Installing a VFD to a Variable Speed Lathe Installing a VFD to a Variable Speed Lathe

What You'll Need
Variable speed lathe
Variable frequency drive
Manufacturers instruction manual

A lathe is a special electronic tool used by woodworkers, construction workers and do-it-yourselfers alike to shape wood or metal (performing actions like knurling, deformation, cutting or drilling); and most lathes today are what is known as a variable speed lathe, meaning that they can run at slow, medium or high power speeds. This allows you to have greater control over your project. These speed settings are controlled by a mechanism known as the variable frequency drive, or VFD, which is located in the lathe’s motor. The VFD channels electricity to different directions in the motor; for instance, the simplest type of VFD can turn the motor on; turn it off; and send it into reverse. If you’re becoming more skilled with your lathe work, however, you may want a more advanced VFD with different options, giving you a more fine-grained control of the machine. Fortunately, it’s a fairly simple task to install a new VFD to a variable speed lathe; just keep reading to find out how.

Step 1 – Open up the Motor

Of course, the first step to take when installing a VFD to a variable speed lathe is to open up the lathe’s motor, so that you can remove the old VFD (if necessary) and install the new one. The manner in which you go about this will differ depending on the model lathe you have, so check the manufacturer’s instructions to make sure. Basically, the procedure involves removing the casing around the lathe’s headstock by using your screwdriver to take out the few screws that connect it to the machine. Remember not to lose any of the screws for when it’s time to put the casing back on!

Step 2 – Remove Old VFD

If your lathe doesn’t have a VFD and you’re installing a new one for the first time, you can skip this step. Otherwise, remove the old variable frequency drive by simple disconnecting the wires that connect the VFD to the motor and to the motor fan. There may be 3 – 5 such wires. Unhook the wires, taking note of how the old VFD connected to them so that you remember when you install the new one. Once the old drive is completely disconnected from the wiring, remove it.

Step 3 – Install the New VFD

Attach the wires from the spindle motor and lathe fan to the VFD input and output. For most models, nothing more will need to be done, but for very advanced models you may need to tinker with the gear motor. Unless you know exactly what you’re doing, however, it’s advised that you not touch anything else so as to avoid damaging the motor; or alternatively, ask a professional to take a look. Then, screw the protective casing back on and give the lathe a test drive to make sure everything is running correctly.

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