# vfd grrrr snag



## nightowl499 (Sep 26, 2014)

just starting to look at putting the vfd on my Harrison lathe now i see  the motor has six wires...?  6 pole??

not sure how to wire the vfd three to the six  on the motor.  any thoughts ??


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## caspaincmonster (Sep 26, 2014)

Is it 2 speed? A picture of the motor plate would be helpful.


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## nightowl499 (Sep 26, 2014)

I will take a picture of it tomorrow and get info on it the specs on the plate on motor doesnt say anything about 2 speed but will look closer


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## CluelessNewB (Sep 26, 2014)

It might be no big deal.  Most common motors seem to be dual voltage 9 lead.   Single voltage may just have 6 leads (or 3).  The link below shows several 6 lead motor hook ups: 

http://www.firstelectricmotor.com/motor_connections.htm

It might be this: 

Single Voltage Wye or Delta 6-Leads


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## nightowl499 (Sep 26, 2014)

ok looks like the extra wires are figured out turns out they do pair up to just three on a terminal strip, so here is a pick of what im fighting with anything look familiar


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## nightowl499 (Sep 26, 2014)

ok looks like the black thing in upper right is on off switch door the interlock. to right of that is the apron fw rv off switch, the blue row of box's are
breakers middle one marked spin the bottom row appears to be the contactors  and next to the blue breakers is a transformer for the contactors

hmm its kinda sorta making sense


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## JimDawson (Sep 27, 2014)

nightowl499 said:


> ok looks like the extra wires are figured out turns out they do pair up to just three on a terminal strip, so here is a pick of what im fighting with anything look familiar
> 
> 
> 
> ...



The following is my best educated guess as to the purpose of the components.

Starting at the lower left are the main motor FOR/REV contactors with overload relay above. (Red Bars)

Next is the coolant pump contactor with overload relay above. (blue bar)

Next is the control power (and E-Stop) relay (yellow bar)

To the right of that is the control power transformer.

On the far right are the FOR/REV switches.

The black thing top just to right of center is the main power disconnect switch.

Having said that, the VFD will replace the FOR/REV contactors, and be controlled by the FOR/REV switches.

The VFD will be wired directly to the motor, and looks like it could be powered up through the control power relay.  It looks like the control power relay breaks all of the main power to the contactors, but I can't really tell for sure from the picture.

I hope this helps


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## mitsue (Sep 27, 2014)

*Re: vfd contactor control*

You can see in the pics that the contactors in the second picture are the original wiring that switches the motor on, off and direction. The first pic shows that the motor leads have been removed from the contactors and are now on the vfd motor output. The contactors now only switch the vfd control logic to command the drive to start, stop and reverse. This way the apron controls, e-stop, jog button and foot brake all function as original without rewiring them. The wires with red crimp on connectors are what I installed to control the drive commands.


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## mitsue (Sep 27, 2014)

JimDawson said:


> The following is my best educated guess as to the purpose of the components.
> 
> Starting at the lower left are the main motor FOR/REV contactors with overload relay above. (Red Bars)
> 
> ...



Jim's decription of the Components is correct. As for the overloads, one is the main power, another is spindle overload, and the third is for the coolant pump. I wired the coolant pump contactor to pull in only when the spindle contactors runs. 
I did however change my pump to 240v, single phase for simplicity.


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## uncle harry (Sep 27, 2014)

mitsue said:


> Jim's decription of the Components is correct. As for the overloads, one is the main power, another is spindle overload, and the third is for the coolant pump. I wired the coolant pump contactor to pull in only when the spindle contactors runs.
> I did however change my pump to 240v, single phase for simplicity.



Let me chime in and thank you for showing us your approach to the safety considerations with your solution.  Moons ago I spent serious effort designing a circuit for my M300. My machine uses 120 VAC instead of 24 but is basically similar to yours in component configuration.  Since I want to preserve the original wiring I think I will re-direct my efforts & use 2 isolating relays for FWD/REV &  parallel them with the coils of the existing F/R contactors.   This will let me isolate the low voltage F/R signals without overly disturbing the existing wiring.  

AS ALWAYS---*SAFETY FIRST*

Thanks


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## mitsue (Sep 27, 2014)

*Re: vfd contactor control*



mitsue said:


> You can see in the pics that the contactors in the second picture are the original wiring that switches the motor on, off and direction. The first pic shows that the motor leads have been removed from the contactors and are now on the vfd motor output. The contactors now only switch the vfd control logic to command the drive to start, stop and reverse. This way the apron controls, e-stop, jog button and foot brake all function as original without rewiring them. The wires with red crimp on connectors are what I installed to control the drive commands.



Additional info on my wiring:
So what I did was wire 240v to the lathe input wiring box on R (phase1), S (phase2) and earth to PE from there it goes through the machine isolating switch to the terminal strip in the control cabinet. I disconnected the wiring going from U, V and W on the terminal strip to the motor contactors. 

