Restored Unisaw needs power!

[josh miller]

Hi everyone,

After several months of my off-time I've spent restoring this Delta/Rockwell Unisaw from a rust bucket, I need some help in the wiring. I ran across this site and you guys seem to be very knowledgable with this equipment. I would like to use my existing 220V from my dryer plug to run this 3 phase motor using the Phase-a-matic static phase converter that I purchased (manual w/schematics at http://www.phase-a-matic.com/PDF/SIS-2009.pdf). I'm no electrician but I studied up a bit and figured this was my only option if I wanted to keep the saw aside from replacing the motor entirely, which seems a bit blasphemous considering the torque it can generate. I posted some before and after pics of the table saw. I've put a lot of work into this so far.

There is an external unit of some sort (see the attached pictures) where the On/Off switch lines (black, white, green) come in at the top left and the motor lines feed in from the right (green, tan, black, red). I intended to keep this saw wired as it is pictured but using the phase converter outputs A, B, C to L1, L2, and L3 (see attached picture of the saw circuit schematic). I have no real idea how this should be wired and need help to complete my saw and realize the completion of my project! Any help would be HIGHLY appreciated. Thanks in advance!

[Dave Cav]

Your saw turned out very nice. I don't have enough details from the pictures to try to help you wire the starter, but if you go over and talk to the guy at owwm.com someone there is bound to know exactly what you need to do.

[Fred Hargis]

Agree with the trip over to OWWM. Those guys convert 3 phase daily. Be aware, the first piece of advice may be to toss the static phase converter...but someone there will know how to make what you have work.

[Ben Martin]

Where did you get the goose egg from? Appears that yours might be plastic, I need to get one for mine.

[Bob Aquino]

Josh
You have three ways to run that machine off standard 220V power. The first as you correctly surmised is to use some sort of static converter. They are simple devices with no moving parts that use capacitors to simulate the third leg of the 3 phases long enough to get the motor moving then they are supplying 2 phases to keep it running. Whats wrong with that? You are only getting 2/3 of the power out of your motor. Some motors can run ok on them, others cant.
The second method is to use what is known as a Rotary Phase Converter (RPC). It is similar to a static converter, but it uses an existing 3 phase motor that makes up the third leg. You get true 3 phase power but at the cost of having a 3 phase idler motor running the entire time you want that power. Most RPC's use something along the lines of a 5hp or better motor for the idler, so it does draw some current.
The last method and what seems to be the most popular choice is a Variable Frequency Drive or VFD. These are small, solid state devices that take 220V and convert it to true 3 phase power. They have some added advantages like being able to control the motor speed and electronic braking of the motor. Thanks to our friends in Asia, they are relatively cheap, some going as cheap as 100 bucks. The cost factor is directly related to the HP of the motor. 1 HP or less is very cheap. 2-3 HP goes up some, over 3 HP it gets very expensive. Factorymation.com is one online source, there are plenty of others. The advice to peruse the owwm.org forums is spot on, its a much discussed topic over there. This is a pic of the VFD that I used on my 3 phase Rockwell bandsaw that I restored last year so you get an idea of what I am talking about:

[Rod Sheridan]

Hi Josh, your restoration looks nice.

A couple of items i noticed is that the cab tire that goes to your push button station is using the green conductor as a current carrying conductor. The green should be ground only, so you need a piece of 4 conductor cab tire for the push button station.

The other item of course is the connection where the wire doesn't have a lug, you should crimp an appropriate lug on the wire.

Once you hook it up to a 3 phase source, you may find that the motor runs backwards, so try it out without the blade/washer/nut on the arbour first.

If the rotation is reversed, interchange any two motor leads at the starter to reverse the rotation.

Regqards, Rod.

[don romans]

Where did you get the goose egg from? Appears that yours might be plastic, I need to get one for mine.

Email this guy, I believe that he still makes them
peytonkale@yahoo.com

[Thomas Syrotchen]

Just a note on using VFD's for 3 Phase power. Unless the VFD is specifically designed to use single phase power, you will need to derate the drive 50% if you only provide single phase power to it. In other words, if you have a 3HP motor, you would need a 7.5HP drive. Not all VFD's are also capable of handling only single phase power inputs check the specs.
The static phase converter you posted will likely work just fine.
Your best option though may be to replace the motor with a single phase motor which may be the cheaper and more reliable way to go. Just a suggestion, I'd price out both options and if the cost is similiar I would replace the motor with a single phase one. From a reliability standpoint its a better way to go.

