Ecogate controller with VFD contolled machines

[Joe Jensen]

I've been using an Ecogate automatic dust collection system for about 5 years and I love the automation. The system senses a tool's motor running, opens the appropriate blast gate, closes the others, and then runs the collector. Once the tool shuts down, the collector continues running for the length of time I programmed in. Life was great until I added a jointer with a VFD. The VFD generates a lot of electical noise and that was confusing the controller. I worked with Ecogate and tried a number of things over the past 14 months and nothing worked. New wires, different wires, better shielding, ferrite core chokes, etc. Their end recommendation was a new commercial controller and all new sensors which would have cost me upwards of $1500

I decided to try to make my own sensor circuit so I called and asked their engineer about the input requirements of their controller. He gave me what I needed and then asked why I was going to make my own when they already had one.

Pretty amazing as this is the same guy who sent me off on all the other potential fixes.
SO, for those of you who may have an Ecogate and need it to control a VFD based machine, here is what you do.
1) Buy the sensor simulator board from ecogate. It is $21. When circuit on the board is closed, the board generates a 100mV AC signal which is what the Ecogate 8 gate controller wants to see. I will close that circuit by wiring a small relay on the machine. the relay will connect to the VFD so that when the VFD is active, a circuit closes. This will turn on the Ecogate sensor simulator, and that will turn on the controller, open gates, and run the collector.

I'll report back after I have one of the three machines working this weekend (assuming the boards arrive).

[David DeCristoforo]

Just put your current sensor in a junction box before the VFD. As long current is passing through the wire when the machine is on and no current is passing through the wire when the machine is off, the sensor should not care where in the circuit it is. Technically, you could even put the sensor in your service panel as long as it's a dedicated circuit that will not be activated by other machines.

[Joe Jensen]

Just put your current sensor in a junction box before the VFD. As long current is passing through the wire when the machine is on and no current is passing through the wire when the machine is off, the sensor should not care where in the circuit it is. Technically, you could even put the sensor in your service panel as long as it's a dedicated circuit that will not be activated by other machines.

Tried that on the jointer. Apparently there is enough EMI and my electicatl panel is only 6 ft from the machine. With my Felder I have one power cord are two different machines so that tool needs a solution like this anyway.

[Alan Schaffter]

My autogates work fine with my VFD, almost. My system uses current sensor switches (small torroid coil + transistor) at each outlet. They operate 24V pneumatic solenoids. The solenoids port shop air, regulated to 15 psi, to cylinders mounted on each blast gate that open and close the slide.





The problem I have with the VFD (on my drill press) is that when the VFD is powered up via the start/stop buttons, the blast gate opens momentarily then closes due to the initial current surge. After that, the gate opens and closes normally when I select run/stop with the small remote toggle switch (below the red knob for the speed pot).