From the U and V I connected into the 240v input on the transfromer and also from U V and PE connected to the input of the inverter. Then connected the output 3 phase from the inverter direct to the motor and disconnected the original wiring from the motor.

I removed the input and output U, V and W wires from the forward and reverse motor contactors, I connected the common control wire from the inverter to one side of both contactors and connected the inverter forward control wire to the other side of the forward contactor and the inverter reverse control wire to the other side of the reverse contactor.

Now instead of the motor forward and reverse contactor switching the 3 phase power to the motor, they switch the control circuit for the inverter.

This way I didn't have to change any of the existing wiring for the end cover switch, brake switch, E-stop sw or Jog sw and all these functions work as they did before.


The wiring diagram is the original setup but shows the lables.
Darcy


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## mitsue (Sep 27, 2014)

uncle harry said:


> Let me chime in and thank you for showing us your approach to the safety considerations with your solution.  Moons ago I spent serious effort designing a circuit for my M300. My machine uses 120 VAC instead of 24 but is basically similar to yours in component configuration.  Since I want to preserve the original wiring I think I will re-direct my efforts & use 2 isolating relays for FWD/REV &  parallel them with the coils of the existing F/R contactors.   This will let me isolate the low voltage F/R signals without overly disturbing the existing wiring.
> 
> AS ALWAYS---*SAFETY FIRST*
> Thanks




Great safety idea for dealing the high voltage control circut. I was lucky that my contactors had 24volt coils. Isolation relays probably would give an extra level of safety on every setup.


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## nightowl499 (Sep 30, 2014)

Ok is it this simple, looks like the e stop foot break and other interlocks are all in series on the 110 leg so they should still work correctly i assume the contactors work as well just passing the 2 phase wires , so i should be able to take power for the vfd from where the main motor pwr was  , this would keep my controls the same,  disable the fw rv wires and run them to the vfd and the what was the pwr for the motor for power to vfd   does this seem  plausible on paper it looks good
thanks 
Gary


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## JimDawson (Sep 30, 2014)

I think what you describe is correct.  Just so I understand correctly, you will be controlling the VFD with un-powered wires from the existing switches.  And, will be powering up the VFD from the main contactor.  Do I have this correct?


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## nightowl499 (Oct 1, 2014)

JimDawson said:


> I think what you describe is correct.  Just so I understand correctly, you will be controlling the VFD with un-powered wires from the existing switches.  And, will be powering up the VFD from the main contactor.  Do I have this correct?




thats the way I see it, vfd powered from main motor contator  and unpowered switches from fw rv switchs  then of course three pahaswe wires to motor from vfd


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## JimDawson (Oct 1, 2014)

I think you have it.


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## Junkmaster (Jan 20, 2015)

*Thanks for the great solution....*

mitsue, 

Wow, what an elegant solution. Using the existing contactors to route the control signals. It is so simple and met my requirements perfectly. 

My requirements are to maintain all safety inter-locks (E-Stop, Foot Brake, Apron control of spindle).  I had been drawing schematics and the staring at the electrical box for a day before I found your method. I guess this head scratching made it easy to understand what you were explaining.

I have one thing that I haven't heard anyone mention.  My lathe has a 3rd contactor that acts as "spindle enable".  It controls the power to the coils on the forward and reverse contactors  for the motor. If I use the foot brake or the E-Stop, the "spindle enable" contactor is turned off, so no power can get to either the forward or reverse contactors coils.  When I return the apron lever to the stop position, the "Spindle Enable" contactor is turned back on. But, because the apron control is in the stop position, neither the forward or reverse contactor coils are energized so the spindle doesn't start. 

Also if I lose power while the spindle is running, the "spindle enable" contactor is turned off. When power is restored, the spindle doesn't start until I move the apron lever to the off position. 

Again, thanks for such a cool solution.

Evan R.


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## mitsue (Jan 20, 2015)

*Re: Thanks for the great solution....*



Junkmaster said:


> mitsue,
> 
> 
> I have one thing that I haven't heard anyone mention.  My lathe has a 3rd contactor that acts as "spindle enable".  It controls the power to the coils on the forward and reverse contactors  for the motor. If I use the foot brake or the E-Stop, the "spindle enable" contactor is turned off, so no power can get to either the forward or reverse contactors coils.  When I return the apron lever to the stop position, the "Spindle Enable" contactor is turned back on. But, because the apron control is in the stop position, neither the forward or reverse contactor coils are energized so the spindle doesn't start.
> ...




My lathe drops the contactors out when I tap the foot brake and I have to return the apron lever to off then back on to restart.  You do Not want the spindle to restart after tripping the E-stop, foot brake or after a power loss. 

Thanks for the compiments. I like to set the machines up with minimal changes to make converting back easy if needed.
Darcy


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