Lathe (AC) motor questions

[Bill Leonhardt]

I am putting a lathe online and I wish to get comments about the motor choi ce and control.

I am recently retired and have been collecting various AC motors over the y ears with the thought that I would employ them for various jobs in my shop. I am setting up a wood lathe (Rockwell/Delta 14-11x48, model 46-111) and need a motor to power it. My two best candidates are as follows:

Motor 1- Craftsman ½ HP capacitor motor, 1750 rpm, 115V, 60 cy, 8.2A. It has a shaft out each end so rotation direction is not a problem.

Motor 2 ? Craftsman 500/5000 rpm, 60 cy, 1 ph, 115V, 15A, ½ HP max. Duty cycle: Hi speed cont./ Lo speed intermittent. Speed control k now on opposite end of motor from shaft. Rotation direction is opposite fo r use on the lathe (without the motor sticking out and in the way) and I tr ied to switch wires to see if I could change direction, but NG.

I also have the following devices:

Variac Autotransformer W5MT, one side common line and load, 50-60 cy, line

120V, load 0-140V, 5A.

2000W AC50-220V SCR High Power Voltage Regulator Module, 25A max.

Questions:

1. I know that there are various flavors of AC motors (capacitor start, un iversal, ?). Can anyone explain the difference or point me to a go od web reference to understanding the differences of AC motors and how, if possible, to cjange their rotation direction?

1. The speeds on the lathe are controlled by stepped pulleys. I? m thinking I might be able to also control speed by using the Variac or SCR . Would that damage the motor or even work in this case?

2. For the variable speed Craftsman motor, would there be a way to revers e the rotation? If so, and I ran it at say half speed, how would the term ?intermittent? apply?

Looking forward to your wisdom, thanks,

Bill Leonhardt

[Clare Snyder]

Use the 1/2 HP capacitor motor. Neither motor can be used as variable speed with either the Variac or SCR voltage regulator. You would need a variable frequency drive to effectively control the speed of an AC induction motor - and even then, you would really want a 3 phase motor to get decent starting torque. (the Variable Frequency Drive would create 3 phase power from single phase)

The 500/5000 RPM motor is variable speed, not just 2 speed? with a speed control KNOB? Is it like this one?

If so it is a "universal" motor or a DC motor running with a built in silicon rectifier, and the duty cycle would vary with the speed output - continuous at full speed, down to about a60% at half speed. You would want to have the pulleys set up so it runs at full speed for normal use - I would not use it without the stepped pulleys, depending on the speed control for total speed control because GENERALLY your lower speed jobs will require MORE torque than your high speed. In other words you will need full horsepower, and since horsepower is the product of torque and speed, running the motor at lower speed without higher torque output produces less power - even if the motor continues to produce the same torque (which they seldom do - and if they do they run HOT - which is why the duty cycle is reduced.

[Bill Leonhardt]

hoice and control.

e years with the thought that I would employ them for various jobs in my sh op. I am setting up a wood lathe (Rockwell/Delta 14-11x48, model 46-111) a nd need a motor to power it. My two best candidates are as follows:

A. It has a shaft out each end so rotation direction is not a problem.

HP max. Duty cycle: Hi speed cont./ Lo speed intermittent. Speed contro l know on opposite end of motor from shaft. Rotation direction is opposite for use on the lathe (without the motor sticking out and in the way) and I tried to switch wires to see if I could change direction, but NG.

ne 120V, load 0-140V, 5A.

universal, ?). Can anyone explain the difference or point me to a good web reference to understanding the differences of AC motors and how, if possible, to cjange their rotation direction?

?m thinking I might be able to also control speed by using the Variac or SCR. Would that damage the motor or even work in this case?

erse the rotation? If so, and I ran it at say half speed, how would the te rm ?intermittent? apply?

Claire,

Thanks for your reply. The variable motor I have is similar to the picture in the link you sent without the green remote plug. It does have the rota ting knob to set the speed. In any case, it sounds like I should give up w anting to control the speed electronically and just use the stepped pulleys alone.

[swalker]

How much do you plan on selling this lathe for?

