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-   -   15/230v motor from 15amp? (https://www.askmehelpdesk.com/showthread.php?t=393164)

  • Sep 7, 2009, 06:13 PM
    KISS

    Well, that wasn't obvious in any of your posts. So, I guess you should have said I have a 115/230 motor which will start and rotate when not on my saw, but when I connect it to may saw the 15A breaker pops.

    So, we have a 1.5 HP/15 A motor...

    Running on 12 AWG and not too far from the panel. Something like under 25' or so?

    A saw should not have very little load on it when it starts.

    Ordinarily, I would say we have to figure out what size wire and CB and thermal characterisics are required for the breaker.

    I'm basically heading here: New pool pump trips breaker? [Archive] - DoItYourself.com Community Forums

    Given, the new information, I'd like to have:
    1. The distance from the breaker to the motor
    2. The panel model
    3. The breaker model that you used.

    For now, make sure that the pulleys in the saw spin free and if you have a 20 AMP breaker to substitute in the 15 AMP place, do it.

    Motors can draw as much as 5x their FLA current on start-up. A few things control tripping:

    1. The time-trip curve of the breaker
    2. The wire size
    3. The breaker size

    Depending on the duty-cycle and how often used, I might be inclined to use a single phase motor starter with overloads.

    I'll see what I can find out. You may have to upgrade wire size, breaker size or re-wire for 230.

    If you have 125 V in your shop then the FLA rating would increase by 125/115 or to at least 16.3 Amps.
  • Sep 7, 2009, 07:51 PM
    woodyGuy

    I thought it was understood that the motor and saw would run simultaneously.

    In either case, the panel is Square D, the breaker 15 AMP (unknown make), the wire is 14 AWG.

    I am trying to run it less than 15 feet from panel.

    The new question is: Should I still try to re-wire the motor or should I just add a 2P, 15AMP w/ 12AWG.

    I can also add a 1P, 20AMP in place of the current 1P, 15AMP and just run the 12AWG wire to the current GFIC outlet?
  • Sep 7, 2009, 09:03 PM
    KISS

    Technicly, the wiring needs to support the FLA (Full Load Amps) of the motor. 15A @ 115 V is not the same as 120 or 125 that you probably have in your shop, so 12 AWG would be the right size wire at 120 V. At 115V, 14 AWG would be fine.

    Since this is a motor on a dedicated circuit, and IF the breaker is of an instantaneous trip type, it can be up to 800% of the FLA and I believe 250% of the FLA if it's a delayed trip breaker.

    So, if you have a 20 A breaker and your using 14 AWG wire and if the FLA was 15A you would be OK. But 120/115*15 is bigger than 15, thus 12 AWG is technically needed.

    The NEC stipulates that only the motor be on the breaker for the above to be true.



    When you wire for a higher voltage, the current becomes LESS not more.

    240/230*7.5 =7.82 A; This is less than 15A, so 14 AWG is permissible.

    If the breaker was 15 A, it would be 15/7.82 or 192% which is below 800% which is OK. So is 20A is 255% which is less than 800%, so your fine.

    Your seeing a good reason for "motor starters" which have thermal overloads and/or electronically settable overloads. These don't respond to brief current spikes and the overcurrent protection can be tailored a bit more with fuses.
  • Sep 7, 2009, 10:23 PM
    hkstroud
    1 Attachment(s)

    KISS,

    This is what it appears you have or its replacement. Does not specify whether it is capacitor start/run or capacitor run. At this point I would guess that its capacitor run and has faulty capacitor. It is Lesson direct replacement for Delta motor number 62-042
  • Sep 7, 2009, 10:29 PM
    KISS

    That's where I was heading initially, but the motor runs not in the saw. Motors used in that application would be motor start cap.

    Now that you mentioned it, there is still a possibility that the cap could be bad.

    So, maybe he should try to turn the saw on after he gets the blade to move manually.

    The best guess, I still think is a breaker that trips too fast for the starting current.

    But, if the cap were leaky, then it would not be able to move the additional mass to start.
  • Sep 7, 2009, 10:30 PM
    KISS

    That's where I was heading initially, but the motor runs not in the saw. Motors used in that application would be motor start cap.

    Now that you mentioned it, there is still a possibility that the cap could be bad.

    So, maybe he should try to turn the saw on after he gets the blade to move manually.

    The best guess, I still think is a breaker that trips too fast for the starting current.

