[wfws]

I picked up a 5hp dust collector for my CNC with a 3ph motor that connects to a power switch/controller. Looks like the controller shuts the motor down if a filter is clogged. I have a properly sized VFD to convert 220 to 3ph, and my question is: Should I connect to the controller, or go directly to the motor? I'm OK to turn it off/on using the VFD is that's best practice but I'd like to know if I need to wire it directly to the motor when power is coming from a VFD.

HOpe that question makes sense.

Wayne

[Al_The_Man]

if you want to retain the filter clogged feature, it most likely has a detector of some kind, intercept this and input it into the VFD plc inputs direct.
Incidentally any reason you are controlling a dust collector with a \VFD?

[wfws]

Thanks for the quick reply! I'm using a VFD only as a single phase to 3phase converter. So if I don't really care about the clogged filter thing I can just power the motor directly and use the VFD as the on/off correct?

[pippin88]

VFD can only supply a motor.

VFD does not generate normal 3 phase power. You can't use VFD to replace 3 phase power for a whole machine. Only for individual motor.

But usually a detector circuit will not run off 3 phase, it will be running off a single phase.

It should be:
Single phase supply -> VFD -> 3 Phase motor
Detector -> VFD digital input (you will need to know the details about the detector circuit, you can't just hook up everything to a VFD input)

Nothing between the VFD and 3 phase motor.

If you don't care about the clogged filter sensor, then yes just connect VFD to motor and remove the controller.

[Al_The_Man]

Thanks for the quick reply! I'm using a VFD only as a single phase to 3phase converter. So if I don't really care about the clogged filter thing I can just power the motor directly and use the VFD as the on/off correct?

So what form does the clogged filter sensor/controller take?
Can you give any details of it?

[wfws]

Hi- Sorry for the delay in getting back on this. I was able to take a look today. Looks like the clogged filter alarm is a separate connection, not part of the three phase connection. So I took a pic of the 3phase box with the start button.
I'd like to just wire the plug wires to the VFD 3phase outputs, but I can also bypass the start switch and wire to the motor directly looks like. Do I need these components for the motor to work? Thanks in advance for your assistance.
Wayne

- - - Updated - - -

Hi- Sorry for the delay in getting back on this. I was able to take a look today. Looks like the clogged filter alarm is a separate connection, not part of the three phase connection. So I took a pic of the 3phase box with the start button.
I'd like to just wire the plug wires to the VFD 3phase outputs, but I can also bypass the start switch and wire to the motor directly looks like. Do I need these components for the motor to work? Thanks in advance for your assistance.
Wayne

[Al_The_Man]

Looks like an amateurish installation, would have been nice to see wire No's on the conductors and terminals instead of Marettes !
May have to do some reverse engineering there to map out the existing circuit.

[wfws]

Yeah- I really like when conductors are properly labeled. So- what are the components in the box? Can I connect directly to the motor and bypass them so that the 3phase output of the VFD connects directly to the motor? Or is there some value in using these components? Thanks again for sticking with this thread.

[Al_The_Man]

You should be able to go direct from disconnect to VFD as usual, I would still look into how the clogged filter works and should be able to incorporate when the sense comes into play and either input an alarm to the system or other indication, this would allow operator to shut the spindle down in an orderly-controlled manner !
There has to be some kind of transducer that initializes the shut down.
You would also need to input the VFD start via its PLC inputs as normal.

[wfws]

Al, you are awesome! I have a couple other small projects to work on first, but I wanted to get an idea of what's involved in this. I have a pretty good idea now. The clogged filter is just an alarm that sounds- no connection at all to the motor. So if I leave that as is it will work. I still have to construct a dust bag setup and do a bit of ductwork to get it hooked up. Should be a nice improvement for my CNC router. Thanks for your great replies and assistance!