Re-Wiring Delta Contractor’s Saw To 220V
loumickie | Posted in Power Tools and Machinery on
Hello Everyone,
I recently purchase a Delta 10″ Contractors Saw. I’m running a 220V circuit for my dust collector, so I planned to convert the saw to 220V also.
Unfortunately the manual does not include a wiring diagram or instruction for re-wiring. This particular saw has a pigtail from the motor that can be disconnected so the motor can easliy be removed.
If I remember correctly I’ll have to re-wire the switch and the connection at the motor. If anyone has converted their Delta Contractor’s Saw to 220 I would appreciate a quick go-by.
Thanks a whole lot,
Lou
Replies
I dont know how old your saw is but mine is about 3 years old and it has a diagram on the motor itself. Ya might try looking there. BTW been thinking about doing the same thing. Please let me know what ya think is it worth the hassel to run the 220 or not.
Darkworksite4: When the job is to small for everyone else, Its just about right for me"
Ron:
I hope I'm not intruding by throwing input into a question you ask someone else. I'm new to cyberworld. I started woodworking and tinkering with w/w machinery in 1972 and I might shed some light on your question.
Have you already got 220v wiring? Are you production or a woodworker that has another job to pay the bills like me. Ha.. Answer those questions to yourself and then consider the pros and cons of 220v.
If you don't already have 220v you'll have to wire from the box, obviously. If you are production or spend a lot of time running your saw it's worth it in my opinion (and everbodies got one). Here's why. 220v will increase the efficiency of your motor. It will run cooler and with less effort. It actually increases HP. Only a slight increase but enough sometimes to get you out when your over your head. Kind of like a fighter pilot kicking in a afterburner. This relates to motor life being extended. Also, you use for less electricity if power bill is an issue as it usually is in production. If you ever upgrade to 3 or 5 HP you'll have to switch anyway.
You are the only one that can answer if it's worth it!!!
Have a good one! Sarge..
Thanks sarge yea I have a sub panel ran out to the shop (my garage) with 220. I ran about 3 20 amp 110 circuits so far. Its just a matter of running the circuit. Like I said ive been playing with the idea. Im not a production shop but the amount of time I spend out there ya would never know (just ask the wife) . As for power well ya know we guys never have enough always need more. I think when i finally finish this Hickory kitchen. Ill do it, convert to 220 both the TS and DC. Thanks Darkworksite4: When the job is to small for everyone else, Its just about right for me"
Sarge,
I disagree with your assertion that running a saw at 220v vs 110v increases horsepower, makes the saw more efficient, or makes any difference whatsoever to the saw. There's another similar discussion on the Forum - can't remember which at the moment. I'd be glad to change my mind if you could please explain why the saw runs better or if you have some test showing higher power at 220v vs 110v.
There are 2 windings in the saw. At 110v, they are in parallel. When the saw is wired for 220 they are in series. The voltage drop across each winding is the same at both voltages. The current in each winding is the same and the power developed in each, therefore also in the motor is the same.
There is one, and only one advantage to wiring electrical equipment for a higher voltage (when such voltage is available):
. . . The run of wiring from the supply to the location of the equipment can be accomplished with lower gauge wiring. Since, at twice the voltage, the current is one-half, the wire cross section can be less. The reason is that the smaller wire, with its higher resistance will result in the same voltage drop as the larger wire carrying lower voltage/higher current. It's simply an inverse relationship.
The consequence of smaller guage wiring run? - lower cost. Period.
In factories where there is a great deal of wiring, often running for great distances, for many pieces of equipment, the difference in cost of the wiring becomes significant. In homes, this difference is often negligable. There isn't enough wiring run.
The power consumed by the equipment is the same, as long as the wiring is adequate for the equipment at each given voltage.
If you have another explanation, I'd like to hear it.
Rich
The same motor will start much faster on 200 than 110. That is the only difference I have noticed when switching from one to the other and I feel it is worth doing. As far as all the other assertions I have heard them all but have never seen anything to actually back up the theories.
Tom,
How much faster?
Again, there is no physical/electrical reason for such a difference, unless the capicitor start circuitry is not accomidating the voltage change.
