Need help on Capacitor wiring on single phase 220 with 3 capacitors

Thread Starter

ETowns

Joined Feb 12, 2022
5
First THANK YOU for any help on my situation. I have an old Air Compressor I am trying to get running again that was in disrepair when I got it. It has a 3 capacitor set up inside the electrical box on the Century Farm Duty motor model # 6-350079-03. One of the capacitors was missing out of it when I got it so I went ahead and replaced all of them with 3 new 1000/1200 MFD Caps which was what was in it. My dilemma is, How do the three caps wire to the motor Start and Run windings. I know one of the winding wires was hooked to the opposite tap on the incoming line cap. I also know that the other motor winding was connected to one tap on the top cap. I just do not know how the jumper wires connected all the caps together. At 39$ a pop, I do not want to let the smoke out of these new capacitors. Have I got them wired correctly in my picture? Thank you again for any help.
 

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MaxHeadRoom

Joined Jul 18, 2013
28,681
For a start, you would identify the separate start and run windings, What are the values of the capacitors?
What size is the motor? Does it have a centrifugal start winding switch?
 

Thread Starter

ETowns

Joined Feb 12, 2022
5
For a start, you would identify the separate start and run windings, What are the values of the capacitors?
What size is the motor? Does it have a centrifugal start winding switch?
I have the run winding and start winding figured out. It was number 6 as start and number 7 as run on the wire numbers that was attached to the remaining 2 of 3 old Caps. The motor is a 5 HP Farm duty 1720 RPM and the caps were replaced with the same value that came out which was 1000/1200 MFD. Not for sure on the centrifugal start winding switch, short of taking the motor apart, what is the best way to check for it? I forgot to attach a picture of the motor tag information. Doing so now.
 

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MaxHeadRoom

Joined Jul 18, 2013
28,681
Normally the start winding is the higher resistance of the two, a high (1200uf?) Capacitive value is attached to this one, the other two could be in parallel for the lower resistance run winding
Typically the run capacitor is much smaller value.
 

Thread Starter

ETowns

Joined Feb 12, 2022
5
Normally the start winding is the higher resistance of the two, a high (1200uf?) Capacitive value is attached to this one, the other two could be in parallel for the lower resistance run winding
Typically the run capacitor is much smaller value.
All 3 were connected together in some configuration. This is how I guessed at how it was wired in this picture. Does this look like it will fly and not let any smoke out?
 

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MaxHeadRoom

Joined Jul 18, 2013
28,681
It doesn't add up if you have a start and run winding, those values in total would be large even for just start caps, but you normally would have a lower capacitor in circuit all the time with the start/run winding?
The low resistance run winding itself uses no caps and is connected across the supply. Normally, at least.
 

Thread Starter

ETowns

Joined Feb 12, 2022
5
It doesn't add up if you have a start and run winding, those values in total would be large even for just start caps, but you normally would have a lower capacitor in circuit all the time with the start/run winding?
The low resistance run winding itself uses no caps and is connected across the supply. Normally, at least.
That makes sense then especially if the motor does have a centrifugal switch. If I am following you correctly the run winding connects on the same terminal as L1 on Cap 1 so when the switch activates, and takes out the Run winding the motor runs on the power of L1 terminal on Cap 1. The point of the other Caps then is they run in a daisy chain with jumpers starting from terminal 2 of Cap 1 to terminal 1 on Cap 2 then from Cap 2's terminal 2 to Cap 3's terminal 1 and then to the Start winding which would be connected at terminal 2 of Cap 3 . I'm I close? Ha! Ha!
 
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