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  1. Replies
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    Might be real interesting to take a standard 4...

    Might be real interesting to take a standard 4 pole 3 phase motor and bring 24 wires out.

    A standard 9 wire connection for 240/480v. 4 pole 1800rpm.

    And a 24 wire connection for 240v only,...
  2. Replies
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    1,056

    There is no way around it, torque is related to...

    There is no way around it, torque is related to flux density.

    Typical 2 speed motors are connected in series like a 480v 9 wire motor, but for the low speed they are connected in anti series which...
  3. In america the 120/240 is delivered via a...

    In america the 120/240 is delivered via a transformer with the center tap grounded.

    In australia or the uk, when you generate 3 phase you have made a corner grounded delta system with no neutral,...
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    1,832

    I have a 3 MT 1-1/32 highspeed drill bit....

    I have a 3 MT 1-1/32 highspeed drill bit. (definitely not 18% tungsten but it shows some red sparks.)

    And I have a mystery 3 mt 1-1/8 carbon steel bit.
    And chicago-latrobe 55/64" all three are...
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    2,868

    I believe i already said this elsewhere, but the...

    I believe i already said this elsewhere, but the 50 cents per kva per month, which is a demand charge only counting kva if it is more than 48% of the kw demand.. Which means they only bill you if...
  6. Replies
    23
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    1,190

    i made a surface grinder by taking an already...

    i made a surface grinder by taking an already existing 7 foot long box beam weighing 300 pounds, welding four inverted V pieces to the sides of the beam about 2 feet apart by 1 feet apart, and then...
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    181

    Looking on their website they show some photos of...

    Looking on their website they show some photos of the control box, and it does not appear to me that they have the circuitry needed to add and remove capacitors to keep the voltage balanced. -as...
  8. 3 bearings in the vise, one loaded between the...

    3 bearings in the vise, one loaded between the other two, and belt drive the shaft. No need for additiknal pillowblocks to compensate for the moment or bending force produced by 2 bearings in the...
  9. Replies
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    853

    Its the current spike that would destroy the...

    Its the current spike that would destroy the drive, voltage is clamped by diodes to the dc rail of the vfd.

    I measured peak current for 1/2 line cycle at double the locked rotor current on a...
  10. Replies
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    1,381

    try mixing up a pile of pennies and some aluminum...

    try mixing up a pile of pennies and some aluminum beer cans until it flows right at low red heat.

    press wax on your arbor spindle.. then unthread it.

    pour plaster of paris around it.. burn out...
  11. Replies
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    could be 5/8-10tpi acme seems unlikely to me...

    could be 5/8-10tpi acme

    seems unlikely to me that they would take an M16 thread and shave the OD down to be 5/8"
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    just do it. buy the right sized 5% line/load...

    just do it.

    buy the right sized 5% line/load reactor and install delta capacitors after the filter. put the vfd and the reactor inside a sound proof box and you wont hear the whine.

    2hp vfds...
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    It is more likely you had a loose connection that...

    It is more likely you had a loose connection that was "fixed" when you rewired it.
  14. a 120v in, 240v out, 1hp vfd isn't expensive. so...

    a 120v in, 240v out, 1hp vfd isn't expensive. so that's the easy part.

    rpm limits are specific to the bearings you've got, how much clearance, how much wear, etc.

    i can run my sb9 lathe with...
  15. Replies
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    2,868

    No significant kwh cost to doing so, but the no...

    No significant kwh cost to doing so, but the no load losses in the transformer will increase slightly. If the transformer is 98% efficient then for every 1kvar of capacitors you will be losing 10...
  16. usually for reversing motors capacitor start, you...

    usually for reversing motors capacitor start, you have 6 wires.

    anyhow, T5 and T8 are almost certainly your start winding. one of them goes to the capacitor, then the switch, then the winding,...
  17. Replies
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    It is ok if they have exactly the same ratio. ...

    It is ok if they have exactly the same ratio.

    Anyhow in washington state, far as i can tell, the additional kva charge by avista energy is 50 cents per kva per month. This value is really close...
  18. yeah i got that backwards. if you download...

    yeah i got that backwards.

    if you download the gauge block handbook from here
    https://www.nist.gov/system/files/documents/calibrations/mono180.pdf

    the histogram on page 35 is unlabeled.
    ...
  19. hardened steel shrinks with age due to transition...

    hardened steel shrinks with age due to transition in the crystal structure. you can actually take off the shelf drill bits and treat them in liquid nitrogen to get a statistically significant...
  20. its like they intended the machine to be be...

    its like they intended the machine to be be corner grounded delta.

    i don't know why it would matter. any sensible person doesn't run a connection from phase to ground. its run from phase to phase...
  21. Its not the belt. I use a belt made from...

    Its not the belt. I use a belt made from fiberglass reinforced packing tspe and i run it until it falls apart (the crown fatigues the strands in the middle of the belt)

    Anyhow youve got 3 degrees...
  22. Replies
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    Rewire the motor for delta and run it from a 480v...

    Rewire the motor for delta and run it from a 480v vfd reprogrammed for 377vac/60hz

    Or just run it from a 480v vfd programmed for 480v 48hz. Youll get full torque up to 48hz


    You can run a...
  23. Replies
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    Try adding a 20 or 30hp 5% line reactor after the...

    Try adding a 20 or 30hp 5% line reactor after the phase perfect, then add 100uf x3 caps after the line reactor. Delta connected.

    The phase perfect can supposidly direct online start a motor equal...
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    Bolt the gate post to a flange set in the cement....

    Bolt the gate post to a flange set in the cement. In the event the soil moves you can shim the flange
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    fatigue limit for the cast iron bull gear is on...

    fatigue limit for the cast iron bull gear is on the order of 40 foot pounds of torque, which is why those lathes shipped with a 1/3rd hp motor, which is all they can deliver, and its about how much...
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