Rich
Rich:
My explantion is I have simply been mis-informed by an article I read about 20 years ago! I've read similar a couple of times during that period. If you read my post to Loumikie you noticed that I mentioned I could run the lines but knew nothing of the internal circuitry. I've have been incorrect for about 20 years now and have mis-informed probaly 6 people during that time. Fortunately they are all in local club and I can correct them.
In Vietnam I specialized in setting uo ambushes with the 75th Ranger Reg. I obviously have started a major firefight here. Definitely not my intention! I apoligize to all as the error I made has led to obvious hostilities. Could there not be a more civil approach to get the correct information so we non-electrical people can make common-sense decisions about how we want to wire our shop! I'm totally confused at this point and would like to know the correct answer..
Hey, the truth is out there somewhere..
The not always right but not afraid to admit it : Sarge.
How about two explanations? First, there is a difference between the electrical power consumed in the motor and the mechanical power produced. The difference (numerically) is the heat released as current passes through the wire in the motor windings. Wired for a 240 supply line, this "Joule heating" loss is usually just a little less, and so Sarge is right to say the saw will be more efficient, although not by much, in normal operation. If the saw if bogged down, then the motor slows and current draw increases due to a reduction in "back EMF"; the result is that the heat loss increases proportionately more in the 120 v set up, and then it could make a difference worth noting, and perhaps even affect the motor's lifetime. Second, and this is what really matters, this a Delta Contractor's. Some models come with a motor that does not halve the current when wired for 240 supplies, and are rated at 2.0 hp with 240, although only 1.5 with 120. Delta does not make a big deal about this on their web site, but it is mentioned briefly in the blurbs for a couple of the versions.
42, the motor is not wired for 240, it is wired for two 120v series circuits instead of a single 120v parallel circuit. I think Delta is pulling a Craftsmen trick on you. It is physically impossible for the motor to create more horsepower unless it is physically altered somehow during the conversion. I may be wrong but I don't think they do that.Steve - in Northern California
Steve,
They usually don't, but actually can do that. It's not a simple series vs. parallel. There's a section of the winding that is not used when wired for 120v. Now, if I could just remember why they would do it......but the memory's faded too far...
Ahhh....it's the current! Say they want to be running on 220v at 10 amps to get good power. They also want to allow people to run with 120v, but typically need to limit that to 15-18 amps to run on a 20 amp breaker.
Gerry
Steve, according to Delta, the Marathon 1.5/2.0 hp motor is basically a 2.0 HP motor @ 8 amps. They then limit the amps to 13 amps when wired for 120 volts and that reduces the horsepower generated to 1.5 hp. The whole idea is to not get close to, or exceed 16 amps which is the normal limit in 12 gauge home wiring with a 20 amp breaker. Unlike Jet, Delta has a UL listing on their saw and therefore does not want to exceed the 16 amps.
Think of that motor as a "de-tuned" 2.0 hp motor when running on 120 volts.
Your summary on the Delta 1.5/2.0 hp motor should be the last word on this topic. Very well put.
42,
Very interesting comment on the Delta wiring. I haven't heard of anybody doing that for a number of years now, and didn't think about that. Sorta makes me wonder if there's more of those out there that we've missed noticing. Thanks for posting it.
Gerry
Sorry Sarge but my electric motor shop and a recent article in Junes Woodshop News by an electrical engineer says the opposite. In fact if you only have 208 you are killing the motor faster (actually runs hotter), spending more on electricity etc. Good article that is pretty informative and there was a recent post to the same effect and I believe that same electrical engineer, Rick Christopherson made a few contributions. Electrical questions are better suited to a known licensed professional in my opinion. If you drop your table saw on your foot are you gonna ask what to do about it here or see your doctor?
Why would you only have 208 at the motor???? Normal house current is 120/240. Just for fun I checked mine at the saw with recently calbrated fluke and had 244VAC. Where would the 208 figure come from.
Tom,
Some locations are supplied with 208v, not 220v. 208v is for lighting purposes. Undervoltage CAN burn out a motor because the windings then draw more current.
Rich
rsl:
Just wanted to say thanks for correcting me. I unfortunately have mis-informed several on this subject. I will check out the article you mentioned. I read this about 20 years ago and twice since seen it mentioned in wood mags. Obviously it was totally wrong or I have butchered the interpretation. I'll take your advice on qualified electronics person giving electrical advice. Thanks for your approach in correcting me. I have never been corrected by anyone I've ever mentioned this too; causing me to believe I'm may not be alone in what I thought to be general knowledge.
