Unisaw #3: VFD bench testing 3 phase 3HP

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Blog entry by barecycles posted 03-24-2012 11:00 PM 4811 reads 0 times favorited 5 comments Add to Favorites Watch
« Part 2: Slowly but surely Part 3 of Unisaw series Part 4: External control decided. Vibration found. »

The VFD I will be using for this saw is the Teco JNEV-203-H1. As a first test I wanted to test everything on the bench. I have temporarily setup a 30A breaker and wired the 2 hots to the VFD terminals L1 and L3, the common ground to the VFD terminal PE and capped off the neutral lead.

From the VFD terminals T1, T2 and T3 I ran wire to the motor leads 9 wire setup. The only functions I have set are the frequency (60 Hz), accel time and decel time (both 10s).

I’m a little surprised at how quiet the motor is. Most of the noise in the video is from the VFD fan. My next step is to add my remote controls as I don’t plan on using the keypad to control things. Once that is done the motor goes back in the cabinet with new belts and I’ll try to decide where I want to place the saw in the workshop. I’m debating using an existing 50A breaker in my main panel to feed a sub-panel that will supply power to the saw and a couple of other tools. But that will have to wait, I’ve basketball to watch!

-- Sweeping up sawdust in Texas

5 comments so far

View exelectrician's profile


2328 posts in 2509 days

#1 posted 03-25-2012 03:08 AM

You are one of the few who have the courage to go with a VFD – Good for you! You will discover a whole raft of benefits when you start experimenting with various speeds, also experiment with the DC braking feature to get the motor to stop in 1 – 2 seconds, be careful with your current setup. The huge torque developed in quick stops and starts will make an unmounted motor roll around your shop like a demented thing! So bolt that sucker down to something ten times what the motor weighs, better still mount it in the saw frame, then you can go to town seeing what the limits are in accel and dynamic braking.

-- Love thy neighbour as thyself

View barecycles's profile


257 posts in 2410 days

#2 posted 03-25-2012 04:09 AM

Thanks! Yeah I’m pretty stoked about the possibilities. And it’s funny you mentioned my unmounted motor. My son and I were talking about just that. He wanted to do a quicker stop and I thought better of it until I have the thing anchored down to something.

-- Sweeping up sawdust in Texas

View b2rtch's profile


4862 posts in 3130 days

#3 posted 05-15-2012 11:46 AM

I work with VFDs at work.
I do not fully understand the advantage of a VDF on a table saw as I believe that you want the blade to always spin as fast as possible , no?
.What I would like on my Unisaw is a soft start. ( I know that can be done with a VFD but it should be possible to do it in a simpler and cheaper way).

-- Bert

View Bertha's profile


13529 posts in 2775 days

#4 posted 05-15-2012 12:09 PM

^I’d really love a soft start feature, too. I used to be shy admitting this, thinking it was too much of a luxury. But after putting a soft-start router in my router table, I really like the feature. My old JET springs to life at top speed. Sounds terrifying.

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

View b2rtch's profile


4862 posts in 3130 days

#5 posted 05-15-2012 12:19 PM

Not only that but the sudden full load on the belts and bearings cannot be good.

I Just talked to a technician who told me that the older motor on the Unisaw cannot be controlled by a soft start. We have the same issue at work with VFDs.

-- Bert

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