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  1. #1
    Join Date
    Feb 2007
    Location
    Canberra
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    101

    Default CTJ-680 thicknesser tripping circuit

    Hi All.
    I bought a second hand carbatec thicknesser and I can't get it to run. It is a CTJ-680 15 amps/3hp.
    My shed has 20 amp cabling (with 10 amp plugs) and 20 amp circuit breakers.
    The machine throws the CB on startup. Apparently the motor draws 70amps on startup without a load (no belts).
    The electric motor people said I need to get a circuit breaker that is not as sensitive to that initial peak of current.
    Does anyone know whether that is a thing?
    Obviously I want to run the machine and whatever I do needs to be safe.
    Does anyone know where to get that sort of advice? The electrician I talked to couldn't get his head around it.
    I might mention that this is after fixing the oil leak and changing the bearings and the engagement pinion so any help to get the machine to turn would be a mercy.
    Thanks
    Steve

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  3. #2
    Join Date
    Dec 2005
    Location
    South Australia
    Posts
    3,304

    Default

    As you have been advised you may need a different circuit breaker, there also may be a electrical fault some where, did you witness the machine running before you purchased it ?
    If you onyly have "10 amp plugs" how are you running a 15 amp machine.

  4. #3
    Join Date
    Feb 2007
    Location
    Canberra
    Posts
    101

    Default

    Thanks China. The previous owner ran it using a lead with a 10 amp male plug and a 15amp female plug that bridges between the 15 amp plug on the machine itself. I had the motor tested by Delta Electrical and they said there's nothing wrong with it. The wiring in my shed it new and I have no probs running my 1.5hp dusty and my 2hp TS. Each on different circuits though. If I need a circuit breaker I need a sparkie to install it that "gets" the issue and can offer a safe solution.

  5. #4
    Join Date
    Jul 2015
    Location
    Hunter Valley
    Age
    51
    Posts
    817

    Default

    You really ought to have a 15 amp circuit wired in if you're going to run this piece of kit - and before I get in trouble, it really ought to be done by a licensed electrician. Yes, I know the previous owner was able to "cheat" by using a 10 to 15 amp converter lead, but we don't know what cabling was behind the wall, nor what his switchboard had in it.

    Some SawStop owners will also be familiar with startup current issues, the SawStop PCS and ICS are known to cause this issue too.

    If memory serves, a "D Curve" circuit breaker is what you want - it allows a longer startup time for the initial current draw. You could have one installed whilst having the 15 amp circuit run

    Now, at the risk of sounding rude, I'm not an electrician, I've gained the knowledge I post here from reading, and speaking to my own electrician in the process of building my new workshop. I wouldn't think this sort of stuff would be difficult for a qualified electrician to figure out, perhaps seeking the opinion of another electrician might prove beneficial?

  6. #5
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    23,191

    Default

    [QUOTE=Midnight Man;2135902] If memory serves, a "D Curve" circuit breaker is what you want/QUOTE]

    Yep.
    And Yep to getting its own 15A GPO and its own cable/circuit/breaker.

  7. #6
    Join Date
    Feb 2007
    Location
    Canberra
    Posts
    101

    Default

    Thanks BoBL

    I still don't understand why the 20amp cable is not up to the job. But I guess it all boils down to what an electrician will certify.
    I'll talk to another electrician but it sounds like running another cable is where I'll end up. Frustrating as I though I would have things covered when I had the new shed wired with 2x 20amps.

    [QUOTE=BobL;2135905]
    Quote Originally Posted by Midnight Man View Post
    If memory serves, a "D Curve" circuit breaker is what you want/QUOTE]

    Yep.
    And Yep to getting its own 15A GPO and its own cable/circuit/breaker.

  8. #7
    Join Date
    Aug 2003
    Location
    Conder, ACT
    Age
    72
    Posts
    5,799

    Default

    DISCLAIMER

    No liability is accepted by UBeaut or the Wood Working Forum's administrators
    or moderators for advice offered by members posting replies
    or asking questions regarding electrical work.
    We strongly advise contacting a Licensed Tradeperson for all electrical work.
    WARNING

    Information supplied within posts is not to be considered as detailed formal instructions to complete a task.
    Members following such information do so at their own risk

  9. #8
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    23,191

    Default

    Quote Originally Posted by SteveMcM View Post
    I still don't understand why the 20amp cable is not up to the job. But I guess it all boils down to what an electrician will certify.
    unfortunately in matters naught whether it’s capable of coping or not, these are the regs as I know them.

  10. #9
    Join Date
    Jan 2014
    Location
    Sydney Upper North Shore
    Posts
    3,170

    Default

    I had my shed rewired with a 40a dedicated circuit from the house switch board to a separate board in the shed.
    i have 3 X 15A power points around the shed, each off their own dedicated circuit breaker. He also ran 2 X 10A circuits, one to the front and shed RHS and one to the back and the LHS; each circuit has a dedicated breaker. Each circuit has a number of power points off it.

  11. #10
    Join Date
    Feb 2007
    Location
    Canberra
    Posts
    101

    Default

    Sure.
    There's another thing I came across, which was getting a 15A outlet put into the meter box and plugging the machine into that.
    It is pretty close and might be easier than new runs of cable.
    Any thoughts?

    Quote Originally Posted by BobL View Post
    unfortunately in matters naught whether itís capable of coping or not, these are the regs as I know them.

