3 Phase power convertering

[Barry Johnson]

Puchased a 7.5 3 phase sliding table saw and presently working on getting a phase converter for single to 3 phase. Anyone out here with experience as to pitfalls to watch out for. I have a 100 amp, 110 volt service coming into my place. I will be running the shop and house on this service. The saw comes with a 7.5 hp motor for the main and a 1 hp for the scoring blade

[John Renzetti]

hi Barry, I have three phase via phase converters in my shop. One of the phase converters is a Kay Phasemaster MA1B. This is rated to start a 7.5hp 3hp motor and run 20hp total. With this setup I have run a saw(7.5hp), scoring unit, (1hp) and the dust collector(5.5hp) with no problem. I have this converter fed by a dedicated 50amp 240v circuit. This circuit goes into a time delay fused quick disconnect. I've attached some pictures also.
Not sure of your other electrial power demands but 100amp might be cutting it close to run the shop plus the house.
Hope this info helps,
take care,
John

[Chris Giles]

Barry,
I have a Kay Industries 10 HP rotary converter and it does a fine job on my machines. Make sure whatever you get will accomodate your largest hp machine (usually a wide belt sander). It does require a 220 hookup, but is relatively simple to wire. You turn it on and off at a dedicated fuse box, and can leave it running for a few minutes or the whole day depending on your needs. I shut mine off after each use because it makes an unpleasant whining noise when running. The downside to rotary converters is the cost. Mine was about $1000 fifteen years ago, but is still purring along like new.

[Jim Becker]

I have a 100 amp, 110 volt service coming into my place.

If you truly only have 120v service, I believe there is going to be a problem accommodating your needs. (I would thing, however, that it would be unusual to not have 240v supply from your power company) Please clarify.

[Mark Singer]

I have the Kay M1a-R which is the same as John's except the disconnect is an attached box from the manufacturer... It seems to work fine....but noisey and it takes a 50amp 220v circuit

[Alan DuBoff]

Barry,

You should be able to convert your 100 amp 120v service into a 50 amp 240v service by using 2 breakers. However, 50 amps will most likely be marginal for the amount of HP you want to pull through it.

There are a lot of factors and I have a 7.5HP RPC running on a 30amp 240v circuit, which is not reccomended by most folks, but the RPC panel which came from Anderson Converters is marked for 30 amps, and the 7.5 HP idler is only 19 amps, which is low for a 7.5 HP motor, most are 23 amps.

It's confusing at best to sort through some of the info, and most folks will tell you that you need an idler that is 50% larger than your largest machine to start on it, so if you have a 10 HP machine, in theory that would be a 15 HP idler and panel to match.

With that said, I've seen where a table saw can operate on the same HP idler, and John's message supports that, just that most folks do not reccomend that. Again, I've never been able to figure out what requires 50% more or not.

I have a 5HP table saw that runs on the 7.5HP RPC fine. I also have another static converter that is a 3HP-5HP static phase converter, and I have a 5HP motor, so was thinking to wire it up and see if it would start my table saw.

The static phase converter I have is a phase-a-matic, and they say it can be used for an RPC by adding the idler motor. Anderson, OTOH, adds some extra stuff to his RPC panels, exactly what I'm not sure as it's rivited shut and I have not bothered in drilling them out to see what's inside. He states that putting a typical static phase converter onto an RPC will leave you with a less than full RPC. My guess is that he has some type of voltage regulator so that the voltage on the RPC stays constant. While probably not needed, it certainly couldn't hurt, IMO, and I feel more comfortable in having the RPC specific panel. I bought my RPC used from a guy in my area BTW, in like-new condition. My idler motor is setup for using on a converter specific, and the arbor was cut off of it.

If you don't have a panel and/or idler yet, check Anderson, his prices are good, or consider buying the entire RPC from a vendor, I think that's safer for some folks. Anderson does sell entire RPCs. You'll find that RPCs are not cheap, so it really only starts making sense if someone plans to convert their shop over or has multiple machines.

I also have a disconnect on my RPC. It goes from the panel to the disconnect with slo-blo fuses (needed for machines as they surge at startup), going into the RPC, and an outlet from the RPC which I plug my machines into. I only have 1 plug at the moment, but a friend is going to help me wire up more so I can run more than one machine. In theory I can run up to 15 HP on the same RPC (3x the amount of the largest motor, in this case I'm figuring 5HP although I might be able to start a 7.5HP machine on it).

