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3 Phase motor starter for a 1 phase motor (FNG)

Discussion in 'Power Electronics' started by outlawspeeder, Dec 10, 2020.

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  1. outlawspeeder

    outlawspeeder

    5
    0
    Dec 10, 2020
    If this is in the wrong spot please let me know.

    I am looking for a hand or rewiring the controls for a 3 phase motor to a one phase motor. I am a home machine shop guy normally but I figure like the forums I use, people like to help each other.

    Below is a pic of a CR 106 B1. It was used to start a 3 phase motor and to protect the motor. Is there a way to use this to power a 1 phase motor. I plan on using 220. The power switch is a push button on and off. The old motor is a 3 phase 3/4 hp and the new motor is 1 phase 3/4 hp. Is there a better way?

    I can't find a wiring schematic for to use this for 3 phase let a lone 1 phase and the cover panel is missing. The wires inside was removed before I got it. I can play and figure it out but I don't want to let the magic blue smoke out of it.

    Yes I know I can use a VFD, phase-o-matic, rotary phase converter.... But I have the motor.

    Thanks



    upload_2020-12-9_21-23-39.png

    https://www.google.com/url?sa=t&rct...0and%201.pdf&usg=AOvVaw33lU7ucXoda6DE4VayoJHA
     
  2. Bluejets

    Bluejets

    4,424
    938
    Oct 5, 2014
    Why would you need a starter for a single phase motor of that size?
    Just plug in and turn on.
     
    Harald Kapp likes this.
  3. outlawspeeder

    outlawspeeder

    5
    0
    Dec 10, 2020
    Does the starter (CR 106) provide protection to the motor? Does the motor need protection? It is being used in a medium size band saw.
     
  4. Minder

    Minder

    3,033
    641
    Apr 24, 2015
    Normally when using a 3ph contactor for a 1ph motor it is normal for the live conductor to be looped out of the bottom of the O/L and through the next contact input, IOW poplate the three entries and exits.
    M.
     
  5. Tha fios agaibh

    Tha fios agaibh

    2,115
    713
    Aug 11, 2014
    I would loop together 3 contacts on top and connect it to line (mains) voltage and then tie motor load to the bottom contacts under the heater elements.

    You only need one contact, but since a 1 phase motor will draw more current than the 3 phase motor i would bridge the contacts. You'll probably need to change original heater elements on the starter to a higher current (heat#) to suit your new motor or it will trip the overload relay under a heavy load.
    20201211_081436.jpg
     
  6. Minder

    Minder

    3,033
    641
    Apr 24, 2015
  7. Bluejets

    Bluejets

    4,424
    938
    Oct 5, 2014
    Still say it's not necessary but if the Op needs control via a control circuit, say for a control isolator such as emergency stop, or a foot switch or whatever, then one would need to know the voltage of the control.
    If it is originally derived from the 3 phase i.e. 415v then forget it.
    If there was a neutral fed in originally on the 3 phase, then ok.
    But then there is the overload unit which may not be within the range as they do vary depending on whether a star or delta wind.
    Either way, the single phase would come normally with their own internal thermal overload.
    All depends on many aspects of the actual motor.
     
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