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Help with UniSaw motor

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Forum topic by SweetTea posted 06-08-2017 12:37 PM 734 views 0 times favorited 14 replies Add to Favorites Watch
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SweetTea

248 posts in 499 days


06-08-2017 12:37 PM

Hey guys, I finally picked up the old Delta/Rockwell UniSaw that I purchased a couple of weeks ago, and I need some help with either replacing the 3 phase motor with a single phase, or purchasing a pre made VFD or Rotory Phase Converter. I have attached some pics of the motor, motor plate and cabinet. This is a Rockwell 34-450. I have no idea how old this saw is, I am planning on doing a full restore, starting with the motor.

I posted a thread a while back, before I picked it up, and there were some good responses but I was told that without a pic of the motor plate, there wasn’t much I could do. So here are the pics. I would appreciate any links and advice on buying either a VFD type of thing or a new single phase motor. Thanks in advance for the help fellows.


14 replies so far

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SweetTea

248 posts in 499 days


#1 posted 06-08-2017 12:39 PM

More pics

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MrUnix

6012 posts in 2038 days


#2 posted 06-08-2017 05:20 PM

I have no idea how old this saw is

The serial number should tell you what year it was made.

As for the VFD… that motor has an FLA of 7.4A, so the “2hp” Teco (Westinghouse) drives would work just fine (rated at up to 7.5A). Either the L510-202 , which can do either V/Hz or sensorless vector control, or the cheaper V/Hz only FM50-202 (which is what I have on mine). You can get more expensive drives from other manufacturers, or cheaper no-name import brands from the bay – Although the cheaper ones seem to be a hit-or-miss proposition and most lack support.

Going with a VFD, you can remove/ignore the existing LVC starter, but still use the existing control station (start/stop buttons) on the machine to control the VFD.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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SweetTea

248 posts in 499 days


#3 posted 06-08-2017 05:37 PM


I have no idea how old this saw is

The serial number should tell you what year it was made.

As for the VFD… that motor has an FLA of 7.4A, so the “2hp” Teco (Westinghouse) drives would work just fine (rated at up to 7.5A). Either the L510-202 , which can do either V/Hz or sensorless vector control, or the cheaper V/Hz only FM50-202 (which is what I have on mine). You can get more expensive drives from other manufacturers, or cheaper no-name import brands from the bay – Although the cheaper ones seem to be a hit-or-miss proposition and most lack support.

Going with a VFD, you can remove/ignore the existing LVC starter, but still use the existing control station (start/stop buttons) on the machine to control the VFD.

Cheers,
Brad

- MrUnix

Would the correct model be the Teco FM50-202c or the FM50-202 N4FS?

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MrUnix

6012 posts in 2038 days


#4 posted 06-08-2017 05:42 PM

Would the correct model be the Teco FM50-202c or the FM50-202 N4FS?
- SweetTea

They are both identical except for the enclosure… NEMA 1 (IP20) or NEMA 4X

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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magaoitin

246 posts in 788 days


#5 posted 06-08-2017 06:52 PM

I bought the Teco FM202-C a few months ago ($170) and have nothing but great things to say about it. I bought it for a 3 phase bandsaw so that I could have the option of variable speed, but in your case you can crank it up to the full 60 hz and leave it there.

It is literally as simple as taking your shop’s 240v power and putting the 2 wires into the VFD and them the 3 wires directly from your 3 phase motor to the VFD, bypassing the motor starter and Thermal Overload breakers, and now the VFD controls the motor. Add 2 wires from your on/off switch to the VFD and your factory on/off switch works.

The FM-2020 has a built in 12VDC power supply for external switches (and you can even hook up a remote potentiometer, neat for a variable speed bandsaw, but nothing you would need to worry about).

Since the instructions are not that clear form the factory I contacted TECO and this is what their tech sent me on wiring the ON/OFF switch

Your “OFF-ON” selector switch should be a Normally Open Dry Contact. You would wire one terminal from the Dry Contact to Terminal 5 (12V) on the TM2 Terminal Block. The remaining terminal from the Dry Contact would be wired to Terminal 3 (FW) on the TM 2 Terminal Block.

You need to put some though into where you are going to mount the VFD (that I did not realize when I bought mine.) If you just mount it on the wall next to your saw you are going to have 2 wires coming out of the wall for the incoming 240v power, then a minimum of 3 wires from your saw motor to the VFD, (2 more if you hook up the on/off switch.) The same is true if you mount the VFD to the outside of the cabinet. I really need to mount mine inside a bigger box (NEMA enclosure) to protect the wires and clean it up. I don’t like bare wires just hanging out on the wall.

If you mount it inside the Saw cabinet so it is all hidden, well that is a very dusty environment and the manufacturer recommend using a NEMA enclosure to mount the VFD in, but then you have the issue of heat build up and space on the VFD. TECO sells a power ventilated enclosure, but it is more expensive than the VFD, and now you are in the neighborhood of buying a new single phase 2 hp motor.

It’s hard to tell from the photos but it looks like your motor is a 230v and not a 460-480v, which makes it simple. I had to rewire my motor from 480v to 240v so that the FM-202 would work. The FM-202 only works on 220v-240v motors.

Good luck and post some pictures

-- Jeff ~ Tacoma Wa.

