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Hf Mini Lathe Pwm Woes!

Discussion in 'HARBOR FREIGHT, CENTRAL MACHINERY & BUSY BEE' started by rake, Dec 18, 2016.

  1. rake

    rake United States Swarf Registered Member

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    City:
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    I've bought more of these than I care to admit.
    The best one came from China (ebay) it was a 500w
    unit and lasted 18 months.

    I'm seriously considering trying a multi tap transformer and
    just having set speeds by voltage.

    Any ideas or other suggestions would be greatly appreciated!

    Thanks in advance.
     
  2. Tony Wells

    Tony Wells United States Vice President Staff Member Administrator

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    PWN is not at all the same as varying voltage. You can't substitute a voltage decrease for decreased "on" time during the power cycle. If anything , you might gain a little (and give up a little) by lowering the input voltage to the PWM device. I don't mean drop the input to control the motor speed, but just to make sure the components of the device don't see the max line voltage. Limit it to 100-105 volts or so. Everything should run "less stressed", cooler and live longer. BUT, if there is a problem on the load side, as in an attempt to draw more current than your PWM device is designed for, it will still fail, and perhaps sooner. You should verify that there isn't a load problem first.
     
  3. rake

    rake United States Swarf Registered Member

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    Thanks for your reply Tony.
    I upgraded my machine to the "long bed" kit from LMS.com
    and also purchased at the same time a new motor and 350w speed controller.
    And still had similar issues. (still have the old motor too)
    You may be on to something with input power being the issue as we all have had
    issues with computers and hvac equipment in our location. (rural area and old grid/equipment)

    May try a couple of 12v transformers coupled front to back. I've seen that done to drop 120vac down to 100vac
    before.

    Since that 500w Chinese unit lasted the longest I'll probably get another one of those.

    Also considered trying a 230v controller since the shop is wired for both.

    thanks again.
     

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