got my motor.....but..........

Frank Fusco

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Mountain Home, Arkansas
:dunno:
My friend picked up my new motor at Harbor Freight today.
Now, I don't know if I can use it. I specified a single phase 2 hp., 3450 rpm.
When he got there the only 3450 motor they had was a single phase 3 hp.
OK, so far, so good. Right? Not sure.:rolleyes:
Now, most of you know me and elektriks. Not good. :(
I always thought single phase meant 110/120 V. Apparently not. This motor is 240V.
It is also called a "compressor motor" on the owners manual. I dunno if that disqualifies it for a table saw. I do have 240V in the shop. It is run to my lathe with a simple plug in. I can make an extension cord from romex and some connectors (expensive) but will not have a switch. The foot switch I bought is only listed for 110V. I'll have to buy and rig up some kind of switch.
BTW, the motor is a Smith+Jones make and it comes from some exotic oriental country.
Price was only $159.99. A budget buster for me but not too bad. Will have to sit on this situation until Monday and thimk it over. :huh:
 
Is the motor the same frame style as far as being open where you can see inside? If so and the shaft size is the same and it will bolt in place then use it. You'll just have a little more power.
A compressor motor always draws full power unlike a table saw motor that only draws what it needs to make the cut.
 
Not sure but I think you need to consider the weight of the motor & the thickness of the casting & construction of the saw. It was only made to handle so much motor weight & still be able to elevate & tilt. It is possible to overtax the casting & crack it. With the construction & the way the motor is mounted & suspended to much weight will over stress the the whole system.
 
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...I always thought single phase meant 110/120 V. Apparently not. This motor is 240V...

Yeppers, as you've discovered, the single phase/3 phase denotation has nothing to do with the voltage. I won't try to explain the difference (you and elektriks, and all that), but suffice to say that most home shops are only using single phase power.

I'm with Bart, though. That saw may not be beefy enough to handle a 3 HP motor. Also, putting together a 240v switch will likely be kind of costly. Lastly, making an extension cord out of Romex is flirting with disaster. Not saying I've never done the same thing, but it's not a good idea. The wire inside is not meant to be bent repeatedly (as will happen with an extension cord). It's meant to be bent once as it's built into a wall, then left alone. You'll be running a risk of a broken wire, short, or fire.

Harbor Freight has a good return policy (which I believe also applies to their motors). My suggestion would be for the friend to take it back next time he goes there. ;)
 
I'm not sure about anything at this point. I was thinking about running a line (OK genuine extension cord) from the connection at my Griz lathe for the saw. I would need a switch. Costly. But, again I'm bumfuzzled with the single phase/3 phase thing. Here is what I have on the G0532 lathe from Griz' own specs: <<<•Motor: 1-1/2 HP, 220V, 3-phase with single-phase frequency drive
•Power requirement: 220V, single-phase>>>
How can it be three phase with single phase. Huhhhhhh???? :huh:
 
Frank i wish you were closer to Larrys place, would have no problem popping over and helping you sort this out. I also think you best be changing up that motor. I wont confuse you further with the explanation on your lathe.
 
I'm not sure about anything at this point. I was thinking about running a line (OK genuine extension cord) from the connection at my Griz lathe for the saw. I would need a switch. Costly. But, again I'm bumfuzzled with the single phase/3 phase thing. Here is what I have on the G0532 lathe from Griz' own specs: <<<•Motor: 1-1/2 HP, 220V, 3-phase with single-phase frequency drive
•Power requirement: 220V, single-phase>>>
How can it be three phase with single phase. Huhhhhhh???? :huh:

Single phase is anything that requires a single or a double breaker ( two single breakers connect together ).

On your lathe they are taking 220 volt single phase and converting it to 3 phase electronically.

Put your original motor and the new motor side by side. If they are very close to the same size and weight and you don't mind getting a different switch then use it.
 