[Bill Leonhardt]

hoice and control.

e years with the thought that I would employ them for various jobs in my sh op. I am setting up a wood lathe (Rockwell/Delta 14-11x48, model 46-111) a nd need a motor to power it. My two best candidates are as follows:

A. It has a shaft out each end so rotation direction is not a problem.

HP max. Duty cycle: Hi speed cont./ Lo speed intermittent. Speed contro l know on opposite end of motor from shaft. Rotation direction is opposite for use on the lathe (without the motor sticking out and in the way) and I tried to switch wires to see if I could change direction, but NG.

ne 120V, load 0-140V, 5A.

universal, ?). Can anyone explain the difference or point me to a good web reference to understanding the differences of AC motors and how, if possible, to cjange their rotation direction?

?m thinking I might be able to also control speed by using the Variac or SCR. Would that damage the motor or even work in this case?

erse the rotation? If so, and I ran it at say half speed, how would the te rm ?intermittent? apply?

Please forgive my choice of words. By "putting on-line", I meant I was get ting it ready for my use as a lathe, not selling it.

I've had this lathe for many years when I got a chance to buy it at a reaso nable price, but I had never gotten a chance to set it up. I am now retire d and got as far as replacing the bearings and mounting it on a stand. Set ting up a motor is all that is left to be operational.

[Scott Lurndal]

I suspect your best option is to go with motor 1 and select the shaft pully such that you get a 5:1 or 4:1 reduction on the largest of the stepped pullys. The idea is for the slowest speed to be around 500 RPM.

In the old wide-belt days on the farm, we'd figure-8 the belt to reverse the direction of rotation. Not sure that would work well with a V-belt.

[Dr. Deb]

oice and control.

years with the thought that I would employ them for various jobs in my sho p. I am setting up a wood lathe (Rockwell/Delta 14-11x48, model 46-111) an d need a motor to power it. My two best candidates are as follows:

. It has a shaft out each end so rotation direction is not a problem.

HP max. Duty cycle: Hi speed cont./ Lo speed intermittent. Speed control know on opposite end of motor from shaft. Rotation direction is opposite for use on the lathe (without the motor sticking out and in the way) and I tried to switch wires to see if I could change direction, but NG.

e 120V, load 0-140V, 5A.

universal, ?). Can anyone explain the difference or point me to a good web reference to understanding the differences of AC motors and how, i f possible, to cjange their rotation direction?

?m thinking I might be able to also control speed by using the Variac or SCR. Would that damage the motor or even work in this case?

rse the rotation? If so, and I ran it at say half speed, how would the ter m ?intermittent? apply?

Bill, I have not looked at your motors, but one thing you absolutely need i s a TEFC motor, otherwise the dust will ruin the motor.

[Jack]

Absolutely is a strong word. Most of my stationary tools are circa

1954, including my Rockwell lathe, do not have TEFC motors and have been running for that many years. The motors now are inclosed in there respective cabinets except for the contractors saw.

The contractors saw is the only one that ever had a problem. It got packed with saw dust and needed pulled apart and cleaned or the starter switch gets stuck. 30 years ago I put a nylon stocking over the cooling vents to keep out large chunks and it's been running fine with nary a glitch.

I might add that I'm pretty sure Rockwell sold these tools with the motors, which always seemed odd to me. Didn't they have TEFC motors back then?

Not saying you shouldn't use TEFC motors, but I "absolutely" know my motors have been running for over 60 years w/o them, and no fires, no nothing other than the TS issue 30 years ago.

To the OP, I've been running stepped pulley's on my lathe since forever, as have millions of turners. Variable speed motor would be nice, but not even close to necessary. Make sure your belt is loose enough to make moving it around easy. As a bonus, the belt slips under a jam.

[Bill Leonhardt]

ed is a TEFC motor, otherwise

Jack,

Thanks for your words about TEFC. I also have experienced a motor that wou ldn't work due to saw dust buildup. My Walker Turner contractor-like saw ( easily 60-80 years old) had a vented motor. Compressed air works wonders, especially when you know the symptoms/cure.

Even though I have stepped pulleys, and a 1725 RPM motor, I thought the low speed was a little fast for some of my operations. Of course, that may be because I am a very inexperience turner and I'll probably get braver with more experience. I also now realize that my hoped for solutions resulted i n an unacceptable loss of torque at the low RPM setting.

