M1450B AC TECH help needed
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  1. #1
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    Default Transformer and M1450B AC TECH vfd ? help needed

    I have been reading here for some time, now retired and have time to work on my own stuff.
    I got 3 M1450B AC TECH vfds
    In an auction lot. I also bought 2 Powermatic model 90 wood lathes that have 1 hp 3 phase motors that can run on 220/440 volt @ 3.2/1.6 amp. The vfds are 400-480 volt rated for 5 hp
    I only have single phase 220v in my shop.
    I have been reading a lot of stuff here about vfds, transformers and using them to the point of confusion...I have tried wiring the 1450b with 220v single phase in as some of the lower hp models in the series allow single phase in I just get under voltage fault, nothing about missing leg.
    So after all that I am hoping for input from you people about a plan to move forward.
    Will the vfd work if I find a 220v to 440v transformer, and what kind and where?
    Or should I just get a different vfd?
    If the transformer would work i could switch back and forth between the 2 lathes.
    But the ultimate plan is to restore both lathes and sell one of them so using the ac tech would be best for the resale if transformer is not more expensive than a different vfd.
    Thanks in advance for any input at all!
    Dale
    Last edited by DEH; 11-16-2020 at 09:56 AM. Reason: Better title

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    1. If you buy old VFDs at auctions, you most likely need to do what is called a "Capacitor Reforming Procedure" BEFORE you apply ANY line power to them the first time, or you might damage the capacitors. You may be too late in this case. Capacitor reforming is necessary when VFDs are unpowered for long periods of time, some as short as 1 year, but all if more than 2 years. In an auction / eBay etc, you have no way of knowing how long they have been sitting unpowered. In this case, AC Tech was sold to a German company called Lenze in 1999, so the name AC Tech on the product indicates it is at LEAST 7-8 years old. (they didn't change the name on products right away).

    (Edit) It appears as though Lenze never changed the labeling of the MC Series drives, so not saying "Lenze" on them may not be a reliable indicator of age. It is an old product for them though and although you can apparently still buy it, they don't show it up front in their web pages, you have to drill down to a "Previous Products" link to find it, where it indicates it is still available.

    2. Yes, you would need a transformer to get to 480V on the input, even if it is single phase. That is a 5HP VFD, so even with a 50% de-rate for single phase input you are fine, but be aware that you might not be able to program the motor Overload Protection low enough to cover your 1HP motor. I'm not familiar enough with AC Tech drives to know what they are capable of, but most mfrs will have a limit o 50% of the rated capacity, you are only at 20%.

    3. Even though it is a 5HP VFD, you COULD use a transformer size based on the de-rated motor power, i.e. size the transformer for 2HP, which would mean a 5kVA 480-240V single phase transformer. It will cost around $500 new, maybe a lot less used if you can find one, but will weight around 75lbs, so you would want to find one local that you can pick up, otherwise shipping will cost you another big amount.

    Given that you may have already toasted the VFD, and this other cost, a simpler route may be to just spend around $200 for a new VFD capable of 240V single phase input, 230V 3 phase output. There are LOTS of inexpensive options out there for those (just stay clear of the cheap no-name Chinese junk drives on the internet).

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    Thank you for your input, I really appreciate it.

    1. I realize i may have toasted this vfd, although it faulted to "under voltage " i still have 2 more. I read about "capacitor reforming" after powering it up on 220v.

    2. The manual states overload range of 25-100% not 20%, opinion?

    This is not a production application just a hobby shop.

    3. Do I really need a 5kva transformer?

    The calculators I have found put 4amps @ 220v = .88kva and 4amps @ 440v = 1.76kva what am I missing?

    Thanks again for your help,

    Dale

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    VFD input rating is not based on the output rating you are using. You are going to spend more on a heavy transformer, wiring etc. then it would cost to get something like a Teco L510 which would run around $130 for a 1 Hp, and it could be either 120 or 240V version. Let alone trying to sell something with an ancient oversized VFD and heavy transformer running at 440V for a measly 1 Hp 3 phase dual voltage motor. You also have more issues with insulation breakdown at 440V on an older motor with a VFD. Doesn't add up and probably devalue the sale.

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    2. You would have to add an external OL relay between the VFD and motor, more cost, wring etc.

    3. 1.6A is your motor FLA at 440V 3 phase, but the current at single phase increases at the square root of 3, so 1.8 x 1.732 = 2.77A.
    But you are right, I was looking in the wrong column on my transformer capacity chart (I was looking at the 240V current in the 480V column...).

    Actually a 1kVA transformer can deliver 3.1A at 480V, so that would be fine.

    Still not worth it in my opinion. Small decent quality VFDs are too cheap to pass up now.


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