Keep up the good reprimands! I had my own company for 14 years and considered yours a classic!!
Have a good day! Sarge..
it's worth it! The motor will last longer et takes less juice in the end.
If you haven't already figured the wiring out your manual should have the ph# for Delta Tech. If not you can reach them at 800-438-2486 and they will transfer you. I imagine they can help you or send wiring diagram. A freind rolled mine over while I walked upstairs and got a cup of coffee. He mentioned 2 or 3 wires switched. I can run the 220v from the box; but not familar with internal circuitry so that's all the help I can provide.
Good luck..Sarge.
That makes sense. In that case you would be dealing with a commercial/industrial situation and should be running three phase equipment. Three phase motors a usually cheaper anyway. I don't think that really applies to the discussion at hand and only confuses the issue.
In regards to the startup speed issue the difference is considerable. (at least on the machines that I have run both ways)
3 phase has nothing to do with it. 3 phase is inherent in the generation of alternating current.
Rich
To clarify - alternating current as distibuted in most commercial power grids is supplied as 3 phase. Any one of those phases, or all 3 can be tapped for use. A motor that can use all three has three windings.
Both 208v and 220v are supplied 3 phase.
A motor that starts faster wired at 220v vs wired at 110v has been otherwise optimized for the higher voltage by circuitry apart from the motor itself. The power developed by the motor is the same.
Rich
Edited 7/28/2002 3:49:42 PM ET by Rich Rose
The issue of three phase power really has nothing to do with the subject at hand. I doubt seriously if the original poster has 3 phse power available at his house or any jobste he plans to work at so it just confuses the issue. It appears that the woodshop new issue was addressing running a motor designed for 220 single phase on 208. That is clearly a bad idea but has nothing to do with running a single phase motor on 110 or 220.
I don't know what circuitry seperate from the motor you are talking about. I have run my bandsaw and a contractors saw on both 110 and 220 changing only the connections at the motor itself and the difference in start time was considerable in both cases. Neither machine had any circuitry outside of the motor, just a switch.
Tom,
The motors have capacitors to absorb the start-up current surge.
Rich
"Tom,
The motors have capacitors to absorb the start-up current surge.
Rich"
Rich, I dont want to offend you but that simply isn't true. Capacitors are used in single phase motors not to absorb current but to start the motor. They do this by effectively shifting the phase angle. Three phase motors do not have any capacitors but don't seem to have a need to have their start up current absorbed by anything.
Tom
Edited 7/28/2002 8:59:34 PM ET by Tom
Tom,
No offense. I don't know why offering information here when it contradicts is often taken as offense . . .
Any way, I don't dispute the point. You are right. I was oversimplifying.
Rich
Steve,
"A motor capable of running on dual voltages is running in parallel when wired for 120V and series when wired for 240V. The voltage and current requirements are the same therefore the HP is also the same. You simply supply a separate 120 volt leg to each field winding in 240V. This can make the motor reach maximum rpm sooner since it take less time for the current to rise to required amount. The motor may also run cooler since the current would in theory be able to request and recieve the current faster when being placed under load conditions. The shorter rise time to current would mean that heat might be produced for shorter periods."
Sorry, none of that makes any sense.
The parellel and series part is correct. In parallel at 120v, each winding is seeing the same 120v applied at their comon connections.
In series, 220v is applied to the end of one winding. The other end of that winding is connected to winding no. 2, then the end of no. 2 returns to the mains. The voltage drop in the total windings resistance results in 120 v across each winding (measuring from the beginning of coil 1 to its common connection with coil 2, then measuring from that common connection to the end of coil 2.
In either case, the same voltage and current is associated with each winding. There is no such thing as the motor asking for current or shorter rise time for current or any other such assumptions about heat build up.
Rich
Hi.
I'm not an electrical engineer...or a licensed electrician, but I recently rewired my 110 Jet 1.5 HP contractors saw and 6" jointer from 110 to 220.
For the jointer, I saw NO difference, for the saw...all the difference in the world! I haven't tripped a breaker since rewiring...used to all the time on 110. My saw starts up much faster, seems not to bind or burn nearly as much.....for the 10 minutes that it took me..(and by the way, I only had to change the motor wiring...the switch stayed the same)....it was SO worth it!