Frank, the motor on your lathe is 3 phase. The frequency drive is single phase and allows the machine to operate off of single phase. Your new saw motor has two things for you to consider. One, it is 220V, single phase. Extensions cords and switches are quite pricey for this. Can't use any old extension cord and you also cannot extend too far. I have a 15 foot #10 wire extension on my 220V 3HP Grizzly saw, as an example. The plugs and outlets can easily run over $20 a pop. The cord is also quite pricey, likely well over a dollar a foot. The second issue is the weight of the motor. And that maybe your real kicker. I'd suggest to keep things simple and within the realm of the capabilities of that saw, exchange the motor for a 110V signal phase of lesser power and less weight. Just suggesting, or this could get weirderer and weiderer. And much more expensive.

Let's just say, you need 20' of cord. You have the motor cord plug, the two ends to the extension cord, and the outlet. Let's say the wire was $1.50 a foot and each plug/outlet was $20. My pencil says $115 to get the saw motor plugged in. Ouch! and I've BTDT! Hit up your electrical supplier and take your calculator. And remember, each of those items needs to be wired up. Not to mention you don't like electric stuff. :)
 
Frank, the motor on your lathe is 3 phase. The frequency drive is single phase and allows the machine to operate off of single phase. Your new saw motor has two things for you to consider. One, it is 220V, single phase. Extensions cords and switches are quite pricey for this. Can't use any old extension cord and you also cannot extend too far. I have a 15 foot #10 wire extension on my 220V 3HP Grizzly saw, as an example. The plugs and outlets can easily run over $20 a pop. The cord is also quite pricey, likely well over a dollar a foot. The second issue is the weight of the motor. And that maybe your real kicker. I'd suggest to keep things simple and within the realm of the capabilities of that saw, exchange the motor for a 110V signal phase of lesser power and less weight. Just suggesting, or this could get weirderer and weiderer. And much more expensive.

Let's just say, you need 20' of cord. You have the motor cord plug, the two ends to the extension cord, and the outlet. Let's say the wire was $1.50 a foot and each plug/outlet was $20. My pencil says $115 to get the saw motor plugged in. Ouch! and I've BTDT! Hit up your electrical supplier and take your calculator. And remember, each of those items needs to be wired up. Not to mention you don't like electric stuff. :)


I have a 3 Hp Unisaw & if I remember right it can draw as much as between 8-9 amps on each leg totaling 18 amps which is run on a 15' good quality 12 gauge cord not much use in putting a 10 gauge cord on a circuit that is wired in the wall with 12 gauge wire & run off a double 20 amp breaker. Cost me about $20 for the plug & cord. Most motors usually need to have the cord installed unless they are used & already have the cord installed. Frank it would really help you to find a simple book about electrical with lots of pictures & good explanations.
 
...How can it be three phase with single phase. Huhhhhhh???? ...

Frank, the little plastic box on the back of your lathe's headstock is the "frequency drive". It is also sometimes called a phase converter. As Carol mentioned, that little box takes the single phase electricity coming from your wall and converts it into the 3 phase electricity your lathe's motor needs. In the process of doing this, the little box also adds the capability of slowing down the motor...in other words, the electronic variable speed.
 
Anything over an honest 1 1/2 hp draws more current than is available in a household circuit, so UL won't approve it with a regular 120 volt plug. When you switch to 240 volts, not only is the motor happier but the current drops in half, so a 3 hp motor that might have needed 30 amps at 120 volts only needs 15 amps at 240 volts, and works with #12 (or arguably #14) wire.

All the wire I have seen will handle 240 volts. Therefore you can buy heavy duty wire by the foot at $1-2 per foot, or you can buy a 50 foot extension cord with #12 wire for around $25, and have a supply of very flexible brightly colored power cords for your machines. Change the plugs to the 240 volt plugs to be legal, and you are set. You can buy 20 amp 240 volt plugs for a modest price (under $5) - one of the blades is sideways so you can't accidentally plug it into a 120 volt outlet, or vice versa. Those cheap plugs are often used for big window air conditioners. I like the locking plugs used on industrial machinery: L6-20P is the NEMA identifier for the 20 amp 240 volt locking plug, L6-20R for the receptacle, but these cost about $20 each.

By code you need a disconnect outside the machine. A 240 volt wall mount switch is expensive, but a plug counts as a disconnect, so put in a plug and outlet, and you meet the disconnect rule (so you can safely work on your machine wiring).

