From scratch wiring for mill with VFD?

Hello all- first post here, but I've been lurking for a couple weeks. I've learned a great deal already from reading old posts, thanks for that!

Anyway- some background:

1. I've just gotten my first mill/drill, an original RF-30, 3 phase, 240v, 2 speed motor: 2hp, 1640 rpm, 6.3 amp, 4pole or 1hp, 820rpm, 6.4 amp, 8 pole.

2. I have purchased a 2hp Teco EV Single phase input VFD.

3. I have tested the VFD on the mill with some temporary wiring, and it works well, other than some vibration at certain speeds. This may have been caused by broken connections in the motor junction box.

4. All of the original wiring and controls were 'suspect' due to prior modifications and damage. They have all been removed.

Now, my questions:

1. I wish to wire the motor for higher speed, but the label in the motor junction box leaves something to be desired (particularly clarity). It appears that I should connect 1,2,3 together, and connect 4,5,6 each to one of the inputs from the vfd. Does this seem accurate?

2. I intend to mount the vfd on the wall behind the mill, as it seems too open to be near the swarf, and run a set of low voltage controls on the head. I have NO muscle memory as this is my first mill, so I wonder what is the optimal set of controls? Three Fwd, Stop, Rev buttons, plus a speed control pot, or a drum switch plus the pot, or Stop/Run buttons with a direction switch, etc, etc...

3. I want an E-stop that kills everything, including the VFD. I would prefer if it had multiple button locations. Is this accomplished with a contactor on the VFD input?

4. The VFD continues to run when the power is disconnected. Can I make use of this fact to tell the VFD to brake the spindle at maximum rate, using external resistor if one is fitted? ( I want the E-stop to actually mean something )

Thanks for any help or pointers you can provide.

allan

Be sure to look at the files on the CD rom that comes with the VFD. The paper
manual is incomplete, there are vital bits of information left out of the paper manual
including the wiring details for the various schemes.

My approach (being set up on a pratt whitney bench miller) is a speed control
pot, and a single pole, two throw, center off toggle switch. This gives the
fwd/off/ref control.

You can wire it "three wire" which is two momentary buttons, start/stop with a
toggle switch for reverse if you desire.

The BRS (big red swich, AKA EMO, AKA emergency off) is typically implemented
in logic, and I think you can do this by either paralleling multiple buttons, or seriesing
them, depending the the wiring setup. The CD rom manual goes into this I think.

There may be a need to choose one particular logic scheme, I forget if it is active
high, or active low, to achieve the easiest hardware OR function for the various
EPO switches. Active high being the logic inputs return to logic B+ in the VFD,
active low where they return to ground instead. There was a poster here who
just recently (within the last few months) went through this drill.

Strongly suggest it is not really necessary to shut down the power input to the
VFD when operating the EPO button. It's pretty much industry standard to rely
on the logic controls to stop the spindle this way.

I used a Teco FM50 for my mill this is how I wired it up works like a champ.



Marci

Jim- Thanks for the heads up on the other manual, the paper one is a bit sparse. I must say I am surprised that the safety guys in industry are comfortable with using the 'soft' E-stop in the VFD. I am sure that these machines are quite reliable, but I have particularly bad luck I would prefer to do both, have the vfd engage the brake for as long as it's caps last, while pulling the mains out at the same time.

Marci- very helpful diagram, but two questions: 1. are you using the E-stop features of the FM50, or just the contactor (does it take awhile to spin down?) 2. the fwd/rev switch is NO? is there a separate 'non-emergency' stop?

All- It appears that the 2 speed wiring I described is correct for a parallel wye, delta motor, which I assume is what this thing is.

Thanks!

allan

The reason...

Allan-

The reason why industry is satisfied to use the Estop in logic, rather than chopping power to the VFD, is that most ESTOP conditions are for either mechanical or human/operations problems rather than drive failures.

Since the VFD has dynamic braking ability, the machine will stop faster than if the drive was simply disconnected from mains.

Most VFDs have substantial fault detection within, and will Estop to the best possible result upon finding internal faults.

kitno455 said:

Jim- Thanks for the heads up on the other manual, the paper one is a bit sparse. I must say I am surprised that the safety guys in industry are comfortable with using the 'soft' E-stop in the VFD. I am sure that these machines are quite reliable, but I have particularly bad luck I would prefer to do both, have the vfd engage the brake for as long as it's caps last, while pulling the mains out at the same time.

Marci- very helpful diagram, but two questions: 1. are you using the E-stop features of the FM50, or just the contactor (does it take awhile to spin down?) 2. the fwd/rev switch is NO? is there a separate 'non-emergency' stop?

All- It appears that the 2 speed wiring I described is correct for a parallel wye, delta motor, which I assume is what this thing is.


Thanks!

allan

Click to expand...

If you look closely at the schematic the emergency stop (big red button) is in the primary circuit of the transformer, once pushed all power to the FM50 and everything else is removed. E braking is programmable in the FM50 and activates automatically when the on/off--forward/reverse switch is in neutral (stop) position. Depending on how the programing features are set the spindle can be made to stop almost instantaneously.

Marci