Good luck!
lp
Ya got bad wiring, Larry. 220 is the way to go when the wiring's marginal.
Rich
Wow,
I must say as the original poster that the response was not what I expected, but very interesting nonetheless. I just went down to the shop and pulled the cover off the motor. In order to convert it to 220V I just moved one connection, simple. Now I'll just change the plug to make sure no one tries to plug it into a 110V outlet.
I am not running a commercial shop or three phase power. My Oneida DC requires 17A when running and up to 19A at start-up on 110V. The Delta TS requires almost 13A when running at 110V. Either way I needed two seperate 110V lines into the shop and a 20A circuit would just be adequete for the DC. It was easier for me just to run one 220V and run both machines off the same circuit with a 30A breaker. Now I can use the existing 110V outlets for other tools, and just in case someone else in the family decides to work with me in the shop we can run more than two things at once. Running a dedicated 220 circuit for the DC and TB wasn't that difficult or expensive, less than $75 bucks I guess. I have room in the breaker box so why not use it. I'm a bit of a perfectionist and for me half the fun is researching and building the shop.
Thanks for all the interesting discussion...
Lou
Be advised that table 210-24 of the NEC requires the use of 30A receptacles on a 30A branch circuit, which will also require 30A plugs. These (NEMA 6-30R/P or L6-30R/P) are physically larger than the 15 and 20A stuff, and more expensive. I'm not sure anymore if more than one receptacle is allowed on a 30A branch circuit for simultaneous use. If it were me, and especially since you have a sub-panel in the garage already, and since you're a perfectionist, I'd use a dedicated circuit for the DC (120 or 240V), and another circuit (240V) for all other large tools, with multiple outlets, assuming you never run (or at least start simultaneously) more than one large machine at a time. If in doubt, call an electrician, or your local authority. Reading this thread should convince you not to take electrical advice, including mine, from the internet.
Be seeing you...
Steve,
Thanks for your concern, but I'm not feeling bad at all. And in case you are getting confused, we have not been talking at all about "electron theory stuff," although if you would like to have a discussion about electron theory, particle physics or just mundane electronics, I can certainly accommodate you. But, we have been talking about plain and simple electricity here and electrical wiring setups, basic Ohm's law.
I really can't tell if you are being arrogant or just making a poor stab at humor. But you're giving some misinformation here, invoking non-existing physical principles and then using phrases such as "nobody really understands this stuff anyway." I just get the feeling that you are throwing out catch phrases that you don't understand.
A typical AC motor which has the capability of 110 or 220 operation has two coils. When wired for 220, yes those coils really are in series across the 220 winding of the external power company's power transformer. There is a "ground" connection which is the center tap of that transformer and which is common with the "center" connection of the two coils. That doesn't change the topology of the circuit in any way.
But there is no "separate series circuit" for each coil as you say.
Steve, and Rich,
Boy, does this subject seem to repeat itself. In any case, this theory stuff has been "proven" many times. If you take an accurate set of measurements, you can predict the results very well. Now, it was a bit difficult to see where Steve and Rich disagreed, since you're both essentially correct. The only area that's questionable is:
"A motor capable of running on dual voltages is running in parallel when wired for 120V and series when wired for 240V. The voltage and current requirements are the same therefore the HP is also the same. You simply supply a separate 120 volt leg to each field winding in 240V. This can make the motor reach maximum rpm sooner since it take less time for the current to rise to required amount. The motor may also run cooler since the current would in theory be able to request and recieve the current faster when being placed under load conditions. The shorter rise time to current would mean that heat might be produced for shorter periods."
And only regarding the rise time, and even here Steve does have some justification. Two things will impact the rise time, one being the wiring inductance against the source impedance. In practice, this is so short that you'd need special equipment to measure it. We're talking about less than 0.2 seconds, and probably much less. So that part is true, but you wouldn't see it, and let's forget about that part. I only mentioned it because the term risetime usually relates to inductive delay.
