What Size Capacitor For A 3 Ton Ac Unit

1. How to tell the capacitor size past looking at the mfg sticker.

   Hi all Hvac Warriors, I am currently taking industrial organisation and unfortunately my Intro to Refrigeration Class professor didn't teach much compared to my Math professor. All we practice in class is watch some Hvac video on YouTube and become to some website to review some CFC type I, II and Iii questions. I guess I am going become an A in the course and without much real knowledge.
   I just purchased the Fluke 116/323 multimeter kit and playing with my Ac unit of measurement outside. I found out the capacitor currently on the unit is the wrong or could exist correct size. I purchased the dwelling house new in 2005 and a few years later the Air-conditioning non bravado cold air. Luckily the unit still under warranty, so I called Bryant & Sons. He came and swapped out the blown capacitor and the AC work again.
   I still accept the blown capacitor in my garage and it said 30/5 uF. The one been replaced is 35/vii.5 uF. On the invoice the technician wrote replace 35/v uF Cap. I wait at the fan motor and the sticker said CAP 5/370v. So I assuming the 5uF is correct size for the fan. The capacitor on the unit of measurement now is 7.5uF so I guess the technician put in the wrong size capacitor.
   Can someone aid me learn how to find the capacitor size for the compressor and the fan motor. Since both capacitor been put in past Bryant & Sons and I don't trust them to phone call to clarify.
   Thanks.

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2. The fan label will signal the MFD for the fan. The label on the compressor will either indicate the proper MFD or the model will tell your supplier what capacitor it needs.

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   everyone would do information technology!

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   "And I've been banned twice. What of information technology? If you aren't getting banned once every three years, you aren't trying." Brian8383

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3. UA Local 32 retired every bit of Jan 2020

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4. call the manufacturer with the model and serial number of your unit. They will then tell yous what information technology needs.

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5. Although they replaced information technology with a slight bigger Mfd , its ok. I will draw a little less amps. You tin can go up a smidge , you merely tin can't go lower than 30/ 5

   BUT a smidge is it !

   You cannot go "also" big , like throw on a 45 / 7.5 , because in that location is a limit of how much you can cheat the numbers , because the curve actually gets worse.

   If information technology will make y'all feel amend , go a 30/5 , simply hang onto that 35 /7.5 for spare

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6. Cheers all for the quick reply. I am non to worry about the electric current capacitor in the unit

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   Last edited by beenthere; eleven-30-2015 at 06:54 PM. Reason: Resized pic

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7. OP - good for you to observe incorrect size capacitor, & getting to know how to use your meter!! Check the amp draw now & later you install the right size cap. How long has the incorrect cap been in use?? Will the incorrect size cap shorten the life of the condenser fan motor?? I am non sure how to tell what size cap is required. The lazy mode is to call the parts house.I am Thinking at that place is a math formula?? What yous-tube people have yous been watching?? Some you lot-tube video's are not good-incorrect communication. Proficient work & good learning exp - hope yous can get some correct straight answers!!

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8. Originally Posted by YingGiang

   Thanks all for the quick reply. I am not to worry nearly the electric current capacitor in the unit right now. Since it been in at that place for more than 5 years with no problem.
   I am more into the science behind the number. Attached picture is what I google and it showed how to calculate the capacitor size. Anyone ever try that method before? How accurate it is? It is the right formula?
   I will try it when the pelting articulate out hither.
   Thank you

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   Sent from my iPhone using Tapatalk

   Last edited by beenthere; eleven-30-2015 at 06:54 PM. Reason: Deleted over sized pic

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9. The formula shown on the page you posted is a way to verify how much effective capacitance is in the capacitor that is installed.

   IT DOES Not tell you which value capacitor is NEEDED.

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10. Please resize your pics before posting them, cheers.

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11. OP while you are waiting on the pelting check out - Sorry. Cartoon a line at youtube vids that can aid DIYers later down the road.

    Final edited by beenthere; xi-xxx-2015 at 07:01 PM. Reason: Removed link

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12. Lamentable. Drawing a line at youtube vids that can help DIYers later downwardly the route.

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13. The scientific discipline is basic math.
    E/IR, where R is used for reactance measured as Ω'south.
    R or Xc is institute past XC = 1/(two π ten f x C)
    f is frequency, and C is capacitance
    2pi represents a full sine wave in radians or 360� (your calculator shows this a RAD & DEG.)

    So, for given number of sine wave cycles per sec, a capacitor of a given value will be inversely proportionate to it's reactance.

    Let's intermission it down:
    1/(2π ten 60hz) =~0.002653
    We are using micro Farad value, so move the decimal 6 places to 2653.

    Now we take 2653 x C = Xc
    Well we know XC is representing Ω or R value
    We use our meter to go Due east & I.
    Now solve for R using Eastward/IR

    Now we know Ninety and 2653, so we solve for C.

    As Timebuilder stated, information technology doesn't tell you what cap is needed, it testify its live or electric current value.

    Last edited past mgenius33; 11-30-2015 at 10:47 PM.