[Jerome Hanby]

I got mine from workforarn or something like that over at OWWM. It's fiberglass. Just checked my PayPal account, it was $124.80 delivered.

Believe his actual name is Tom Davis, email is tcd@tcdcpa.com. Best way to contact might be a PM on OWWM, that's how we conversed.

I got my egg in last week and it's great. Once I primer and paint it (also painting the Unisaw), I think it will look very authentic.

Where did you get the goose egg from? Appears that yours might be plastic, I need to get one for mine.

[Carroll Courtney]

I just purchase a drive and in the process of installing it on a PM90 1hp 3phase lathe.To my door it was 145.00 which means I can either make it exclusively for the wood lathe or I can fix it to where I can also run other machines using the same drive that have a 1hp motor.Static converter loss 2/3 of power you mine as well install a 1hp motor.But as other have stated,if your in to deep on the converter OWWM is a good resource and Practical Machinest is another info source.Please post pics of your work-----Carroll

[Bob Aquino]

Just a note on using VFD's for 3 Phase power. Unless the VFD is specifically designed to use single phase power, you will need to derate the drive 50% if you only provide single phase power to it. In other words, if you have a 3HP motor, you would need a 7.5HP drive. Not all VFD's are also capable of handling only single phase power inputs check the specs.
The static phase converter you posted will likely work just fine.
Your best option though may be to replace the motor with a single phase motor which may be the cheaper and more reliable way to go. Just a suggestion, I'd price out both options and if the cost is similiar I would replace the motor with a single phase one. From a reliability standpoint its a better way to go.

Uh, NO. One HP or less you may have a drive that will run off 110. Over 1 hp and its all 220. Over 5 hp and they start calling for 3 phase in. You don't want to fry the drive by trying to run it on only on single phase 110.

Replacing the motor is the most expensive option, go out and price a replacement bullet style motor. If you can find one, they are probably around 300 used and they go very quick. You can't substitute a more modern style Uni motor, it will hit the edge of the opening as you tilt the blade. Thats why they rounded the ends of the motor.

Seriously, the guys at OWWM are much more tuned in to this type of question. Good Luck.

[josh miller]

Thanks everyone for all the responses. Good information. I'm going to post at owwm as well. I really need to be sure to get it right!

Ben,
I got the motor cover from a local plastics manufacturer called Bell Plastics in Hayward, CA. The guy that molds them sells them on eBay for a decent price. Search for "Delta Unisaw motor cover" on eBay. The link below won't work for too long:

http://cgi.ebay.com/Rockwell-Delta-U...d=p3286.c0.m14

I found it necessary to trim the lip around it to fit with my power setup but it's a great fit.

Also, for anyone interested I discovered a great product for rust removal during my project. It's called evapo-rust and it is honestly the best thing EVER for rust removal. Water based, non-toxic, hardly any scent, soak it and forget it buckets of awesome. It won't pit your part either. Just look at the examples attached as to the before and after state after a one night soak and a light wire brushing... truly an amazing product. Like brand new worm gearing (and every other part on that saw) with minimum effort.

You can find it here if you need it for anything:
http://www.theruststore.com/Evapo-Rust-Gallon-P1C1.aspx

[Dave Cav]

Another vote for the VFD. I have a Teco 3HP FM50 on my Delta 12/14" table saw. I got it from Factorymation for $195, including shipping. One for your saw would be less, and will work a lot better than a static phase converter.

[Chip Lindley]

The OP is using a static phase converter, not a VFD! The restored Unisaw appears to be 3 hp! 2/3 of of 3hp will still be enough hp to rip 8/4 oak!

Hanging a VFD on every separate machine is quite a Pricy Proposition! Just spring for an RPC (rotary phase converter) and you can power all from the same source.

Is it just a wild rumor? or do VFDs running a machine at reduced speed, also reduce available torque? Hmm....

[Chip Lindley]

Static converter loss 2/3 of power you mine as well install a 1hp motor.....Carroll

Carroll, don't make it any worse than it actually IS! Static phase converters lose about 1/3 power to a motor. Under heavy use, the power may drop to Half! But nowhere do I find that a static phase converter lose 2/3 usable power for a 3-phase motor!