The more significant item has to do with the voltage loss in the wire, against the initial startup current surge in the motor. For the same wire size, moving to 220v will half the current and half the voltage drop in the wire. In either case you will get some % voltage drop during startup. For the same wire size and length, this drop will be less for 220v. So what does this mean? If your wire is too small or long, switching to 220v will give you a noticeable improvement in the motor startup, and be able to better hold speed under load. But if this isn't the case, you probably won't be able to detect any more than a very slight difference.
In either case, the motor startup time is short enough compared to its runtime, that it won't run any hotter or cooler either way. Caveat: If you're 120v line only delivers maybe 95v to the motor, then it will run much hotter. A cheap voltmeter can tell you this (if you're interested). Finally, if the motor is running at 100% (or any other %) of its rated voltage, it doesn't matter if it's 120 or 240, as you'll have the same power and the same heat.
Finally, from here on I'm going to shut up about this. The two of you know enough to handle other questions, and after >30 years in electrical engineering, I'd rather go cut wood:-)
Gerry
Steve,
Thanks, but no thanks on the moderator job. Just read the post from 42, and he's saying essentially the same as I did about the difference, only using joules instead of volts and amps, so there are many ways of saying the same thing.
IMO, much of the confusion comes from people quoting posts or even mag articles as authority, instead of a textbook. It's also sometimes hard to tell which effect is important. For instance, there are actually 3 different reasons for including a capacitor with a motor. In one case it's a start up capacitor for a large motor, in another it's part of a phase shift network (a _very_ large motor), and the third (most common) is a small capacitor as a transient or spark supressor. When you have brushes and a commutator there are connections constantly made and broken. The motor wiring has inductance and, when you break a current bearing connection it causes a sharp voltage rise. The exact same principal used in firing the spark plugs in your car. Since we don't really want this happening to the brushes, a capacitor is used to absorb the very brief voltage spike.
Another fellow mentioned phase shift networks, but that's only practical on heavy equipment, and takes more than what you'll find on a typical shop motor. As for the startup capacitor, I recall seeing them with larger air conditioning systems, which may start under load.
But, here I go again...I'm responding to five posts at once. Time to call it a night.
Gerry
Just thought I would post some good info on what the capacitor does in single phase motors and why it is necesary. I found this to be a very good explanation of the difference between starting 3 phase and single phase motors. Got the info from http://www.capacitorindustries.com/Tutorials/Motor%20Starting%20Capacitors.htm
WHAT DOES A CAPACITOR DO IN A CAPACITOR START MOTOR TO MAKE IT START?
An electric motor is basically composed of windings around a magnet. Motors are either multi-phase or single-phase. Multi-phase motors generate starting torque along the various windings by applying out of phase voltages to each winding in a pattern that generates a torque force in the desired direction. Single-phase motors must generate the same starting torque however they have only one phase to work from. This means they have to have a method to generate a shifted version of the single phase voltage to send to one of their windings.
There are three common methods of creating single-phase electric motors: capacitor start, split-phase, and shaded pole. Each other these motors has some method to provide starting torque to the motor by shifting the voltage given to one of the windings on the motor by some angle. This phase shift corresponds to one winding of the motor having a voltage before another coil. The difference in time between when one coil has a voltage and when a second coil has a voltage causes the torque force and begins the movement of the motor.
To start to solve why capacitive start motors work we can generalize Ohm's Law, V = IR, and say that V = IZ where Z is a generalized impedance. The impedance is composed of an the inductance, capacitance, and resistance. Inductance will cause the current to lead the voltage, capacitance will cause the current to lag the voltage, and resistance has no effect on the timing between the current and voltage.
In all motors the windings of a motor are highly inductive so the voltage always arrives after the current. The capacitor changes the relative impedance of the circuit on one winding causing the shift in the relationship between the voltage and current on one winding and the voltage on current on another winding. This difference in the time the electrical energy is dispersed in a winding allows the motor to rotate.
In summary, the capacitor provides a delay in the energy given to one of the windings. This delay causes the forces of the motor to be unbalanced and the motor then starts. Economically, capacitor start motors are often more costly due to the inclusion of the capacitor however they have the most starting torque This means that you probably have one in your refrigerator, washer, dryer, or other application where you may need a lot of starting force but you won't find them in your electric fan.
Jason Viehland, Staff, Research and Development, Teradyne
Hope that helps some. I know it doesn't address the 120/240 issue but it should clear up alot of the other things that have been posted.
