Victor Lathe tie in point!?
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  1. #1
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    Default Victor Lathe tie in point!?

    I'm currently running my shop off a 10kw military generator and the constant starts of my 16" victor lathe is hard on the gen-set. To solve this problem i got a vfd so i can soft start the motor. The vfd can handle fwd/rev so i don't need those contactors but i do need the high low stuff.
    I was really worried about figuring out how it was wired. when i opened the electrical panel i found a circuit diagram in a plastic bag taped to the inside of the door. Wholy shit someone thought of the next guy!!
    20190919_211009.jpg20190919_210949.jpg
    The bottom 3 contactors are high/low, the top two are fwd/rev. one of the center ones is for the coolant pump but the two things with the red dials I'm confused about. can anyone help?

    Once i get set up for the day i plan to live stream on youtube as i work on this.

    YouTube

  2. #2
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    If it is a constant Hp motor, than just run it on the 8P setting and run it to 120Hz. If the motor is not constant Hp then run it on the winding that gives you the highest Hp and use the VFD to adjust the speed range. It is also possible on some VFD's to have two parameter sets for different motors/windings, and one can select via a VFD programed input which motor set to use. I have done this with 2 speed motors where the switch passes through a stop function and then switches the motor connections and signals the VFD to load a different parameter set. In most cases more trouble than it is worth, and I have had more problems with 2 speed motors running well off of VFDs, even when wired for a single winding.

    On these type of lathes/control systems, I pretty much replace all the control board components and all the switch/light gear, just find it easier at the end of the day. It is possible to strip the high voltage wiring from the the forward and reverse contactors and use one set of contacts to switch the forward and reverse VFD input signaling wires. I replace the contactors with new ones or use relays, as the burnt contacts do poorly in conducting low voltage signals. In theory one could use the 2 speed contactor to switch the motor connections and add a switch to signal the programmed VFD input to switch the motor parameter set. Not ideal, but possible. As mentioned, I have done this on a rotary switch which changed the motor winding connection and also low voltage signaling input to the VFD.

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    the things with the red dials are the overloads. That functionality is built into a VFD. You'll probably want to keep the overload for the coolant pump.

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    So after some reverse engineering and lots of cussing i've hit a wall. the fwd/rev control is a lever next to the head stock and on carriage, up is fwd, down is rev and center is off. the headstock also has a fwd jog button. there are 4 wires from the fwd/rev switch that are connected in the following manner
    Fwd. 3(com),4 - closed All others open
    Rev. 3(com),5 - closed All others open
    Neutral. 3(com),2 - closed All others open
    Jog 3(com),4 - closed All others open
    All of that would be fine if it wern't for the brake pedal that also shuts the motor off. the brake pedal contacts open when the brake is pressed which has been the problem as the vfd i got has no option (that i can find at least) to invert the inputs.

    I got the huanyang gt series VFD and one of the inputs is called Coast to stop. i plan to use this with the brake pedal as any controlled deceleration will over power the brake.
    Something that has to happen is when the the machine is running and you press the brake the motor has to stay stopped until the user turns the FWD/rev lever off and back on. to acheive this i have to use the 3 wire,mode 2 fwd/rev control. while using this mode i found the lever didn't work but the jog button did. I had a theory that fwd or rev was closing before neutral was opening. i set up 2 multi meters and it was too close to tell. guess i could test it with the scope LOL.

    Been pulling my hair out for the last few days on this one. any help would be appreciated.
    If all else fails i can probably fix this with some relay logic but i'd rather not.

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    I have a victor 1640 as well and from the photo you posted looks like a twin to yours. I run mine off an RPC, while all you VFD fanboys are looking for some rotten produce to hurl my way, let me explain. When I installed it 12 years ago the budget was tight and RPC came way for little cost, plus I had no 3 phase available. I happen to like the brake / quick stop, for several reasons.
    1) It is lie having an E-Stop with in a reach in a fraction of a second, thank god I have never had to use it for this.
    2) When I get to working it facilitates fast stop to change tools check dimensions etc.
    That is me, I do see your problem I think. I am assuming your genny provides 3 P @ ~220VAC.
    So why not disconnect the switch that believe resides near the "brake mechanism" and hook it to one of the VFD inputs and use the brake feature on the VFD. Let the VFD's braking resistor handle the stop.
    Know mind you I use this lathe at my home shop, so I am not really working at a "production" pace, so I can get away with just using the change levers to achieve the chuck/direction & speed I want.
    It may not be practical in your situation, but why not pick up a cheap 10 HP RPC, let the genny run the RPC and use the controls on the lathe. The draw on the genny from the RPC would not be subject to the stop start current fluctuations. Yes RPCs are more noise in the shop and since VFD prices have plummeted not the most efficient way to power the lathe (RPCs). I do have a VFD that I will be installing on my Victor and plan to do what I described above.
    Cheers Doug
    I am really not a fan of "coasting" to a stop, I believe when coasting down it is point where accidents happen. God forbid something happens where you need to stop that spindle right quick, I want to be able to tap that foot bar have a dead stop.
    I hope I may have given you some ideas to work with. the other is to disconnect the fwd / rev switch on the lathe and let your VFD do it for you via Le Butons, no lever position to worry over, as I said. VFDs are becoming more and chockfull of features while the price drops. Good luck and I hope I did not completely miss the mark here.

