Teco Variable Frequency Drive: Model JNEV-203-H1

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Review by barecycles posted 05-19-2012 02:37 PM 17528 views 8 times favorited 14 comments Add to Favorites Watch
Teco Variable Frequency Drive: Model JNEV-203-H1 No-picture-s No-picture-s Click the pictures to enlarge them

Now that I have been using this VFD for a few weeks I thought it might be time to post a review of it.

The sole reason for purchasing this product was to power the 3 phase motor on my Unisaw given that I only have single phase power at my location. I looked at alternatives like a Rotary Phase Converter, a Static Phase Converter or even swapping out the 3 phase motor for a single phase motor but I wanted to experience the full power this motor offered. So, in the end I opted for the VFD and in particular the JNEV-203-H1. I selected this model on the advice of the knowledgeable folks over at Practical Machinist. In short, the EV models offer 3 wire controls natively while other Teco models require some compromise to do that. The cost was $215 from dealerselectric.

Prior to purchasing this product I did a fair amount of research because it seemed most folks were a little intimidated if not frightened about the prospect of running their equipment off these devices. Also, many were confused about the wiring and settings on their VFD’s. I’m sure I would have been too if I had not read about the mistakes and successes of others and took the time to understand the manual before even thinking about setting it up. Just verify that you have a VFD that is rated for the motor’s HP. Mine is 3 HP so I got the 203 which is rated for 3 HP.

Set up was really quite painless. I did a quick bench test while I already had my motor pulled from the saw cabinet. And really, if you can wire a light switch, you can wire this box as well. It is just a matter of bringing in your 240 volt 3 wires (2 hots and a ground, your neutral is not needed) to the VFD terminals L1, L3 and PE. Then off the VFD terminals T1, T2 and T3, run your wiring directly to your equipment’s motor. It really needs to be a direst connection, no switch or anything in between.

Next, power up the VFD and see that you have voltage. The drive is defaulted to initially run at 5 Hz. Then press the run key on the VFD and note the motor direction. If it turns the wrong direction you can swap T1 and T2. Once you’re satisfied with the direction change the frequency to 60.

That’s all there is to testing it. The rest of the settings all deal with preferences. For instance, I have set my acceleration time to 10 seconds (default was 5) and deceleration to 10 (again default was 5). You can set it to coast to a stop or specify how quick you want it to stop. There are a lot of options you can select and they are all explained in the manual.

This brings me to the only downside of the whole experience. I don’t think the manual is difficult to understand but it is small, as is the print. You can see in the picture about the size compared to the CD that comes with the device. Thank goodness for the CD! It also contains a manual and once printed out is a lot more readable.

You will notice I have my VFD mounted to the wall a few feet from the saw without any enclosure. Again, advice from the folks at Practical Machinist really doesn’t advise enclosing it although you can. Just make sure you following the specs in the manual to allow for adequate air flow. Heat is not your VFD’s friend. Since I have a good dust collection system I just hit VFD with a puff of compressed air on occasion and it stays clean.

I installed a motor switch between the VFD and my service panel just to keep from having to flip my breaker when I wanted to kill power to the VFD.

I was able to use the original ON/OFF switch on the saw to control power to the motor as the VFD has low voltage terminals to control it remotely. Those are the small wires exiting the bottom of the box in the picture. I think I just used sprinkler wire for that. This is a lot better, not to mention safer, than trying to hit a little button on the face of the VFD while the saw blade is spinning.

Well that’s it! I have been very satisfied with this product and may revisit this review at some point down the line after it has been in use to review its durability.

-- Sweeping up sawdust in Texas

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256 posts in 2046 days

14 comments so far

View tblank's profile


61 posts in 2688 days

#1 posted 05-19-2012 02:47 PM

Thank you for your insightfull review. Been wondering about these for awhile. Seems a good price as well comparatively.

View Bruce C.Oestreich's profile

Bruce C.Oestreich

25 posts in 2097 days

#2 posted 05-19-2012 03:14 PM

Yes VFD is the way to go.My friend has a metal working 3 phase band saw which he installed a Vfd.He has used it for several years and gives excellent performance.There are still a lot of 3 phase motors out there that are relatively inexpensive that can be converted to woodworking machinery without being machine specific . thanks for the insight. Bruce

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13128 posts in 2411 days

#3 posted 05-19-2012 03:21 PM

Great review! Takes a bit of the mystery out of these for me.