You all might be interested in this website.
http://www.howstuffworks.com/motor.htmSteve - in Northern California
I think that site only addressed dc motors for simplicitys sake. It does't begin to address the differences between single and three phase motors or the difference in 120 and 240 wiring.
Tom, if you surf the site, its all there. I just pointed to the electric motor principles section. They also cover electrical power from the point of generation to delivery to the home. They don't go into too much depth but its enough to get a good understanding of how it all comes together.
Once you read it and with the knowledge of capacitors that you've gained, think about what 240 is again and I think some of the answers to many of these questions will be answered.Steve - in Northern California
Steve, I don't have any problem understanding what the difference between 120,240 single or three phase power. I deal with all of them frequently as well as 400cycle ac and 60 cycle a/c. The problem in this thread is the people have introduced things into the thread that had nothing to do with the posters question and made for a lot of confusion. 208v power and three phase should never have really been brought into the picture.
I linked to the capacitor site because it has come up a few times in this thread with some very contradictory info. I thought the site gave a good concise description of what it actually does.
Edited 7/30/2002 9:06:09 AM ET by Tom
Tom, I couldn't agree more. Steve - in Northern California
Last time. There's no need beating this nag no more:
A motor with 120/240 capability - there is no difference in any practical parameter when running the motor in either of its configurations. It develops the same power, uses the same current and behaves to the woodworker as the same piece of equipment.
There are infinitesimal differences in operation that require test equipment to percieve. The differences caused by phase delays, inductive effects, etc are laboratory stuff. They make no impact on the actual operation of the motor.
If anyone is experiencing significantly improved performance in a dual voltage motor at 220v because at 110v, the current draw is dropping significant voltage in his/her house wiring, it's time to get that wiring replaced, or put in a proper fuse so that it blows under such a load. No way should any house wiring be that inadequate. If it is, it's way below code and is a fire hazard.
I've serviced and maintained air conditioner motors, heavy equipment motors, woodworking equipment, as well as designed and maintained elctronic speed controls, test equipment, digital and analog interfaces. The motors have ranged from 1/2 horse to 10 horse, single phase and 3 phase. I've put in my hours in this kind of thing. I'll stop trying to say the above any more. Wire a dual voltage motor either way, It's the same beasty.
Thanks for all the information, guys. Steve, I can't really put my finger on it, but post after post, you seem to say just enough to confuse this issue and get the point just wrong enough that it makes no sense. "Last time I checked, electricity flowed from negative to positive and since there is no return line (neutral) on this 240v circuit the common potential is ground." I sure wish I knew what that meant. Or do I? 'Nuff.
Rich
there's been lots of confusing info given. My knowledge says this. You sound like a home shop worker; assuming the US you will have 120/240. Drop a 12/3 wire for the length inside a shop and, no significant problems should exist. Fairly simple installation. The 208 discussions apply to foreign and commercial applications. Your power supplier would charge an arm&leg for three phase service anyway.
you need to know:
run a 12/3 in surface mount metal conduit from the panel to your outlets. you will get 120/240v due to residential/ light commercial service. Your motor needs rewiring; usually just swapping connections to the motor et should be noted on the motor. The switch may or may not need work depending on its internal working; poen it and look it's usually noticable.
I really hate to post in this forum again, the last time I had to agree with the electrical engineers (that ain't good for a journeyman electrician). Just kidding EE's.
If you increase the voltage of a piece of electrical equipment, you decrease the amperage by the same amount. 110V changed to 220V increases the voltage by two, so your amperage will decrease by half. Voltage and current are inversely proportional. If you look at the ratings on the motor, it will show you that.
Never assume that because you have enough blanks in your electrical panel, that you can safely add more circuits. You need to have a qualified person check the total amperage draw at the service entrance of the panel as to not overload the panel.
Ohm's Law is the theory.
Good Luck, Len (Len's Custom Woodworking)
Steve:
P Co. 75th Ranger Reg. 5th Inf Div. I Corp VN 68-69. Took shrapnel hit RPG day three-five-niner.
