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  1. #61
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    Quote Originally Posted by Lappa View Post
    I'm interested in a 3 phase motor which is some distance away. I've asked the guy to take a picture of the motor plaque but he says it's unreadable. He took the cover off the connection box and sent me this photo.
    Can you tell from this whether the motor can be easily converted to delta?.
    TIA
    Attachment 413867
    I'm not certain but it looks like a fixed Y connection and would need to have a bot of surgery on it to convert it to ∆.

    Easily Convertible motors have a connection box that looks like this.
    2 rows of 3 connectors
    IMG_3531.jpg

    Under the cover of the connector box they usually have a diagram showing Y and ∆ connection setups like this.
    The motor above is currently connected as Y, to make it a ∆ 240V , the connection between W2 and U2, and between U2 and V2 are moved and
    new connections are established between W2 - U1, U2 - V1, and V2 - W1 as shown on the LHS of the photo
    IMG_3530.jpg

    BTW, unless you have some experience on electric motors I would be wary about buying a motor without a name plate on it and running it on a VFD.
    You have no idea what its current rating is so you cannot supply the VFD with the correct motor ratings to maintain safe motor operation.

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  3. #62
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    It's hard to be sure from that picture. Basically, there's 3 windings in a 3 phase motor and you need to get to both ends of all of the windings. So, the simplest, and most desirable arrangement for you, is that there are 6 leads coming from inside the motor into the terminal box. However, when you get access to all 6 leads, you will connect 3 of them together to make the STAR point but, in some motors, the manufacturer has already made the star point inside the motor by connecting the ends of the 3 coils and so there are four leads coming from inside the motor into the terminal box.
    The 3 phase motor on my DC had this arrangement when bought...

    image.jpeg
    ... and, ignoring the (green/yellow) earth, you can see that there are only 3 leads coming from inside the motor and so I had to get the rewinder to go in and bring out the other 3 ends.
    Can you ask the potential seller to remove any remnants of the original connecting lead coming from outside the motor (if any), unscrew the terminal block and pull it forward far enough to count the number of leads coming from inside the motor?

    EDIT, I was (too slowly?) typing my reply as Bob was typing his. As you can see on Bob's picture of the terminal box lid, THAT motor has the most desirable 6 leads U1, U2, V1, V2, W1, and W2 coming from inside the motor in to the terminal box. The movement of the changeable links simply is an elegant way to connect as STAR, which is what you need or DELTA
    a rock is an obsolete tool ......... until you don’t have a hammer!

  4. #63
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    Thanks for the replies Bobl and Fletty. The motor in question is connected to a jointer which is attached to a homemade base. From the pictures and the response from the guy, when I asked him for photos inside the cover, its right underneath and a pig to get to
    I don't think the seller is interested in more dismantling but I may approach him again when the auction runs out if he hadn't sold it.
    As Bobl said, without info on current, kW etc. it's going to be difficult to hook it up to my VFD. If I can get it cheap enough, I may throw a single phase on it as it's only a 6" unit and not worth spending big $$$ on.
    Cheers

    additional info. When talking to the guy yesterday re the wiring he said that it had a capacitor connected. Is this normal on a three phase motor?
    Last edited by Lappa; 10th June 2017 at 01:46 PM. Reason: Additional info.

  5. #64
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    Quote Originally Posted by Lappa View Post
    When talking to the guy yesterday re the wiring he said that it had a capacitor connected. Is this normal on a three phase motor?
    No its not normal. It sounds like he's been running it on single phase. If so it's not really that good for it in the long run.

  6. #65
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    It's got a 3 phase plug?

  7. #66
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    Quote Originally Posted by Lappa View Post
    It's got a 3 phase plug?
    Sorry I'm stumped at this point.

  8. #67
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    Im not liking the sound of this? All I can think of is that it is a single phase motor being run on 3 phase with the capacitor acting as a static inverter? Single phase ( which is really 2 phase) motors usually have a capacitor start winding because a single phase motor can't actually start because its 2 power phases are 180 deg out of synch and FOR THE SHORT DURATION OF STARTING, the capacitor acts as a 3rd phase to get the rotation started? BUT, why would you run a single phase motor on 3 phase?
    a rock is an obsolete tool ......... until you don’t have a hammer!

  9. #68
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    This might be a stupid question but here goes. When running a 3 phase motor through the vfd would it use the same number of amps as a single phase 240v motor of the same HP?

  10. #69
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    Yes it works out about the same - the VFD itself uses some 10's of mA which is over and above that.

  11. #70
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    Cheers Bob, good to know.

  12. #71
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    I'm looking at a 415v 3hp extractor that's for sale. It's miles away so I haven't looked at it but got a picture of the motor plate.

    IMG_0304.JPG

    Does this definately mean it an it can be converted to delta for my VFD or just a maybe?

    cheers

  13. #72
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    Yes. The delta connections are shown on the top RHS of the plate.

    P.S. Or bottom left if you have the photo the right way up.

  14. #73
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    Not necessarily. It only has values for Star on the plate. It may be a generic plate that is used for all motors. You need to look inside the terminal box to be sure.
    Where is it Peter? Can someone closer have a look?
    Those were the droids I was looking for.
    https://autoblastgates.com.au

  15. #74
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    It's up past Kumond and it's on ebay ending Friday so not much chance of a look see It was just a thought and not an essential and getting it home was another matter so I'll wait for one closer.

  16. #75
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    I have been dealing with Powtran in China to purchase a decent quality 3P-3P VFD.
    I started out trying to go through their Alibaba portal but that was hopeless so I approached them direct and their response has been EXCELLENT.

    Powtran's latest entry level Vector Drive VFDs (PI9130A series) are full vector drive with the braking circuitry built in, dual speed potentiometer, dual displays and a host of other features - most of which we will never use.

    The standard large red LED display shows any value that a machine operator would need to see, while the smaller 4 line OLED (multi-lingual) display screen shows other parameters and is useful for programming. These are much more ruggedised units than the comparable Huanyang VFD models and given the quality, the prices are very reasonable.

    You have to ask for a quote and while Was at it I asked for some 220-380V model prices and this is what they provided.
    Their 1.5HP model (1R5G1) is US$115
    The 3HP (2R2G1) is US$129
    5HP (004G1) is US$160
    Delivery via DHL is US$40

    I ordered a 1.5HP 3P-3P VFD (1R5G3)and it was the same price as the 1R5G1.
    So for a total of AUS$200 I get a full vector drive VFD with a host of useful features.

    The contact email is [email protected]
    The contact name is Nicole Chan.

    Back in post #11 of this thread I did a side-by-side comparison of an older model Powtran (PI9100 series) with the HY and you can see some of the differences.

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