Nova 1624 – adding variable speed – Remote Box

By Steve Harder


My goal was building a small remote box that could be positioned at the tailstock or bed area of the lathe (magnets epoxied to back of box). The box would control Run/Stop, Fwd/Rev and speed. Most VFDs provide for connection of a remote box. And the wiring and setup are usually similar. My VFD is a GPS2 – details are in my previous article on motor and VFD install, links:

Parts list:
2 060-590 SPST Heavy Duty Paddle Switch $2.28 $4.56
1 320-712 Hammond 1591GSBK ABS Project Box Black $5.11 $5.11
1 023-628 10K Linear Taper Potentiometer 1/4" Shaft $1.55 $1.55
1 Knob @ Radioshack
25 ft 6 conductor cable (I had some on the shelf) – any 18gauge cable should work
6 pin connector (trailer hitch light connector)
1 Emergency stop switch (optional)(leftover from previous lathe wiring setup)

Cable run starting at VFD:
From VFD: 3 ft of cable into 6 pin disconnect (so motor and VFD and be removed from lathe)
From disconnect: cable runs to Emerg Stop switch.
From Emerg Stop: cable runs to remote box (yellow wire is passed thru Emerg stop switch).

I used a graphics program to print label for front of box, and then used label to position and drill holes for switches and pot. Knob is labeled with Hz – the safe range for my motor is from 30 to 90 but I can run between 0 and 30 for short periods of time. The VFD displays approx lathe rpm.

Then I hooked up the wires. Pics pretty much tell the story.

On my remote box the switch is On when handle is up.
Left switch ON connects yellow wire (D1) to brown wire (DCM) and VFD “runs”.
Right switch ON connects light blue wire (D2) to brown wire (DCM) and VFD “reverses”.

Red wire provides +10V to pot, white wire provides “common” to pot, green wire returns variable voltage to VFD.

You will need to change several parameters in the VFD.

Parameter 3.00 set to 01 “Operation determined by external control
terminals. Keypad STOP is enabled.”

Parameter 3.01 set to 01 “DI1 - RUN/STOP DI2 - REV/FWD”
(You could also use a momentary run/stop switch if you have one of those sitting around – you just set this parameter to a different value.)

Parameter 4.00 set to 02 “frequency determined by 0 to +10V input (including
remote potentiometer) on on AI terminal. Switch SW1 must be set to AVI.

The remote box was really the icing on the cake in the VFD conversion. I didn’t realize how much I’d like having control of the lathe over at the tailstock area, so I don’t have to cross the “line of fire”.