Hope that helps rather than confuses you more...

I can take pictures of mine if you like, but busy today with a swim meet for my daughter.

[Jim Becker]

You should be able to convert your 100 amp 120v service into a 50 amp 240v service by using 2 breakers.

Not true unless he has both legs entering in his service. Two breakers on the same leg still result in 120v...not to mention something "not kosher". That was the gist of my previous question. If he only has 120v service (one leg from the pole)...not a good thing for this particular need.

[Charles Grosjean]

Puchased a 7.5 3 phase sliding table saw and presently working on getting a phase converter for single to 3 phase. Anyone out here with experience as to pitfalls to watch out for. I have a 100 amp, 110 volt service coming into my place.

Barry, assuming you ended up purchasing an Altendorf or MiniMax, there are a variety of rotaries to choose from. Kay through a combination of quality, service, and marketing seems to own a large chunk of the woodworking market and they are extremely helpful. Phase-a-matic also seems to be popular with various dealers (including the local to me Altendorf dealer). A newcomer with good reviews on Woodweb is American Rotary/Gentec with low pricing and nice features included, but I have no first or second hand experience.

Since you have a small service, you might also want to check into the power factor of the converter you are buying given the demands. As the power factor gets worse, you will end up with a larger current draw in your feeder to the converter (bigger breaker and wiring) and at some point, your total peak current from your service will be larger, ie you will be sucking more current (not power) into the shop than you thought.

If you won the lottery recently, take a look at Phase Perfect. 0.99 power factor and 1% voltage balance. Better overall performance than a rotary, but uses them newfangled transistor thingies. If you bought a tool with electronic soft start, then definitely consider the PP.

[Alan DuBoff]

Not true unless he has both legs entering in his service. Two breakers on the same leg still result in 120v...not to mention something "not kosher". That was the gist of my previous question. If he only has 120v service (one leg from the pole)...not a good thing for this particular need.

Jim,

I will admit to not being an electrical guru, and had a 220v circuit which I did use. I've been told it can be done, but again, not a guru on this. I procrastonated until I got a friend who is a guru with electronics to help me, so I didn't make any mistakes.

I will add this...(food for thought). Make sure you have your circuits wired properly, there are many homes that burn down because of bad electrical. I disconnected wiring and a power strip in my garage/shop that the previous owner had put in, because I didn't think it looked kosher, I didn't want to chance it. Using a disconnect is extra pre-caution, which I also reccomend on top of the breakers.

Most all electrical requires a permit to be done legally, and the reason is that many folks have made mistakes over the years and caused fires in their homes. I'm not saying don't do the wiring, or to hire a contractor that will charge you up the wazoo, or not pull required permits, etc...the choice is all up to each person to make for themself.

I don't get the permit thing, in the sense that I bought my house with non-permitted wiring in the garage, it was unquestionable that it was poorly done. The inspectors didn't say a thing about it when I bought the home. The city/permit system doesn't work well in it's entirety, IMO. I would rather have proper wiring and know it's done proper (even with no permit), rather than have bad wiring and have it permitted.

Another friend of mine hired an electrical contractor and in the contract it said they would pull all required permits. He check after it was completed and found out there were no permits pulled. The city told him there was not much they could do, other than telling him that they could make him pull it out if they inspected it in the future and there was no permit. caveat emptor I 'spose...<sigh> If you hre someone, don't take their word, require they show you all permits and paper work that is needed.

[Tyler Howell]

[quote=Alan DuBoff]Jim,


Most all electrical requires a permit to be done legally, and the reason is that many folks have made mistakes over the years and caused fires in their homes. I'm not saying don't do the wiring, or to hire a contractor that will charge you up the wazoo, or not pull required permits, etc...the choice is all up to each person to make for themself.