I shall mount my motor and work out some convenient lever/cam design to eas ily take the tension off the belt. I also will use the motor weight to giv e the belt tension.

Thanks to all who responded.

Bill

[Leon]

I guess the question to answer here is do you actually use your equipment enough to warrant having a TEFC motor. Length of owner ship means nothing for a non TEFC motor if you do not use the tool every day or at least several days a week. It is highly likely that if dust is getting into a motor over a 60 year period of high use there are going to be issues.

Any time dust or wood chips fall directly onto a motor a TEFC motor is going to be the better choice if you expect it to hold up over time.

[Jack]

The point I made is that "absolutely" need is a strong word. I doubt Bill is going to earn his living on his lathe, turning 40+ hours a week. The second point I made is if your motor is enclosed in a cabinet, like mine is, dust is a non-issue for the hobbyist turner, and probably the professional turner. The first 20 years my motors were fully exposed on a standard open tool stands, not a cabinet. Same with the TS, BS, Jig saw, and jointer. Jig saw, Drill Press and TS motors are still exposed. Shaper, Dust collector and sander are TEFC. Never had any problems with any of them other than the TS, cured with nylon stocking.

Can't speak for the guy that owned my tools the first 20 years, but up until recently, my tools saw regular use. Not commercial use where tools run constantly 8-24 hours a day, 7 days a week. That's a totally different animal. None of my tools, motors (or user) are designed for that. I doubt the OP plans on using his lathe in a commercial environment either. Even single user commercial use your tools most likely run very little over the course of a day, or even a project.

Better choice for sure, *absolutely* needed, not so much. Ergo the nylon stocking over the vents on my contractors saw motor, which does get lots of fine sawdust spewed directly over the vents. Before the nylon thing, the TS motor would get packed with saw dust to the point the motor switch would not engage and I'd have to rip it down and clean it up. My other motors have never had an any issues.

[Jack]

Compressed air works wonders, especially when you know the symptoms/cure.

inexperience turner and I'll

My experience is you're correct. With a bit of experience, you'll be turning at higher speeds, even when roughing out spindles. Slow speeds are used for roughing out off balance bowls, off center spindles for the most part. Extreme slow speeds you can get with variable speed motors are probably most often used with really large off balance turnings. I always wanted a variable speed motor, but never really needed one. I believe 99% of my turning time uses just two speeds, the second and third steps on the pulley's. Often I only change the step on one pulley which really puts slack on the belt, but it still turns w/o a problem.

I once threw away a treadmill and later thought, damn, I bet the variable speed motor would have worked great on my lathe...

Yes, good idea. I saw a motor mounted on a wood plate that was hinged to the table so it got all it's tension from the weight of the motor. Seemed perfect for a lathe using stepped pulley's.

My lathe motor is just bolted to a little two legged "table" bolted to the cabinet. You could adjust the table height with shims if needed to get the tension just right.

[Dr. Deb]

ed is a TEFC motor, otherwise

But, whether or not a TFEC motor is required depends on where its located. Put an unenclosed motor right in the path of dust coming off a lathe and y ou will have problems. The motors you are talking about are enclosed, with the exception of the table saw, which did have problems.

Can you run an unenclosed motor? Sure. But an enclosed motor is just less prone to problems.

[Jack]

Well none of my stationary tools were enclosed in a cabinet for the first 20 years of their life. I built cabinet stands for them and now the motors are enclosed. My jig saw, drill press and TS are still not enclosed. Only the table saw had a problem and so far, that was eliminated simply with a nylon stocking over the vents. I've not needed the nylon stocking solution with any tool other than the TS. If Bills motor gives him a problem with dust he can grab a nylon stocking rather than run out and buy a new, TEFC motor. When that fails, he can run out and buy a new motor, which in my experience won't be for around 60+ years from now...

Just pointing out my experience with non-TEFC motors in my shop. It stands to reason if buying a motor for a dusty environment, you would go for TEFC motors. On the other hand, telling Bill he *absolutely must* use a TEFC motor on his lathe is counter to my 40 years experience with these tools, and 60 years experience for the tools themselves.

No, my tools are not used constantly as they might in an industrial setting, but over 60 years, they have seen plenty of use, certainly far more than enough to contradict the 'absolutely must use TEFC motor' statement.