    But, if the cap were leaky, then it would not be able to move the additional mass to start.
  • Sep 7, 2009, 10:39 PM
    hkstroud

    I have been only half following the post. I guess I got the impression that the motor turns (probably not up to speed) but has no torque.
  • Sep 7, 2009, 10:41 PM
    woodyGuy

    That motor is different. Mine looks the same but with an extra box attached to the motor (including the reset switch o the side) and a separate switch to turn on/off.
  • Sep 7, 2009, 10:49 PM
    woodyGuy
    How would I know what voltage I have in the garage (no shop)?

    I wouldn't mind adding a 2P, 15AMP breaker w/ 12AWG & run it dedicated outlet (not sure what kind exactly) for the table saw motor.
    If this is what would work?

    I was trying to run it from different locations in my garage including from the GFIC outlet which I found out is a 1P, 15AMP w/ 14AWG.

    I either need to run it w/ bigger wire or I need to rewire the motor??
  • Sep 8, 2009, 08:55 AM
    KISS

    How about taking a pic of the inside of your breaker panel. Post using "Go advanced/manage attachments".
  • Sep 8, 2009, 08:56 AM
    hkstroud
    1 Attachment(s)

    Suggest you go to this site. Ask for correct wiring connections for 120V.

    http://www.leeson.com/leeson/contact...ke=viewContact
  • Sep 8, 2009, 09:52 AM
    woodyGuy
    3 Attachment(s)
    Here are some pics. I can upload more if needed.
    Attachment 24351


    Attachment 24353

    The breaker for garage is the lowest on left of the panel FYI.
  • Sep 8, 2009, 09:59 AM
    woodyGuy
    2 Attachment(s)
    Here are 2 more pics.

    Attachment 24354

    Attachment 24355
  • Sep 8, 2009, 10:45 AM
    hkstroud

    You have your wiring connections right there on the tag. Low voltage is 120V.
  • Sep 8, 2009, 10:55 AM
    woodyGuy

    True, but it doesn't change the fact that it 'trips' my breaker on the panel each time I plug it to any outlet in my garage.

    It doesn't 'trip' any breakers when I undo the belt, blade, etc. & run it direct to an outlet?

    Any thoughts or ideas on what to do? Thanks
  • Sep 8, 2009, 11:03 AM
    KISS

    Sure does. Looks like we were chasing a wild goose.

    I also assumed the garage had a sub-panel, which isn't the case either. The breaker likely isn't dedicated either.

    There is a 20 A breaker on the right bottom. Can you TEMPORARILY move the garage to that breaker and try to run the motor in the saw? If the wire won't reach, then pigtail it.
  • Sep 8, 2009, 11:43 AM
    woodyGuy

    No sub panel and no dedicated outlet.

    If I do that, the wire is still 14AWG on the 1P, 15AMP breaker from panel to GFIC outlet by moving the garage to that breaker as you say.

    Should I maybe 'swap' the 1P, 20AMP breaker (on the right bottom) with the 1P, 15AMP breaker (on the left bottom) instead?

    And then plug the saw to the GFIC outlet which is still 14AWG, but now it will have the 1P, 20AMP breaker to power it.
  • Sep 8, 2009, 12:31 PM
    KISS

    I think there is 6 in one and a half dozen in the other solution. Temporarily moving a single wire seems like a whole lot easier than switching two breakers.

    All I know is that it could be the capacitor on the motor, but your way to close to 15A for wiring at 120 V to not trip the breaker.

    With a motor of that size, ultimately a separate dedicated 240 circuit, 12 AWG, 20 A, with a single phase motor starter is the way to go.

    If you absolutely know that the motor is OK, then I'd say go the above route.
  • Sep 8, 2009, 12:58 PM
    KISS

    This is probably the cheapest electronic motor starter that I know of. PESWS-9V24AX-RM30

    Note: You set the FLA of the motor electronically. It's designed for 230 V and 8 AMPS and 1.5 HP.

    I can't look at the catalog page from my tethered connection.

    Usually, the motor starters from Square D that I've been used to are three phase, contain fuses for each phase, have electronic overload protection and have installed in it a 3 phase monitor with a restart delay. Expensive.
  • Sep 8, 2009, 01:08 PM
    KISS

    Here is the actual datasheet: http://www.weg.net/files/products/WE...re-english.pdf

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