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MrUnix

6012 posts in 2038 days


#6 posted 06-08-2017 11:39 PM

Just a couple comments about the info Jeff gave above…

To wire it up, you will need 3 wires (hot-hot-ground) from the supply, not two… and there will be four wires from the VFD to the motor… it is very important to have the grounds all connected.

Also, the way he (and the tech) describes the on/off switch wiring is correct if you are using a standard toggle type switch (SPST on/off switch), but not for the momentary switches you have on that Unisaw (NO Start, NC stop). For that situation, which is referred to as ‘three-wire’ control, you hook it up like the following:

For the FM50:

For the L510 (you can ignore the fwd/rev switch):

And I agree that about the hardest part of using a VFD is figuring out where to put it. For mine, I wanted the saw to be plug-n-play with any standard 240v household outlet… so the VFD was mounted on the saw itself. In essence, it makes the machine behave exactly as if it were a single phase machine. Since mine was missing the motor cover like yours is, I built my own and incorporated the VFD as part of it (as can be seen here). The way it’s enclosed, there is little chance of dust or other debris getting into the VFD, and it uses convection air flow, combined with the internal fan, to provide plenty of air for cooling. I have used it for extended periods of time, and the VFD barely got warm.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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magaoitin

246 posts in 788 days


#7 posted 06-09-2017 06:05 PM

Brad, Thanks for the correction on the ground wiring (I wrote that while at work and didn’t have a photo of how I wired mine :).

I wish my instruction had come with a diagram like that. The instruction out of the box and what I could find on their website is a little…sparse.

-- Jeff ~ Tacoma Wa.

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SweetTea

248 posts in 499 days


#8 posted 06-11-2017 02:09 PM

Ok, got the Teco FM50-202 ordered. Now I need to figure out how to attach the wires. In this pic, there are 4 wires. This is what is coming out of the box in the back of the saw (The motor has some wires that go into this box inside the saw cabinet on the back side of the inside of the cabinet, I have no idea what the box is) then the box has these 4 wires coming out of it.

Let’s start with how I connect these wires to the FM50-202. We can figure out the switch after I get this part down.

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MrUnix

6012 posts in 2038 days


#9 posted 06-11-2017 07:44 PM

Ignore the box on the back… that is the starter (LVC = Low Voltage Control) and will no longer be needed. Rip it out and sell it for a few bucks if you want. The VFD takes it’s place.

Wiring is easy. Your 240v supply (from the wall outlet) goes to L1, L2 and Ground. Motor gets wired to T1, T2, T3 and ground. You can use the wire coming from the motor – just disconnect it from the LVC and wire it to the VFD. If the motor runs backwards once connected, just swap any two of T1, T2 or T3.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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SweetTea

248 posts in 499 days


#10 posted 06-12-2017 11:07 AM



Ignore the box on the back… that is the starter (LVC = Low Voltage Control) and will no longer be needed. Rip it out and sell it for a few bucks if you want. The VFD takes it s place.

Wiring is easy. Your 240v supply (from the wall outlet) goes to L1, L2 and Ground. Motor gets wired to T1, T2, T3 and ground. You can use the wire coming from the motor – just disconnect it from the LVC and wire it to the VFD. If the motor runs backwards once connected, just swap any two of T1, T2 or T3.

Cheers,
Brad

- MrUnix

Let me see if I have this correct. The (red) hot wire from the breaker box goes to the L1, then the (black) wire from the breaker box goes to the L2 with the ground connecting to the ground spot on the FM50?

Then I should cut or disconnect the wire from the motor to the LVC, and connect red, black and white wires coming from the motor to any one of the T1, T2, and T3? It doesn’t matter which of those 3 wires mate to the T1, T2 or T3? Then, if the motor runs backwards, just swap the T1, T2 and/or T3 wires?

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magaoitin

246 posts in 788 days


#11 posted 06-12-2017 11:29 PM

That sounds right SweetTea. Here is the photo of my TECO mounted to the wall. You can see the orange Romex 240v from my panel with (2) black HOT and the ground (left side of the TECO). The other 4 wires (Blue, Red, Black and white) go directly to the motor. The only thing this does not give you is the use of the ON/OFF switch on the saw.

If you don’t wire in the ON/OFF switch from your saw, then you turn the saw on and off using the TECO

-- Jeff ~ Tacoma Wa.

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MrUnix

6012 posts in 2038 days


#12 posted 06-13-2017 12:23 AM

Yup… here it is a diagram that may make it easier:

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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SweetTea

248 posts in 499 days


#13 posted 06-13-2017 08:59 AM

Thank you so much, Jeff! Sounds like I should be well on my way to getting this bad boy wired up. Now I have to contemplate whether or not I want to pull the guts out and rebuild the saw. I am leaning towards yes on that. If I do, I will have the cabinet sandblasted and powder coated both inside and out. Replace the pulleys and belts. Replace the bearings, clean and paint (or powder coat) the internal parts. Decisions decisions!

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SweetTea

248 posts in 499 days


#14 posted 06-13-2017 09:02 AM



Yup… here it is a diagram that may make it easier:

Cheers,
Brad

- MrUnix

Thank you as well Brad! That really helped me understand the wiring situation!

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