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

View sikrap's profile


1121 posts in 3077 days

#4 posted 05-19-2012 06:56 PM

I have a similar VFD for my 3 phase Delta jointer and its great. One other benefit is that if you install a twist lock plug somewhere between the machine and the VFD, you can start looking at other 3-phase machines and they are generally MUCH less expensive than single phase.

-- Dave, Colonie, NY

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Don W

18411 posts in 2285 days

#5 posted 05-19-2012 07:38 PM

So could you wire multiple machines, or would you have to unplug and plug the different machine into it?

Thanks for the review. I’ve always tended to avoid 3 phase machines for the obvious reasons, although they seem not so obvious now.

-- - Collecting is an investment in the past, and the future.

View MedicKen's profile


1610 posts in 3180 days

#6 posted 05-19-2012 08:55 PM

I absolutely love 3ph machines. I have 3 VFD’s now and they work wonderfully. The best application is for either a drill press or lathe where you can utilize the variable speed capabilities. I dont think I will ever go back to single phase. Nice review of the VFD, all of mine are the entry level FM50’s and I have not had 1 issue with any of them. I have also found that has a little better pricing than delaerselectric.

-- My job is to give my kids things to discuss with their

View barecycles's profile


256 posts in 2046 days

#7 posted 05-19-2012 09:28 PM

MedicKen: I agree. It makes me want to go out and buy a big honkin’ lathe so I can fully use the capabilities of the VFD

Don W: The short answer is yes and no…sorry, I know that’s vague. Below is what the guys over at OWWM say about it:

If you mean turning on and off two motors at the same time, the answer is yes. Just hook them up in parallel.

If you want to have two or more devices turn on and off at will then the answer is maybe.

I wrote a PLR (Programmable Logic Relay) program earlier this year so that one could safely share a VFD between machines. I was done in about 4 hours.

The constraints to switching a VFD’s output are formidable when one tries to use just contactors and switches to handle the switching. Here are the constraints as I see them.

The output of the VFD must be connected to the motor before the VFD is told to turn on the motor.
The VFD must be told to turn off and braking completed before disconnecting the motor from the VFD.
Once a motor or motors are selected and the VFD turned on, no other motor may be connected to the VFD’s output. In other words a lockout must occur.
The fwd/rev, start/stop, and variable speed controls must be switched from station to station.

-- Sweeping up sawdust in Texas

View b2rtch's profile


4843 posts in 2766 days

#8 posted 05-20-2012 10:34 AM

I do not mean to hijack this post but be careful before you go buy a VFD.

I wanted to do the same thing at home but at work just about all our equipment is on VFD and I was told that all motors do not work properly with a VFD, they must be inverter duty if not they will burn out.
Because, in addition to other things, with a VDF a normal electric motor can be run very low rpm and at full load, it does not get enough cooling.
I hope this help.

From :

How to choose a general purpose motor vs. an inverter-duty motor
General purpose motors have been around for many years. They are the workhorse of almost every industry. An inverter-duty motor is a much newer concept that became necessary as motors began to be driven by VFDs (inverters or AC drives). An inverter duty motor can withstand the higher voltage spikes produced by all VFDs (amplified at longer cable lengths) and can run at very slow speeds without overheating. This performance comes at a cost: inverter-duty motors can be much more expensive than general purpose motors. Guidelines for choosing an Ironhorse general purpose motor vs. an inverter-duty motor are given below. If your application falls within the guidelines below, there is no need to apply an inverter-duty motor.
NOTE: Marathon inverter-duty motors have limitations as well. Please see the Marathon section for more details.
Background: AC motors can be driven by across-the-line contactors and starters. The electricity sent to the motor is a very clean (true) sine wave at 60Hz. Noise and voltage peaks are relatively small. However, there are drawbacks: the motors can only run electrically at one speed (speed reduction is usually handled by gearboxes or some other, usually inefficient, mechanical means) and the inrush of electrical current (when the motor is first turned on) is usually 5 to 6 times the normal current that the motor consumes. The speed reduction apparatus is expensive and bulky, and the inrush can wreak havoc with power systems and loading (imagine an air conditioning system in an old house – when the compressor kicks on, the lights dim; now imagine the same circumstances with a motor the size of a small car).
Note: The following discussion applies only to 3-phase motors.
Enter the VFDs (variable frequency drives):
Drives were introduced to allow the speed of these motors to be changed while running and to lessen the inrush current when the motor first starts up. To do this, the drive takes the incoming 60Hz AC power and rectifies it to a DC voltage. Every drive has a DC bus that is around 1.414 (sqrt of 2) * incoming AC Line Voltage.
motor base chart