    "The just truthful wisdom is in knowing you know nothing" Socrates
    

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14. Mail Likes - 1 Likes, 0 Dislikes

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15. This will tell yous what size run cap you demand.

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16. Originally Posted past mgenius33

    The science is bones math.
    Due east/IR, where R is used for reactance measured as Ω's.
    R or Ninety is found by XC = 1/(2 π x f x C)
    f is frequency, and C is capacitance
    2pi represents a full sine wave in radians or 360� (your calculator shows this a RAD & DEG.)

    So, for given number of sine moving ridge cycles per sec, a capacitor of a given value will be inversely proportionate to it's reactance.

    Allow's break it down:
    1/(2π ten 60hz) =~0.002653
    Nosotros are using micro Farad value, then move the decimal half-dozen places to 2653.

    At present we have

    XC= 1/C x 2653
    Well we know 90 is representing Ω or R value
    We use our meter to go Due east & I.
    Now solve for R using E/IR

    Now we know XC and 2653, so we solve for C.

    1/Xc x 2653 = C
    Another way to write it, integrating the 2 formulas
    I x 2653 / E = C

    As Timebuilder stated, it doesn't tell you what cap is needed, it prove its live or current value.

    Correction

    Terminal edited by mgenius33; 11-30-2015 at 11:38 PM.

    "The just truthful wisdom is in knowing you know zilch" Socrates
    

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17. Mail Likes - 1 Likes, 0 Dislikes

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18. A note for those who are saddened by the missing youtube videos. Don't be.

    Delight empathise that these videos are non well vetted technically or in terms of clearly understandable production values. Often, I observe videos that are incomplete, misleading, and only plain wrong and dangerous.

    So, immature HVAC techs, get your journeyman to review any videos that you believe are good, and allow him critique them with you.

    Soon, y'all will know more half the HVAC video producers on youtube.

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    ii Tim 3:16-17

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    Member, IAEI

    AOP Forum Rules:

    
    
    

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19. Thanks again everyone for the quick respond. I agreed that some youtube video are very terrible for educational purposes. I had a few videos that I like and ane of my favorite is from professor Ron Walker. Check him out he is very good.
    mgeius33: Cheers for tip and unfortunately it doesn't aid me on this case. Or Maybe I don't know how to solve information technology by the technic your showed above by going with the information on the sticker. The compressor sticker only show the model number h29b33uabca, 208/230v, ph 1, 60hz and LRA 61.
    lions_liar great app and somehow it didn't show the capacitor info when I keyed in the model number. Very weird!
    I google the compressor model and a few links said it need a 35uF. The original ane that fail was 30uF. Could it be the reason that it neglect prematurely?
    Thank you.

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20. Originally Posted by YingGiang

    . The compressor sticker only show the model number h29b33uabca, 208/230v, ph 1, 60hz and LRA 61.

    lions_liar cracking app and somehow it didn't show the capacitor info when I keyed in the model number. Very weird!

    I google the compressor model and a few links said it demand a 35uF. The original one that neglect was 30uF.

    The reason the Copeland app didn't work is considering you take a Bristol compressor.

    I have two different manuals for Bristol compressors and they are fifty-fifty contradictory on the capacitor this compressor uses. Ane says a forty mfd, and the other a 45 mfd capacitor.

    The latest publication (2012) shows the 45 mfd cap.

    Last edited by rundawg; 12-02-2015 at 08:46 AM. Reason: added info

    Instead of learning the tricks of the trade, learn the trade.

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21. I have typed in a bristol, and information technology came upwardly. And yep, t sometimes gives 2 values of run cap, it depends on which condenser the compressor is in.

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    "If you tin�t describe what you are doing as a process, you lot don�t know what you are doing." ~ Westward. Edwards Deming

    All those who wander..are not lost.

    Practise Non..mistake my kindness for weakness.

    The early bird may become the worm..but the 2d mouse gets the cheese.

    ---

22. Originally Posted by mgenius33

    The science is basic math.
    E/IR, where R is used for reactance measured every bit Ω'due south.
    R or Ninety is found by XC = 1/(2 π x f x C)
    f is frequency, and C is capacitance
    2pi represents a full sine wave in radians or 360� (your calculator shows this a RAD & DEG.)

    And so, for given number of sine wave cycles per sec, a capacitor of a given value will be inversely proportionate to it's reactance.

    Let's break it down:
    1/(2π ten 60hz) =~0.002653
    We are using micro Farad value, then motility the decimal 6 places to 2653.

    Now we have 2653 10 C = Xc
    Well we know Xc is representing Ω or R value
    Nosotros utilize our meter to get E & I.
    Now solve for R using Due east/IR

    Now we know 90 and 2653, so we solve for C.

    As Timebuilder stated, information technology doesn't tell you what cap is needed, it show its live or electric current value.

    If this is bones math I'm screwed. Guess this is why your a genius.

    You demand to put the phone downwardly and get back to work!

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What Size Capacitor For A 3 Ton Ac Unit,

Source: https://hvac-talk.com/vbb/threads/1845841-How-to-tell-the-capacitor-size-by-looking-at-the-mfg-sticker

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