Permits are for your protection ( with the exception of some cities where they support the unions too ). Behind every rule or reg. is a fire, injury, lawsuit and or death. There is a fire in the U.S.A every 60 seconds and 95% of those are house fires. 98% electrical. (2004 stats).
I am the biggest advocate of DIY but you must not cut corners or make mistakes when it comes to wiring. They are deadly
My 5 hp PM 66 requires a 40 amp ckt. with #8 wire for my set up. I can make it work with speaker wire , but I am putting the saw, my home and family at risk with that kind of behavior. Because you can buy it at the borg doesn't mean it is legal in your home.
Some of my home projects (plumbing) I've had to redo a couple times but I learned from each experience. Better than starting from (a burn out) scratch.
I just replaced the main panel in my home. As part of my work I have a bag full of inspection tags but I pulled a permit and called out the local inspector so there would be no questions.
Some insurance companies are refusing to pay out if parts of the home do not meet code even if that infraction isn't related to that disaster.
CYA.
Some of the inspectors are real easy to work with and very helpful in getting the job done right.
In the time it took me to write this some ones home caught on fire and some one was hurt.

[Alan DuBoff]

Tyler has some good advice, would be good to heed it.

Just posted some info that I remembered (in another thread), and thought it would be good to post here.

When using an RPC, it is reccomend for the single to three phase conversion, you have 1.6x the number of amps. So, for an RPC with a 71/2HP idler that uses 23 amps, you would need roughly a 37 amp circuit of single phase, or tranlated to a 40 amp circuit.

This seems arbitrary, but a number that most folks use this 1.6x number. I say arbitrary since I have an RPC that uses a 7 1/2HP idler, but the motor only draws 19 amps, and 1.6x translates to 30.4 amps, so it makes sense that it can be rated for 30 amps (which the manufacturer reccomends). Not all 7 1/2 HP motors are so generous to require 19 amps though, most all of them require 23 amps, and in most cases that SHOULD have a 40 amps circuit.

As noted in John Renzetti's post, he runs a 7 1/2HP table saw on an RPC with a 7 1/2HP idler, and most people will tell you to use an RPC that is 1.5x the HP of the largest motor being used on the circuit. This would say to use a 12 HP (aprox, since it is really 11 1/4HP and try finding an 11 1/4HP motor, you'll need to get a 12HP) idler motor for a 7 1/2 HP table saw. I have seen some conflicting info, and have seen some sites say that a table saw is not a big draw item, unlike a band saw, which requires a lot more for startup to get going. In short, most folks I've asked about doing what John is doing have frowned on such an idea, but there are folks that claim they do it all the time. All our milage varies, and it's wise to heed Tyler's numbers on fires and such. IMO, it's better to be safe than sorry, but folks have told me that for a 7 1/2HP idler I should have a 40 amp circuit. I feel the numbers work out, and my friend that helped me wire my garage felt the same in looking at Anderson's requirements on the panel, along with the total amps of the 7 1/2 HP idler on the RPC.

FWIW, I have heard that the majority of fires in residential homes are from cumbustion fires, but I don't have any source for that information other than the Fire Chief from the local fire department when my wife caused an oil fire in the kitchen. Maybe that is issolated to our area on the west coast.

[Barry Johnson]

My apologies, I ahve 100 amp 220 volt service.
appreciate all the responeses so far. thanks

[Barry Johnson]

Went with the Phase Perfect - got sold on balanced line voltages. Also seems simplier install.

[Barry Johnson]

" take a look at Phase Perfect. 0.99 power factor and 1% voltage balance. Better overall performance than a rotary, but uses them newfangled transistor thingies. If you bought a tool with electronic soft start, then definitely consider the PP.

"

Thanks for all the good input from the creekers. Went to the "Manufacturing Forum" which was very helpful is getting a better understanding of 3 phase. In the end, I went for the Phase Perfect DP20 and it arrived a couple of weeks ago. VERY, very simple to install. The new Altendorf WA-80 seems to like it as well. Basically pulled wires from main panel to PP and then to switch and then to 3 phase panel and then to machines. I got the DP20 as I plan to replace other machines with 3 phase in the future. Again no worries about balancing lines and distance from the rpc. I found this on one of the forums and really like it ""Buy quality and only cry once."
barry

[Seth Poorman]

Ive been thinking on buying a rotary Phase converter is there any place to get them at a good price ? $1000.00 is alot of money, I could buy a couple new single phase motors for that !!!