I am in the process of converting a Harrison M250 from 3 phase to single phase operation via an Ecogoo 380 volt VFD and will be keeping as much of the control panel as I can original except for the addition of a digital tacho and potentiometer for the VFD. Over the last few days I have made a bracket to mount the inductive proximity sensor and fitted a gear directly over the end of the spindle for the sensor to detect.

I was eager to give it a test run today even though the control panel is not ready and the VFD is not mounted in an enclosure, I think it works great and responds to speed changes faster than other tacho installations I have done where I only used 6 or 8 pulses per revolution, this gear has 42 teeth. I may be able to reduce the 4 second VFD acceleration time down a bit as well.

IMG 6512 1 - YouTube


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