Tool Reviews: Teco FM50 Variable Frequency Drive

This video is a more in depth application of the controls for this machine I’ve shown in previous videos. In it I show how I installed and configured this variable frequency drive to provide both 3 phase power to the motor as well as add some features as well.

It’s worth mentioning something I didn’t want to cloud this particular video with and that is speed control. A jointer does not need speed control and can run at full motor RPM but for machines like a drill press or lathe, a VFD might be used primarily for speed control and some additional IO. The VFD gives you such a wide range of speeds as it varies the frequency and voltage to the motor. A pot or knob can be added as an input to these or you can purchase versions or kits with them to give you ultimate control of your motor.

Also, while ideal, a local circuit breaker at the machine and the rotary disconnect are not required to make this work. It’s probably overkill for most people, but the circuit breakers in your home are far inferior to these MCBs that offer better protection specific to the type of load. A disconnect could be replaced with a simple light switch too, any way to denergize the unit. Keep in mind that you should never put a switch in series with the motor output, and that you should only use the low voltage inputs for controlling the output of the VFD.

Bill of Materials:

Teco VFD:

Rotary Disconnect:,_UL_508_Rated_Non-Fusible_Disconnects/DIN_Rail_or_Panel_Mount_(16-40_Amps,_SD1_Series)/SD1-025-BR

(You will want to size this to the branch circuit, just don’t cut it close on the circuit load, when in doubt size it larger than you need.)

Rotary Disconnect Handle:,_UL_508_Rated_Non-Fusible_Disconnects/Handles_-a-_Shafts/SD-HRY

Rotary Disconnect Shaft:,_UL_508_Rated_Non-Fusible_Disconnects/Handles_-a-_Shafts/SD-S300

(Just get the longest one they have and cut it to size once you get everything mounted in the enclosure.)

Aluminum Slotted Din Rail:,_Clips_-a-_Brackets/DN-R35SAL1-2

Circuit Breaker: You really do not need to do this as the VFD has internal protection but if you want to just go with any MCB (Miniature circuit breaker) That is din rail mount and mount it next to the disconnect, 2 Pole, sized with accordance to circuit load/demand).


(Note: Any metal box will do and don’t be partial to this one, I chose it because it is inexpensive and fits the VFD perfectly. Do size it to the one you purchase though as these come in different depths and you may need a larger box or get away with a smaller one)


To see my Powermatic 8″ Jointer Restoration Videos:

Factory Mation’s brief overview on the Teco VFDs:

Great technical writeup on how VFD’s work:

A good place to buy Teco VFD’s, DIN Rail, Disconnects and Circuit Breakers:

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