This DC voltage is then “chopped” by power transistors at very high frequencies to simulate a sine wave that is sent to the motor. By converting the incoming power to DC and then reconverting it to AC, the drive can vary its output voltage and output frequency, thus varying the speed of a motor. Everything sounds great, right? We get to control the frequency and voltage going out to the motor, thus controlling its speed.
Some things to watch out for:
A VFD-driven general purpose motor can overheat if it is run too slowly. (Motors can get hot if they’re run slower than their rated speed.) Since most general purpose motors cool themselves with shaft-mounted fans, slow speeds mean less cooling. If the motor overheats, bearing and insulation life will be reduced. Therefore there are minimum speed requirements for all motors.
The voltage “chopping” that occurs in the drive actually sends high-voltage spikes (at the DC bus level) down the wire to the motor. If the system contains long cabling, there are actually instances where a reflected wave occurs at the motor. The reflected wave can effectively double the voltage on the wire. This can lead to premature failure of the motor insulation. Long cable lengths between the motor and drive increase the harmful effects of the reflected wave, as do high chopping frequencies (listed in drive manuals as carrier frequencies). Line reactors, 1:1 transformers placed at the output of the drive, can help reduce the voltage spikes going from the drive to the motor. Line reactors are used in many instances when the motor is located far from the drive.

Effect of a Line Reactor on the Waveform

In summary, general purpose motors can be run with drives in many applications; however inverter-duty motors are designed to handle much lower speeds without overheating and they are capable of withstanding higher voltage spikes without their insulation failing. With the increased performance comes an increase in cost. This additional cost can be worth it if you need greater performance.

-- Bert

View klassenl's profile


175 posts in 2377 days

#9 posted 05-20-2012 06:50 PM

Yep, technology is great.

You don’t need and enclosure for it, but the code but would ask that all wiring that is not contained within a cable sheath, raceway, etc. to be in a metal box approved for such a purpose. However, if you saw my shop you wouldn’t think that it belonged to an electrician that was familiar with code.

Be safe.

-- When questioned about using glue on a garbage bin I responded, "Wood working is about good technique and lots of glue........I have the glue part down."

View barecycles's profile


256 posts in 2046 days

#10 posted 05-20-2012 09:49 PM

Bert makes a valid point about speed and the cooling aspect of the motor. The Baldor motor on this Unisaw was designed to spin at 3450 RPM, 60 Hz for a reason. I refrain from increasing the speed for fear of ruining the bearings at higher speeds. Likewise, running too slow places the motor in jeopardy of overheating. According to the experts (I use that term very loosely) I hang around, these AC motors should never be run at less than 75% or more than 125%. The VFD is set at 60 Hz to run my saw and I don’t see any reason to deviate from that.

Now, there is another aspect of bearing failure that can occur in a VFD driven motor. The voltages that can build up on the motor shaft will likely be discharged to the bearings causing small pitting that progressively gets worse over time. I’m not familiar with this situation happening on a VFD controlled Unisaw motor but I have experienced it elsewhere.

-- Sweeping up sawdust in Texas

View hhhopks's profile


650 posts in 2095 days

#11 posted 05-26-2012 01:28 AM

Thanks for the education and enlightenment.
It is amazing how computer/electronics works.

-- I'll be a woodworker when I grow up. HHHOPKS

View cigale's profile


1 post in 1807 days

#12 posted 09-05-2012 08:08 PM

Hello, a new question for an old topic.

As I just ordered a VDF, I was wondering if the motor needs to be grounded aslo?
I see you only connect the 3 phase cables to the motor.


View vweaver's profile


1 post in 766 days

#13 posted 07-13-2015 07:33 PM

Now that you’ve had 3 years (? assumption) under your belt, do you still feel the VFD was(is) the way to go?

View barecycles's profile


256 posts in 2046 days

#14 posted 07-14-2015 11:26 AM

vweaver: Yes, the VFD is still going strong, I have been using it regularly and I have not had any issues with it. Now, other things in my shop have bit the dust but not this item.

-- Sweeping up sawdust in Texas

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