240 volts normally switch both sides, not just one side. Therefore you need a double pole switch. Sounds expensive, but Home Depot and Radio Shack have such Switches that mount on a metal box for under $5
 
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FWIW, I was going by my 30 amp circuit for my saw. #10 wire and twist lock plugs and DPDT 240V switch (for the lathe) I have both on one circuit. The saw manual recommended a 30 amp circuit. The lathe a 20 amp circuit. So I wound up spending boo-koo bucks! :eek:
 
FWIW, I was going by my 30 amp circuit for my saw. #10 wire and twist lock plugs and DPDT 240V switch (for the lathe) I have both on one circuit. The saw manual recommended a 30 amp circuit. The lathe a 20 amp circuit. So I wound up spending boo-koo bucks! :eek:

Sorry Carol I didn't mean to step on your toes. I actually had both my 3 HP Unisaw & my 1 HP Jointer on the same breaker & many times ran them at the same time. If the manufacturer recommends 30 amps then that's what you gotta do.
 
Ok here comes one of my "ask me the time, and I will tell you how to build a clock factory" answers.

The starting current for most items is many times the peak current. My 5 hp machines generally take about 22 amps, as measured by me. But starting a saw or jointer pegs my ammeter at over 60 amps for 3-4 seconds, and starting my 5 hp bandsaw pegs the ammeter for about 10 seconds (as those heavy wheels get going). But the load when they are just spinning without doing any work/cutting (what we called "friction and windage" when I was an engineering student") is far from a full 5 hp load.

Therefore if you start two motors at the same time (on the same switch) you are very likely to pop a breaker. If you start them 10-20 seconds apart, and only "work" one at a time, you can probably safely run two machines on a circuit that was intended to support one (and your circuit breaker will tell you if it isn't safe).

Dust collectors are a zinger. Unlike a saw, planer, shaper, etc. that make noise for minutes but work for seconds at a time, a dust collector works at full power (moving lots of air) most or all of the time. Closing gates may make the dust collector seem to strain, but it is actually using less power, since it is doing less work, moving less air. But the common idea of putting the dust collector on the same switch as a machine is very bad ... starting two motors at the same instant, and a terrible load on the circuit providing the power.

As I said in another recent post, if your lights dim, you are dropping the voltage. Motors don't do well when the voltage drops. They like high voltage. Get it fixed. But if your lights don't dim, you are probably in pretty good shape. (A good rule of thumb, not scientific proof.)
 
Thanks all. FW is proving it's worth again. I have considered options, including a dive from the cliff along the creek near my house. But, now I think it will be a simple matter. I have a long 10 ga., three wire extension cord I kept when I sold my camper trailer. That will save a few $$$. I'll need a male plug to my lathe box. Those are more expensive than someone quoted. It will be about $35.00. I'll shop for a switch today and call a friend for back up assistance. Final report later.

EDIT: BTW, I am not concerned that the motor might be too heavy for this table saw. The saw is a pretty large affair and quite stout. Hope I'm not wrong but I'm confident it will be OK.
 
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Picked up a male plug connector today at Lowe's but had no luck finding a switch. Couple hours, lots of stops, lots of gas wasted. Trying to be a good citizen and buy locally. Didn't work. :( Ordered from Grizzly, paid with Pay Pal. Quick, easy and efficient.
Mounted the motor. Not a whole lot heavier than the 3/4 hp. I removed. It will be just fine. Put lightweight white grease on the adjustment gears and worm screws while I was at it. When switch arrives a friend will wire up for me although I think it is straightforward enough I could do. But, he wants to help. Now, I'm getting anxious to make sawdust with this monster.
 
Picked up a male plug connector today at Lowe's but had no luck finding a switch. Couple hours, lots of stops, lots of gas wasted. Trying to be a good citizen and buy locally. Didn't work. :( Ordered from Grizzly, paid with Pay Pal. Quick, easy and efficient.
Mounted the motor. Not a whole lot heavier than the 3/4 hp. I removed. It will be just fine. Put lightweight white grease on the adjustment gears and worm screws while I was at it. When switch arrives a friend will wire up for me although I think it is straightforward enough I could do. But, he wants to help. Now, I'm getting anxious to make sawdust with this monster.

When finished Pics please.....
 
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