Can use a vfd on my mill with the original buttons?

[Nolyplayz]

I have a santec bed mill it has a 220/440 3hp 3phase motor. I got a vfd for it to go from single phase to three phase. I think I have all of the settings right but it is not working. Based off my research everyone wires their buttons to the vfd as an input, so I was wondering if I can use the original controls on the machine, and just hook the mills original power cord to the vfd. Or do I need to hook the vfd directly to the motor and wire the buttons to the vfd.

 

[CalG]

I have a santec bed mill it has a 220/440 3hp 3phase motor. I got a vfd for it to go from single phase to three phase. I think I have all of the settings right but it is not working. Based off my research everyone wires their buttons to the vfd as an input, so I was wondering if I can use the original controls on the machine, and just hook the mills original power cord to the vfd. Or do I need to hook the vfd directly to the motor and wire the buttons to the vfd.

The latter arraingement is the case. The buttons must open and close control switches in the VFD.

 

[JST]

That's the only way it can work unless you drastically over-size the VFD.

With the system you describe, using the switches to connect and disconnect the motor for start and stop, the VFD needs to supply the starting current of the motor, which can be 7 times the full load current.

 

[Nolyplayz]

So would a phase converter work with the original controls.

 

[JST]

An RPC would be fine with them. All it does is make 3 phase from single phase, and it involves no solid-state parts that have hard current limits.

 

[Overland]

You should be able to use your original buttons.
You must wire the power side of the VFD directly to the motor.
The buttons you refer to are probably momentary. In which case you can consult VFD instructions and:
- use the "ON" button to send a pulse directly to the control circuit on the VFD.
- internally the VFD will "latch" this command on
- the "Off" button is usually a "normally closed" button; when you press this button, the latch will drop out and the VFD will stop.

In this way, you must eliminate al the old contactors, etc from the circuit. You must program the VFD to operate using the Function codes.
It's really quite straight forward.
Fuji Frenic-mini has this feature; and this one below will support a 3 hp motor as you require.
Bob

VFD, 5hp, 19.1A, 230VAC, 3 Phase Input, Compact Mi

VFD, 5hp, 19.1 Amp (19.1A), 230VAC, 3 Phase Input, Compact Micro Drive, Easy To Use, IP20 UL Open Type, 7.09 x 5.51 x 5.47" (HWD), Optional NEMA/UL 1 Kit: NEMA1-C2-301 and Optional DIN Rail Mounting Adapter: RMA-C1-3.7 Available to Order Separately, Constant Torque (CT) Rated, FRENIC-Mini Series

www.wolfautomation.com

 

[cryptopsy1]

Can I use one VFD to power a milling machine which has 2 motors like the deckel euromills? It has one motor for spindle and another for feeds. Plus the coolant pump.

 

[JST]

Assuming all motors are 3 phase, if it is oversized, and you don't use speed control, yes, in most cases.

If the other motors are single phase, you have no problems. Run them from the incoming power.

Otherwise an RPC is what you want, probably. Or more than one VFD.

 

[laminar-flow]

Here is my method on a Deckel FP-1.

Deckel FP-1 VFD conversion keeping the original electrical panel

Having recently lost my phase perfect solid state converter, and the new phase perfect not running the unique Deckel motor correctly, my son and I looked into converting to a single VFD. We wanted to keep the original Deckel functionality and the electrical cabinet, but how with a two speed...

www.practicalmachinist.com

 

[rons]

If you are going to be doing this kind of work a lot:
Setup for both a VFD and a RPC. Maybe not at the same time but sooner or later one of them will have a problem or repair or upgrade.
Then you have something to fall back on. I use both. Another way to think about it. If your heart depended on a VFD or RPC, which would you use.
I whole heartily approve of the RPC.