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How to wire a motor and VFD

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by rocketmann, Feb 22, 2006.

  1. rocketmann


    Dec 24, 2005
    HELP!!!!!!!Ok,here's the problem My marathon electric model#cva56t17f5325jp, 2hp, 3ph motor and TECO fluxmaster 100 ac inverter arrived today.I have no idea on how to even begin to wire this thing up....I want to use a standard male dryer plug for power(230). Does anyone have a drawing or easy to understand wiring diagram that I can follow?? I am not an electritian so it has to be really simple (put red wire here..) I hope that someone can help with this as I've already spent enough cash on the KMG and powertrain, I would hate to have to hire someone to come out here and hook it up for me...thanks in advance..
  2. rocketmann


    Dec 24, 2005
    Well I did a search and found some good info. but i'm still not too sure of myself when it comes to this stuff (can't I just weld it all together??:eek: )
  3. Darren Ellis

    Darren Ellis

    Sep 14, 2002
    LOL, if you hook it up wrong, it'll weld itself together, along with you! :) Just kidding...well sort of... :)

    If you can't figure it out from the archives or posts that others make, give me a call and I'll see if I can help you out over the phone...I've only got to teach one class tomorrow and then run an errand to pick up some supplies, but I should be free in the afternoon...If you don't catch me, just leave a message and when I get back I'll give you a callback.


  4. pso


    Oct 29, 1998
    Hello Rocketmann

    Have a good read through the VFD manual. It should show how to hook up to the mains supply and to the motor. The manual should also tell you what sort of wire you should use for the connections to the mains supply to the motor. There is often a "get started quick" section that does not get into all the fancy programming.

    If your VFD supports them, the manual should also show how to connect up any remote ON/OFF switches and speed control potentiometers (pots). This would allow you to mount it on a wall, out of the path of the dust from your grinder. The parts for the remote speed control pot will cost $25 or less. Let me know if you want the part numbers and links to where you can get them.

    Please resist the temptation to mount the VFD right next to your grinder.
    Most of the VFD's are designed to tolerate "non-conductive dust". The stuff coming off your grinder would definitely have to be considered conductive dust. One of the other forum members just had his VFD blow up recently because of the conductive dust that had accumulated in it. It was not practical (too expensive relative to the purchase price) to repair it. It is likely that yours would not be practical to repair after such a catastrophic event either. The service department where I work scraps pallet loads of VFD's that have been returned from customers for the same reason.

    Good luck!

  5. rocketmann


    Dec 24, 2005
    where should it be mounted? I would think that it should be pretty close to the grinder so that you can make adjustments correct?
  6. pso


    Oct 29, 1998
    Hello Rocketmann

    Mount your VFD where the dust from your grinder will not be blasted into it. Off to one side would probably be a good bet. It would depend on the layout of your shop. Usually, the remote controls can be mounted something like 10 feet away. You would use the remote speed control pot to change the speed of your grinder and a switch to turn it on and off. These controls can be mounted on a small panel right next to your grinder. I would also suggest using a twist-and-pull-on, push-off switch with a big red "mushroom" button for the ON/OFF switch. These are used in all kinds of industrial applications. A quick slap on the mushroom and the machine is off. I can look up some part numbers at work tomorrow if you need them.

    The fancy programming to do things like control how fast the speed ramps up or down, the current limits, etc. would be done using the keypad on the front of the VFD. You should only have to do this programming once when you first set it up. Many VFD's have some sort of communication capability (RS-232, RS-485, MODBUS, etc) so the programming can be done via a PC without having to touch the keypad on the front at all.

  7. deker


    Nov 14, 2005

    Since you seem to know a thing or two about this stuff, I've got a question re: enclosures. Would it be OK to mount the VFD inside another enclosure (I'm thinking something like a small electrical box, possibly one designed for outdoor use that will be sealed to some degree) and have the switch/pot mounted outside that enclsure? I'd like to keep the VFD setup mounted to the same overall platform as my grinder so that the whole kit & kaboodle can be picked up and taken someplace.


