Residential HVAC tech has question - Page 3
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  1. #27
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    Jul 2001
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    Anderson,SC
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    MicahWes

    A induction start motor has no start capacitor. A split phase motor is a poor motor, it has two windings start and run. The only way a split phase motor can start is by a phase shift. On a induction start motor the start winding are of higher resistance, longer copper and smaller than the run windings. On start the start winding will pull higher amps(LRA) and cause phase shift.

    If you add a start capacitor it now becomes a capacitor start/induction run motor.

    Also Wes I have to disagree with you on:
    " Also, the "klixon" used with standard starting components is an overload, not a relay."

    The klixon is a switch(relay). Its job is to take the start winding out of the system. If the klixon fails the start winding will stay in the sys and the start winding will stay in locked rotor amp and overheat. The overload then will shut the motor down. Now how the klixon works is it heats up and stops passing voltage to the start winding.

    STUD

  2. #28
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    Apr 2012
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    winnipeg
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    a klixon is not a relay in my opinion...it is an overload
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  3. #29
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    Mar 2007
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    NW AR
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    Its an overload. Its located on common on the compressor. The relay is attached to start and run.

  4. #30
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    I don't know how y'all can say the klixon (brand name) is an overload. An overload is opened by heat (high amp) and can reset its self or have a manual reset. It’s a safety. I know of no relay that reset, it’s a switch; a switch is either open or closed, by external action. A safety is always in series with the load it is protecting. A relay (klixon) is not a safety, it is a switch that has the job of taking out the start windings, if you take the klixon out and put in a start cap with a relay, you still need the overload. Something needs to be in series to protect the compressor.
    I am a res HVAC tech our compressor have an internal overload. The domestic refrigerator I was working on has an overload with one end to common (120 VAC) and other pushed onto common terminal. The relay had other wire (L1) to it and had two terminals pushed into start and run terminals. Its job is to take out the start windings, nothing more.
    The compressor would start and click the overload would open. The klixon (relay) was defective. I replaced the relay with a like part and worked fine.
    All I wanted to know is the refer techs thoughts on using a hard start cap instead of an OEM relay.

    STUD

  5. #31
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    Apr 2012
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    winnipeg
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    as long as it starts and does nor over draw amperage. go for it... I prefer oem parts
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  6. #32
    Join Date
    Oct 2009
    Location
    Raleigh, NC
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    HVAC/Stud, you aren't making much sense?

    Klixon is a brand name, but it has pretty much entered the lexicon to mean a bimetal switch that will open or close based on temperature. This temperature can be applied to the switch either externally (like in a roll out switch), or can be generated by current passing over the switch itself (single-phase compressor overload). On a small compressor in a home fridge there is usually one snap-disk style klixon overload on the common terminal. The start RELAY is attached to the start and run terminals. The relay alone deals with applying and disconnecting the start winding. The overload will interrupt common if it's disk overheats due to excessive current from either winding passing across it. It has nothing to do with dropping out the start winding.

    A 3 in 1 Relay/overload/capacitor IS A PTC START DEVICE!

    There is no such thing as an "induction start induction run motor". All single-phase motors designed to run on alternating current are induction motors (if they don't have brushes or slip rings). There are basically three kinds of single-phase A/C motors a technician traditionally encounters: shaded pole, capacitor start, and capacitor run (PSC).

  7. #33
    Join Date
    Mar 2007
    Location
    NW AR
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    Quote Originally Posted by HVAC/Stud View Post
    I don't know how y'all can say the klixon (brand name) is an overload. An overload is opened by heat (high amp) and can reset its self or have a manual reset. It’s a safety. I know of no relay that reset, it’s a switch; a switch is either open or closed, by external action. A safety is always in series with the load it is protecting. A relay (klixon) is not a safety, it is a switch that has the job of taking out the start windings, if you take the klixon out and put in a start cap with a relay, you still need the overload. Something needs to be in series to protect the compressor.
    I am a res HVAC tech our compressor have an internal overload. The domestic refrigerator I was working on has an overload with one end to common (120 VAC) and other pushed onto common terminal. The relay had other wire (L1) to it and had two terminals pushed into start and run terminals. Its job is to take out the start windings, nothing more.
    The compressor would start and click the overload would open. The klixon (relay) was defective. I replaced the relay with a like part and worked fine.
    All I wanted to know is the refer techs thoughts on using a hard start cap instead of an OEM relay.

    STUD
    I understand what your saying but I still have to disagree. Klixon is a brand name and is often stamped on both the overload and relay but almost always the overload.

    The overload is connected to the common terminal on the compressor. Like has been said, it opens on high current or temperature. Yes, it is a switch.

    The relay is connected to start and run on the compressor. It is what drops the start windings out. Yes, it is a switch of sorts as well.

    The 2 prong "switch" you put on start and run is the relay, not the overload.

    Most residential compressors are not internally protected, hence the need for the external overload.

  8. #34
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    Apr 2012
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    winnipeg
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    i am holding an overload in my hand ....it says klixon on it...what does that ell you...
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  9. #35
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    Nov 2006
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    Quote Originally Posted by timebuilder View Post
    I'm not able to find a sheet that reveals this information. My supply house said it's a relay.

    Can you give me a link to something?
    Something?
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  10. #36
    Join Date
    Jul 2001
    Location
    Anderson,SC
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    OK

    Y'all win. Thanks for the disscussion.


    STUD

  11. #37
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    Quote Originally Posted by timebuilder View Post
    Something?
    Heres one taken apart. Start capac on left, relay in the middle, which is attached to the overload on the right:
    Attached Images Attached Images  

  12. #38
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    Jul 2001
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    Anderson,SC
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    MicahWes, do a web search of induction start/induction run motors.
    It is a split phase (start and run windings) motor. It will not start with out phase shift. Its use is low HP, low torque conditions, doesn't need a start or run cap. Low cost motor.

    I'll add this, the motor I was working on, had a overload (bimetal) "YES".
    It had a device(relay,switch,PTC,klixon, ect) to take the start winding out,"YES".

    I can replace both with a hard start cap that has overload and relay if I don't have the OEM part"YES". If I have the OEM part I should use it"YES".

    Do I know everything "NO".

    Klixon is brand name. It is a overload and relay.

    Thanks for the advice and sharing your thoughts, I think we all share a love for HVACR.

    STUD

  13. #39
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    Oct 2009
    Location
    Raleigh, NC
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    My point is, all single phase ac motors are induction motors. They are all induction start, they are all induction run (unless they have commutators). Perhaps this is just a syntax disagreement.

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