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    Variacs USED TO be cheap, then all of the wannabe...

    Variacs USED TO be cheap, then all of the wannabe guitar heroes found out about using them on the amps to get certain effects and all of a sudden, the prices on used ones skyrocketed, at least from a...
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    That Leviton toggle switch IS rated for HP, but...

    That Leviton toggle switch IS rated for HP, but it's 2HP at 240V. You have a 5HP motor. No good...
    https://www.leviton.com/en/products/3032-2i

    That's why I said you CANNOT go by amps alone....
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    Yep, that's one of the consequences of a broken...

    Yep, that's one of the consequences of a broken shading coil. Random directions.
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    GPD503 was capable of accepting single phase...

    GPD503 was capable of accepting single phase input, but needed at least a 50% de-rate. A 30HP drive for a 5HP motor is overkill, but would work, so long as you pay attention to the settings for motor...
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    You can't go by amps alone, a switch must be...

    You can't go by amps alone, a switch must be rated for the HP, in your case 5HP. Yes, it will need to be 2 pole. What you can likely find with the right ratings will be called a "Manual Motor...
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    Shaded Pole motors have very low torque, so it...

    Shaded Pole motors have very low torque, so it doesn't take much in the way of bad lube, grime, bearing friction etc. to stall them. On the plus side, they tend to last forever if you keep them clean...
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    A Repulsion Start - Induction Run motor has some...

    A Repulsion Start - Induction Run motor has some similar looking parts, but they were not variable speed.

    Actually what you have there is called a "Schrage motor", used a lot in textile machinery...
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    In theory, maybe, but even if, it wouldn’t make...

    In theory, maybe, but even if, it wouldn’t make economic sense on something that small. It would cost more than buying a new motor.
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    Doing the math, that's more likely a 208 to 460V...

    Doing the math, that's more likely a 208 to 460V transformer, which would make more sense than a 240-530V...

    And the voltage you measure with no load on it is not going to be the same as when it...
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    Typical NEMA design specs are +-10%, so a 440V...

    Typical NEMA design specs are +-10%, so a 440V rated motor would be OK with up to 484V, meaning you are on the ragged edge of acceptability there. But is your incoming voltage actually 240V AT THE...
  11. A motor like that is so rare and oddball that...

    A motor like that is so rare and oddball that nobody would bother making a VFD for it.

    However you COULD just program a 230V VFD to only put out 115V at the proper Hz, in this case 60Hz. Any VFD I...
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    Reader's Digest version of what the issue is. ...

    Reader's Digest version of what the issue is.

    In years past, the magnet wire used to make motors was made to handle at least 2x the expected line voltage. With the advent of VFDs, the way they...
  13. The reason you generally can't "soft start" that...

    The reason you generally can't "soft start" that type of motor is that the capacitors needed to make it start are not rated / intended to be in the circuit for any length of time, they are take out...
  14. Don’t bother with all of that nonsense. Just...

    Don’t bother with all of that nonsense. Just permanently connect the motor in the highest speed and use the VFD to lower it.
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    The risk you run will be based on the VFD...

    The risk you run will be based on the VFD internal protection capabilities. A 10HP drive fed with single phase for a 7.5HP 3 phase motor is not large enough to provide the proper DC bus capacitance...
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    It's customary to start a new thread and...

    It's customary to start a new thread and reference an old one rather than resurrect a "zombie" thread. But it's done now.

    The issue you will have is that your motor speed will be limited to 58% of...
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    What you measure with no load on it is not as...

    What you measure with no load on it is not as important as what it is going to be under load.
  18. Technically, any VFD is capable of accepting...

    Technically, any VFD is capable of accepting single phase input and giving you 3 phase output, it's just that some mfrs don't let you do that. That's because on a lot of 480V rated drives, they don't...
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    480V utilization equipment is made for 460V to...

    480V utilization equipment is made for 460V to allow for voltage drop from the service point to the motor, then is +-10%, so 460-46 = 414V as the absolute minimum that a 460V motor can receive and...
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    Adding a load reactor does absolutely nothing...

    Adding a load reactor does absolutely nothing with regard to the line side. It's on the LOAD side. You want a load reactor if the motor is old and was not made for use with a VFD. 1950s motor,...
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    A contactor is NEVER an appropriate Lock-Out /...

    A contactor is NEVER an appropriate Lock-Out / Tag-Out point for servicing a machine, you MUST use a lockable disconnect switch. OSHA would have you and the business owner castrated for doing this...
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    Power conditioner on a compressor? Odd. Might it...

    Power conditioner on a compressor? Odd. Might it be a buck-boost setup to compensate for a voltage drop? That makes more sense on a compressor. It would help if you could post photos of the...
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    Quick and dirty rule of thumb on what it buys you...

    Quick and dirty rule of thumb on what it buys you to add an encoder:

    V/Hz control mode, 1-2% speed tegukation.

    Sensorless Vector Control: 0.1% speed regulation (10x more than V/Hz)

    Flux...
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    Herein lies the flaw in your thinking. That...

    Herein lies the flaw in your thinking. That highlighted statement has ONLY to do with IEC designed motors (meaning designed for use in Europe and Asia), it is NOT true of NEMA (North America) design...
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    Unless you are lifting water from an extremely...

    Unless you are lifting water from an extremely deep well, this is actually a perfect application for a VFD. 575V is an issue, most of the inexpensive brands don’t do that. I would look at finding an...
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