Hitachi VFD Question
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  1. #1
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    Default Hitachi VFD Question

    I have a Hitachi WJ-200 series inverter that I run three different tools off of in my shop. I have it set up on a 10/3 4 wire rubber cord. When I run a particular machine, I just switch the cord. I power a Clausing 13 inch lathe, a Boyer Schultz surface grinder, and a Kalamazoo hack saw off it. I believe the unit is rated for 3hp max load. 240 V single phase input, 3 phase output. I recently purchased a Cincinnati Bickford Super service drill press and when I try to power it, I keep getting an error code on the VFD. I wired is just like I did all of the other machines, and had no issues with the ones I'm running except for switching two wires to reverse the direction of the surface grinder. The spindle and pump that works the table feed was turning the wrong direction. After I switched the wires, it ran fine. I tried switching 2 wires on the drill press, but still get the same code. The code is E013. The press is 240 Volts, 3 phase. It has a magnetic switch that reverses the motor for tapping operations if you desire to use it for that. IN the control box, there are three feed wires and one ground. The ground wire attaches right to a lug in the switch box. Anyone have an idea what my problem is? The only thing that I can think of is that maybe the coils that actuate the reversing switch run on single phase and the switch is not wired correctly, hence the error code. I'm no electrician, but I do know my way around machine wiring a little bit. This has me stumped. The VFD runs all the other tools fine. I'm going to look at the wiring schematic on it at Keith Ruckers vintage machinery website to see if anything look incorrect. I am attaching a link to the manual in pdf for these drill presses. On the last page there is a simple wiring diagram. Any help or suggestions would be appreciated.

    http://vintagemachinery.org/pubs/2543/16737.pdf

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    E13 in my manual for WJ200 says unattended start protection is tripping.

    Meaning I think— you are powering up the VFD while run command (via control
    wires I assume) is already asserted?

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    And you should not have any switching between the VFD
    and the motor, so what you describe for reversing on
    Tapping operations is a bad idea when 3phase comes
    from the VFD. You would either need a much bigger VFD
    Sized for the locked rotor amps of the motor, or change
    The wiring to reverse via the VFD... but you
    Would also need to make sure the acceleration and
    Deceleration meet the needs for tapping...

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    Check your control wiring. Perhaps you have a NO switch when you need an NC or vice versa. IIRC you might be able to change this by moving a wire. And also, what is the HP of the drill press motor? As already noted, you must watch out for the LRA when running this way.

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    Thanks for the replies. The motor on the drill is 3hp. My lathe has a 3hp,,,two speed motor and it runs that fine. I never switch speeds while it is running. I bring the machine to a full stop, and then change speeds and turn it back on. I don't used the VFD to control speeds at all, use the lathe gearbox for that. I will do the same with the drill once I get it figured out. I have videos of the drill running before I bought it, so it has to be something minor. I will double check the wiring.The schematic for the run relay is not clear enough to read as far as connections go. Might try to find a better picture of it. Will it harm my VFD if I keep causing the code? I power it on, and then if it does not come on, I immediately turn it off. When I got the error code, I turned the VFD off,,,turned it back on, and tried running my lathe, and it worked fine. I just don't want to cause any damage to the vfd.

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    Quote Originally Posted by PeterH48 View Post
    Thanks for the replies. The motor on the drill is 3hp. My lathe has a 3hp,,,two speed motor and it runs that fine. I never switch speeds while it is running. I bring the machine to a full stop, and then change speeds and turn it back on. I don't used the VFD to control speeds at all, use the lathe gearbox for that. I will do the same with the drill once I get it figured out. I have videos of the drill running before I bought it, so it has to be something minor. I will double check the wiring.The schematic for the run relay is not clear enough to read as far as connections go. Might try to find a better picture of it. Will it harm my VFD if I keep causing the code? I power it on, and then if it does not come on, I immediately turn it off. When I got the error code, I turned the VFD off,,,turned it back on, and tried running my lathe, and it worked fine. I just don't want to cause any damage to the vfd.

    It isn't clear to me at least what order of operations you are using to run this machine.

    Is it:

    1) VFD starts as off
    2) attach drill 3ph plug to VFD while it is off
    3) power on VFD, but not in "run" mode
    4) start VFD via "run" or "forward" command
    5) drill motor not running at this point, then you press mag switch button on drill
    6) expect drill motor to start?

    The code itself seems to suggest you don't have it this way, but instead
    you have the "run" command hard-wired so the drive is always running when
    it is getting power?

    And yet, the drive's inputs are configured for Unintended Start Protection, so
    it will lock out and require a reset when you plug it in.

