Expert Council Q&A for 2-29-24 – Epi-3456 — 1 Comment

  1. Some input on the “soft start” for freezer question.
    I did not look up the product you and the expert council member we’re talking about but when you said $300 I thought I better write this to give 2 possible less expensive options:
    Which one of these you use depends on the type compressor motor you have.
    If you have a permanent split capacitor (PSC) to could add a “hard start kit” that consists of a start capacitor and a relay that takes the start capacitor out of the circuit after the compressor motor starts. Subco SPP-6 (my best recollection of the p#) is a two wire hook up. You simply put it in parallel with the run capacitor.
    Option 2: if you’re compressor is a split phase and already has a start capacitor (usually about the size of a C or D sell battery, black plastic) I would off check the capacitor microfarad to make sure they match its rating plus or minus the percentage. If it did not, I would, of course replace it. if it did, I would consider sizing it up 20%, maybe 25.
    Slim third option If the unit is old enough to have a start relay that is usually a rectangular plastic box 2 x 2 by one or so you would need too much higher skill set to replace that with a modern relay and a start capacitor.
    If you are interested in why this would work:
    In an inductive circuit (a motor is an inductive load) current sine wave lags behind the voltage side wave. This is a major reason for the high current in rush when you start a motor.
    In a capacitive circuit, the current sine wave precedes the voltage sine wave so when you add a start capacitor, it pushes them back together or closer together, allowing the compressor to start easier.
    PS considering the Subco is probably less than $30 and separate start capacitor replacement or upsize is probably less than $10. This is an economical avenue to pursue, assuming you have some electrical skills.