First, thanks for your service! Got message Lima-Charley.. Thanks for help clarification 120 versus 220.. Thanks to all by the way. If I am reading between lines correctly, it seems some of you guys that have been on this website a while seem to enjoy a good bar-room brawl and this subject has arisen b-4. I was so confused originally I went down to my shop and pulled the 220 wiring to my TS and replaced with hand crank.. I am a decent machinist with good mechanical apptitude but I am way over my head with electricity. I ran 2 20 amp lines down both sides of shop and a 220 to saw specifically because I was mis-lead years ago to believe this was more efficient..I had a Delta rep at International Woodworking Show here in Atlanta years ago lead me in this direction also.. (Theres a clue for you 42 and Gerry001) I also read all fine print on various companies specs sheets cause I am very interested in the mechanical workings.
Now, am I dis-advantaged by keeping TS 220v or from what I think I've gathered here it doesn't matter either way as I'm maintaining same HP and efficiency regardless and using the same amount of power! I hope I don't open up another can of worms. I woke up this morning wondering why my washing machine and frig is wired 220v.....forget that .......unfortunately I don't have time to go to the text-books for answer( excellent observation Gerry001 as most of us without ee knowledge rely on mags and info from manufacturer)..
Finally, I have learned mucho here even though it's way over my head! Thanks to everyone that contributed as it has certainly been interresting..
Sarge..Out.
Since you seem interested in how these dual-voltage motors work, here's the connection diagram from a Baldor single-phase, single-speed motor. Every such dual-voltage, single-phase, single-speed, capacitor-start, induction-run motor I've ever seen works the same way, from cheap AC blower motors to larger PSC air compressor motors. There are three windings, two main windings and one start winding. The start winding is always connected in parallel with one of the main windings, and that pair is then connected either in series (for 240V operation) or in parallel (for 120V operation) with the remaining main winding. It's the start winding leads that are reversed to change motor rotation, and it's only in the circuit until the motor exceeds some minimum speed as determined by the centrifugal switch. Now, if you think about it, there is a (minor) difference during starting only between the two configurations, because all three windings see line voltage across them when connected for 120V, but the main windings are not balanced due to the start winding being in parallel with one main winding during starts when connected for 240V. But there is no practical difference in real life. I've connected a neutral to the common point (2,3,8), just for sh*ts and giggles, and it stopped the motor from whining while starting, but didn't improve start time. I'm just pointing that out to keep the fun going.
nb: I don't know what the rules are for posting this diagram, but there is no copyright info on it, and Baldor makes it available for download on their site. If anyone knows a reason why I should not post it here, please let me know.
Be seeing you...
Sorry for the deleted graphic. Taunton won't let me post that for possible copyright infringement reasons, so here is a link to the link. You'll have to download Whip! Viewer (an AutoDesk web viewer, I think; it downloads and installs quickly), unless you have a CAD program that will read .dwg files. You want the Connection Drawings - View Online button (bottom left).
http://www.baldor.com/products/caddrawings.asp?1=1&catalog=L3606&product=AC+Motors&family=General+Purpose%7Cvw%5FACMotors%5FGeneralPurpose
Be seeing you...
Edited 7/29/2002 6:14:44 PM ET by TDKPE
TDKPE:
Thanks for the attemped download on Baldor. I went to site as I have been looking around for grinders anyway. You don't happen to have that Baldor diagram cause you have a Baldor slow speed grinder do you? You know if you do you might just UPS it to me for a couple of years so I can study the circuitry close up. Would help for me to have a close look! You probaly wouldn't mind if I used it to grind a few edges in preparation for honing while I study the circuitry I'm sure..
Seriously, thanks for the assist as this topic has been a crash course in internal wiring. It's generated an interest in a better understanding of what happens when the juice hits the power source.. Again, thanks for your help..
Have a good day.. Sarge.
The main reason large appliances in the house are run on 240 is the amount of current neede to run them. At 120 they would need twice the current and the wire size needed would be much greater. 240 solves that problem. That is why larger motors can be run only on 240. The current requirements for running them are simply too large for 120 too handle.
Tom:
Thanks for the confirmation. I actually thought I knew why they require a 220v and I was right. But, one thing I've learned here is it's not a bad idea to check it out with qualified people in a particular field just to be on the safe side. I really hated to post here as I think 42 in post to Howie 7178.41 in reply 7178.34 summed it up extremely well! But, where I come from when someone gives you a helping hand you return the courtesy by saying thanks for the help.
THANKS: Sarge.
This forum post is now archived. Commenting has been disabled