need to add some more Run caps still. unloaded Im getting l1-l2=235v l1-l3=224v l2-l3=216v. Light load 230v,208v,208v. I either am too low on run capacitors or i need to add a jumper line from a real leg to L3 as Im only connected through run caps. and of course the start caps when those are in play.

She gets to full speed quicker than I can let go of the start button so I'm confident in my start system.

as far as run cap values, is the "10-15uf per idler HP" per bank or total? Im running 45uf between l1-l3 and 50uf between l2-l3. Maybe I need to get closer to the 15uf per HP and have around 75 per bank.

Curious to hear your guys feedback.IMG_2612.JPGIMG_2611.JPG
 
John Hasler said:
No, no. Don't do that. Your motor is *generating* L3. You're within 10% and the voltages are balanced. Leave it alone.
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:) I immediately tried adding that jumper after posting and she wouldn't even start. Learned that doesn't work.

So am I crazy to think I could get it more balanced? My math says I'm 9.5%. Adding a few more uf's in small doses won't get me closer to possibly 5%?


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