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    Default Victor Lathe tie in point!?

    Itís early,no coffee yet. But Iím not following what you did.
    Did you just put the VFD to the input power wires of the original controls and are still using the contactors ?
    You mention relay logic, you need some.
    The start and stop buttons are momentary , ie they change state again as soon as your finger is off the button, or foot off the brake.
    Every VFD I recall has a stop circuit that opens to stop, that way a broken wire or failed switch stops the machine,
    The VFD start circuit(external wires) often is tied in with fwd/reverse .ie three wires going to VFD start in either fed or reverse

    You can use the forward and reverse contactor as relays and run the VFD start stop logic thru what was the three phase power contacts. Just make sure the contacts are really clean as they will have small voltages and currents running thru. This is a bit cheesy way in my opinion.




    Im on my phone I look harder later at you print , post up a VFD print if you have it
    Maybe I missed read your issue


    Edit: what I should have started with was be careful! Itís pretty easy to make a configuration that behaves dangerously. Like the lathe stops when you hit the brake , but starts again immediately when you take your foot off.





    Sent from my iPhone using Tapatalk Pro

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    I have by passed all the fwd/rev contactors in the rear panel.
    the control is a lever that stays up or down.
    I want to use the brake pedal with the vfd but the contacts are closed at rest and open when the brake is activated. This is a problem because i can't figure out how to switch the input in the software.
    I'm gonna go work on it today, I'll make a video or something.

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    Is the switch for the brake by the motor? Should be fairly easy to get to.
    See if there is a normally closed contact on the switch, or swap out the switch with something else


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    Overall a very poor design strategy to hard wire the VFD inputs to the spindle control as you have outlined, there are no safety interlocks or resets through the stop position. The foot brake switch can be wired for either NC OR NO, so depending on the design it is a simple matter as to switching a wire to have it do what you want. Some VFDs you can change the input activation state from NO or NC. When you step on the manual brake you want two separate actions to occur, one is to interrupt power to a latching relay that in its energized state allows the forward/reverse commands, the second is to issue a free run command to the VFD so only the mechanical brake is stopping the machine and not the VFD. Under normal conditions or use of an E-Stop the VFD will brake the machine. This type of setup typically uses a main power relay that is energized when the spindle switch is in the center position or through a separate push button switch. I typically use 2 wire control with relays for forward, reverse, power...etc. There are some different designs that have been posted in different forums.

    I would have recommended an RPC if you cannot safely implement a VFD properly.

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    i guessed i failed to mention the purpose of the VFD. My shop is currently running on a MEP-803A 10kw (12.5Kva) diesel generator which produces 120/208 3 phase. this is more than enough power to run the lathe but it has a hard time starting. i don't worry about starting my other machines as they are either smaller or have a clutch. bottom line the prime objective with adding the vfd is being able to soft start the motor. all the other features are just a bonus (that there is no way i'm not going to play with)

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    An easier alternative may be to switch the motor to something that is the next size down. The Victor 1640 seems to come with either a 5 Hp or 7.5 Hp motor, I doubt the latter would be able to start with a 10kW gen-set. There are some losses through the VFD, so I am not sure at the end of the day you will be ahead of the game. There are soft start units, but expensive and most have limited number of soft starts per hour.

    A 5 Hp motor would need something like a 10-12.5 kVA Generator.
    Guide to Choosing Generator to Motor Size - National Pump & Energy

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    Quote Originally Posted by silencerman View Post
    i guessed i failed to mention the purpose of the VFD. My shop is currently running on a MEP-803A 10kw (12.5Kva) diesel generator which produces 120/208 3 phase. this is more than enough power to run the lathe but it has a hard time starting. i don't worry about starting my other machines as they are either smaller or have a clutch. bottom line the prime objective with adding the vfd is being able to soft start the motor. all the other features are just a bonus (that there is no way i'm not going to play with)
    Your lathe do as you wish- as I alluded to, and was spelled out in better detail above- do you really want to rely on a bunch of ones and zeros inside the VFD to keep your hands and possibly your whole body safe? Thatís what you are doing if you donít have a external contactor that drops out when you hit the brake.





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