  8. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    Be careful in mounting your VFD in an airtight box.It needs air flow to cool the heat sinks.Blowing it off/out with an air hose every so often to keep the dust from building up is a good idea,too.
  9. rocketmann


    Dec 24, 2005
    Is it necessary to have a seperate on off switch? If it is how do I wire it in? I am using 220v. I guess the switch would go between the source and the VFD. but since I have 2 hot legs comming in how do I wire it? ( I'm not good at this)also the remote would a long cable for the pot and a long flat wire connector for the controls(20 pin I think?) thanks for the help..:p
  10. pso


    Oct 29, 1998

    Stacy is right. The VFD's are designed to have unimpeded airflow to keep them cool. Putting them in a sealed box requires a heat exchanger mechanism. They do this here for certain special applications that can bear the extra cost of the heat exchanger.

    The cause of the other forum member's VFD blowwing up was likely to be the metal dust being moved around to the "wrong place" when he was vacuuming the dust, with the input power turned on. The lesson here is that if you must blow/suck the dust out of your VFD, make sure that the power is off before you start.


    Look on page 11 and 13 of the "Maintenance Manual" to see how to connect the input mains power and your motor. It can be downloaded from www.twmi.com/products/controls/drives/FM100. I suspect that you have a 220 V, single-phase supply so you will be using the L1 and L2 terminals. The motor wires would connect to the T1, T2 and T3 terminals. The motor wires are likely to be marked T1, T2, T3 or U,V,W as shown on page 11. Don't worry about the "Thermal Relay" and "Thermal Overload Relay" shown on page 11. They are really only used on much larger (more expensive) motors and VFD combinations. If your motor ends up turning the wrong way, swap two of the motor wires. According to the National Electrical Code, you should use at least least 14 AWG wire for the power and motor connections if you have a 2 hp VFD. Use at least 12 AWG wire if you have a 3 hp VFD.

    Go to pages 11 and 28 to see how to connect the remote speed setting potentiometer. Use the connection scheme shown at the far left and program Fn_11 to the value described. If you are willing to spend up to $25 get a 10-turn potentiometer (3590S-2-103-ND) and a matching turn-counting knob (H-550-6A-1-ND). It will give you very fine control of your speed. A less expensive option is a single turn potentiometer (RV4N103C-ND) and a normal knob (8556K-ND) at about $11 - $12. I have given the Digikey (www.digikey.com) catalogue numbers for each item. All of these parts are of good quality from reputable manufacturers that I would have no trouble using in the equipment that I design.

    Go to page 24 to see the various options for the ON/OFF switch by your grinder. If you need to be able to reverse the direction of the grinder, use the middle connection scheme. If you only need the forward direction, then use the lower connection scheme but omit the switch for "Reverse". Of course, you will have to program the values for Fn_10 and Fn_03 as shown in the manual. I would recommend the Z1502-ND from Digikey at $28.58. It is sealed against dust and water and has a big, red "mushroom" that a quick slap of the hand will stop the power to the motor in an emergency. Keep in mind that the VFD is still live and that your dryer plug is still your "power switch". You could install a 220 V, double pole breaker between the power cord and the VFD to act as a switch and give you some protection in case something bad happens inside your VFD. If you have the 2 hp VFD, use a 15 A breaker. If you have the 3 hp VFD, use a 30 A breaker. These sizes should make you "legal" with the NEC.

    The wires used for connecting the switch and remote potentiometer can be anything from 20 AWG and up since the current is very small. A piece of network cable would work. A plastic dual-gang electrical box with a blank plate from Home Depot would be a good choice to mount the switch and potentiometer on.

    If possible, have a qualified electrician confirm the wire size and circuit breaker sizes and check your wiring.

    Sorry for the long post. Hope this helps.

  11. rocketmann


    Dec 24, 2005
    thanks, I'll look some of this up.:D
  12. dan_barber


    May 13, 2009
  13. silver_pilate


    Oct 30, 2002
    Dan, thanks for the link. It will add some information to this post for others who are searching. You did realize that this is a 3.5 year old post, didn't you? :)

  14. trickymick


    Aug 4, 2009
    even though this thread is 3.5 years old i though id add that if this is a 3p motor and he's only using 220v single phase it wount work. if you try to wire it up that way the motor wount run and it will burn up.
  15. silver_pilate


    Oct 30, 2002
    You can run a 3 phase motor off of 1 phase 220V, you just have to make sure and run a VFD that accepts both 1 and 3 phase input and outputs 3 phase. That's how my motor is set up for my KMG.

  16. Mark Behnke

    Mark Behnke

    Apr 16, 2008
    remote mount controller in 10" by 10"x6" deep electrical JB
    Variable spd. on-off and 3 preset spd. switches mounted on bench in 2 gang Bell box.

    Attached Files:

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