    I would suggest that having the VFD in run mode and then using the magswitch on
    the drill machine is not good for the drive... as we said earlier in this thread
    the VFD is not rated to be able to start a motor of that size while the drive is
    itself already producing a 60Hz 3ph power output. Yes, it may just trip out and
    not do itself any harm, but isn't getting you anywhere.

    So, perhaps can you clarify my above questions of exactly the order you're doing things.

    BTW I'm also not clear how exactly you're using the drive on your lathe. when you
    stop and start the lathe, what do you mean? Are you causing the VFD to "stop" i.e.
    it stays powered on but you assert the stop signal or key on the front? Or, are you
    just pulling power from it (via a switch on the single phase input side)?

    And similarly to start the lathe are you just powering
    on the VFD and it starts immediately in FORWARD?

    -Phil

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    Phil, thanks for trying to help me figure this out. Let me explain how I run the lathe with the VFD. I turn the power to the VFD on. The lathe is in the off position. I have the small remote for the vfd that controls the functions. I press the start or run button. I wait until the little led ramps up to 60 cycles. Once that happens, I just power on the lathe. When I first got the vfd, I heard that you could program the vfd to change speeds on the lathe while it was running. But a friend of mine who has the same lathe as me, said you cannot use the vfd for that. He uses the same method I do for running his lathe. The motor that powers the lather is a 2 speed motor, but the speed changes are made on the lathe itself by levers on the lathe controls. I'm no electrician Phil, but I thought that was what the magnetic switches do when used on large electric motors, aid in starting them due to the large load.

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    Seems to me that you are going about this wrong. One of the major benefits of the VFD is the ability to control the speed of the motor via the VFD, giving variable speed control to a motor that otherwise does not have it. And the reason the cycle count up to 60 when it's powered on is "soft start".

    The way you are running your shop is guaranteed to cause issues like this, and eventually probably damaged the VFD.

    The ideal is:

    Individual VFDs to match the machine
    VFD output directly wired to the motor,
    bypassing the machine switchgear,
    with switches (or a VFD remote panel) connected to the VFD low voltage controls.

    Alternately, a single rotary phase convertor (RPC) to power all your machines, no plug changes rquired. This is the ideal situation in your case IMO.

    I know that doesn't answer your question, and you probably know all this.

    Using that single VFD as you are is out of the bounds of expected usage, so the standard diagnosis routine may not be applicable. What I usually do is reset the VFD to the default, then read through all the parameters until I understand each one and understand how/if it applies to my problem.

    Or....call Hitachi product support. Those guys are usually excellent.

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    My guess is that your other machines have manually operated electrical switches, or drum switches, that connect the load motor directly to the VFD output.

    The drill has a reversing contactor that is electrically operated by a set of 240V operating coils.
    The reversing contactor presents a 1Φ control load to the drive output, and it sees that as the 3Φ motor load is not connected and trips out.

    Bypassing the drill reversing contactor with a manual drum switch may get you around that problem.
    But your drive manual clearly states in the very beginning that you are not supposed to have switches between the drive and the motor, even though you have been getting away with that so far.

    It's likely that the coils in the reversing contactor won't like being powered by the pulse width output from the VFD, and could overheat and burn up.

    There is a way in the drive manual to disable the E13 unattended start protection, but that doesn't seem necessary with the other machines, likely due to the manually operated switches.

    SAF Ω

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    It's not exactly verboten to have switches, contactors, or plugs/sockets between a VFD and the motor, but it's best not to open them under load (especially with older drives), and definitely don't close them under load. The reason for this is that the drive can't supply the necessary starting current to start the motor at full speed (60Hz). It supplies just enough current to start the motor at ~5Hz and slowly ramps it up.

    You can't feed the contactor coil from the VFD output. If you absolutely needed one, it would need to come from a separate control circuit or the VFD input

    But in addition to the options given above (a VFD per machine, or a single RPC), there's one more:

    Bypass all the controls in each machine so the incoming three phase is directly connected to the motor, and add a second plug to the machine for low-voltage control wiring - a run-forward switch, and a run-reverse switch if necessary.

    You should also have an emergency stop of some kind - a contactor on the input to the drive is probably the easiest option here. Ideally you would use the safe torque off inputs to the drive which can use DC braking to provide a very fast stop, but that requires configuration and it really needs to be correct.

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    Thanks to all who tried to help me with this problem. I have decided to add a 10 HP Rotary Phase Converter to my shop like Rex TX suggested. I probably should have done that years ago. Messing around with the VFD is not worth taking a chance on shorting it out.


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