  12. #11
    Join Date
    Oct 2007
    Location
    Alexandra Vic
    Age
    64
    Posts
    2,530

    Default

    Hi Steve,

    Regarding the initial issue, you have two circuits with 20A breakers and an unspecified number of double 10A outlets on each circuit. These outlets are connected in a daisy chain, i.e. there is a cable running from the breaker to the fist outlet in the chain, then another running from the first to the second, etc until you get to the end of the chain. At each outlet, the wires of the feeder cable are twisted with the corresponding wires of the following cable to the next outlet, fed into the appropriate terminal of the outlet and locked in place with the terminal screw.

    For moderate loads, each of these cable junctions creates a minor voltage drop that generally does not affect the operation of the device being used. However, these voltage drops are cumulative and as you get further along the chain from the breaker, the effect is more obvious. Then if you plug your 3HP thicky in at the far end of the chain and turn it on, with the extreme start currents involved, the voltage drop through all the cable junctions can become extreme. The motor will attempt to start, but may take 3 to four times longer than it normally would because of the reduced voltage available. A normal C curve breaker reacts quickly to an overload situation, and if the start current is being drawn for an extended period (more than a couple of mains cycles), it would trip out, which is exactly what it is intended to do, protect the electrical system and building from protracted overloads.

    The D curve breakers are designed to be more tolerant to overload conditions and do not trip as quickly as the C curve ones, however they may not solve the issue on their own if the voltage drop across all of the cable junctions is substantial. I am not up with all of the modern day wiring regs, but it was fairly common years ago that 15A outlets would be a dedicated circuit with a 20A or higher rated breaker with appropriate curve for intended use, powering an oversize cable directly to a single outlet, so there are no twisted joints in the cable to contribute to excessive voltage drops.

    You also do not mention how many dual outlets there are on the existing circuits, or how many other items were operating from them at the time that you attempted to run the thicky. However items that people often regard as fairly insignificant, like the shop stereo, battery chargers for shop tools, etc can also draw enough trouble to contribute to the issue. The suggested solution of a new breaker and 15A outlet at or very close to the board is a good one, provided you have sufficient supply to the board for this to work. If you have a sparky do this for you, I would suggest that you have them replace the power cord on the thicky with one of suitable size and rating to run from where you want the thicky to where the new outlet is placed, so that you do not need to use undersize or overlength extension cords to power the unit in service, and can eliminate an extra plug and socket and their voltage drop contributions.
    I used to be an engineer, I'm not an engineer any more, but on the really good days I can remember when I was.

  13. #12
    Join Date
    Feb 2007
    Location
    Canberra
    Posts
    101

    Default

    Thanks. I'm not really sure how the various outlets are chained. It is good to know that these voltage drops occur. I have a sparky coming tomorrow that will sort this thing out for me. Fortunately, I remembered that I got a cable run in the wall for a car charger if I ever needed it. So I think it is 32amp and he is going to wire that up. Thanks for the suggestion about the cable on the actual machine. I will also get him to wire a longer cable onto the machine because it is only about 1m long. A car charger is a way of in the future and I can cross that bridge when I come to it.
    Steve

    Quote Originally Posted by malb View Post
    Hi Steve,

    Regarding the initial issue, you have two circuits with 20A breakers and an unspecified number of double 10A outlets on each circuit. These outlets are connected in a daisy chain, i.e. there is a cable running from the breaker to the fist outlet in the chain, then another running from the first to the second, etc until you get to the end of the chain. At each outlet, the wires of the feeder cable are twisted with the corresponding wires of the following cable to the next outlet, fed into the appropriate terminal of the outlet and locked in place with the terminal screw.

    For moderate loads, each of these cable junctions creates a minor voltage drop that generally does not affect the operation of the device being used. However, these voltage drops are cumulative and as you get further along the chain from the breaker, the effect is more obvious. Then if you plug your 3HP thicky in at the far end of the chain and turn it on, with the extreme start currents involved, the voltage drop through all the cable junctions can become extreme. The motor will attempt to start, but may take 3 to four times longer than it normally would because of the reduced voltage available. A normal C curve breaker reacts quickly to an overload situation, and if the start current is being drawn for an extended period (more than a couple of mains cycles), it would trip out, which is exactly what it is intended to do, protect the electrical system and building from protracted overloads.

    The D curve breakers are designed to be more tolerant to overload conditions and do not trip as quickly as the C curve ones, however they may not solve the issue on their own if the voltage drop across all of the cable junctions is substantial. I am not up with all of the modern day wiring regs, but it was fairly common years ago that 15A outlets would be a dedicated circuit with a 20A or higher rated breaker with appropriate curve for intended use, powering an oversize cable directly to a single outlet, so there are no twisted joints in the cable to contribute to excessive voltage drops.

    You also do not mention how many dual outlets there are on the existing circuits, or how many other items were operating from them at the time that you attempted to run the thicky. However items that people often regard as fairly insignificant, like the shop stereo, battery chargers for shop tools, etc can also draw enough trouble to contribute to the issue. The suggested solution of a new breaker and 15A outlet at or very close to the board is a good one, provided you have sufficient supply to the board for this to work. If you have a sparky do this for you, I would suggest that you have them replace the power cord on the thicky with one of suitable size and rating to run from where you want the thicky to where the new outlet is placed, so that you do not need to use undersize or overlength extension cords to power the unit in service, and can eliminate an extra plug and socket and their voltage drop contributions.

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