Repowering SB 9" Lathe
Repowering SB 9" Lathe
I acquired an old SB 9" lathe this week as a basket case, and re-assembled it last night. It's been re-motored with a Dayton 1/3HP motor and it seems like it's a bit tired. Also, wiring isn't right I'm only getting reverse.
I got a 25% mothers day coupon in the mail from horrible freight, so I'm looking hard at their 1HP motor for a repower.
The attached picture is the wiring diagram for the 1HP motor, I'm just wanting to confirm that I'll basically use a DPDT action at the switch to flip flop T8 and T5 for FWD and REV, and that L2 *stays hot* because T8 and T5 are the "starting coils" for one direction or another?
I need to map my rotary switch, but at first look it appears to have 3 sets of contacts that are closed in either direction. So I could use two of them to swap T8 and T5 and the 3rd to switch the hot line L2.
I got a 25% mothers day coupon in the mail from horrible freight, so I'm looking hard at their 1HP motor for a repower.
The attached picture is the wiring diagram for the 1HP motor, I'm just wanting to confirm that I'll basically use a DPDT action at the switch to flip flop T8 and T5 for FWD and REV, and that L2 *stays hot* because T8 and T5 are the "starting coils" for one direction or another?
I need to map my rotary switch, but at first look it appears to have 3 sets of contacts that are closed in either direction. So I could use two of them to swap T8 and T5 and the 3rd to switch the hot line L2.
Re: Repowering SB 9" Lathe
Yes, you are just swapping T5 and T8.
Dave
Dave
- Bill Shields
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Re: Repowering SB 9" Lathe
Hf motor?
Smooth motors make good surface finishes on lathes.
Not sure hf motive power will qualify.
My experience with them has included
Bad centrifugal switches
Bad caps
Bad bearings
Loose bearings on shafts and in housings
Crappy uneven windings causing motors to 'cog'
Run out on output shafts.
Basically anything that can be done to make a cheap motor.
Use one to drive a sump pump or attic circulation fan....maybe....but a lathe?
Sale coupon or not. .think I would look elsewhere.
Smooth motors make good surface finishes on lathes.
Not sure hf motive power will qualify.
My experience with them has included
Bad centrifugal switches
Bad caps
Bad bearings
Loose bearings on shafts and in housings
Crappy uneven windings causing motors to 'cog'
Run out on output shafts.
Basically anything that can be done to make a cheap motor.
Use one to drive a sump pump or attic circulation fan....maybe....but a lathe?
Sale coupon or not. .think I would look elsewhere.
Too many things going on to bother listing them.
Re: Repowering SB 9" Lathe
Bill, I agree and I generally avoid much of harbor freights stuff. The 1HP motor seems to have a good following though, lots of people using them on custom belt sanders grinders and lathe repowers (The 1hp is fan cooled and sealed) with good reviews posted several years after install. Unfortunately a lot of things are only made in China anymore and there's probably a dozen + brands selling the same motor.
I picked it up last night and it appears it's going to bolt right up in place of the 1/3rd HP Dayton. It's the same frame and shaft size, so this weekend we'll find out how well it works. It's not in the cards to spend more than I did on the lathe for a Baldor instant start/reverse motor.
I picked it up last night and it appears it's going to bolt right up in place of the 1/3rd HP Dayton. It's the same frame and shaft size, so this weekend we'll find out how well it works. It's not in the cards to spend more than I did on the lathe for a Baldor instant start/reverse motor.
Re: Repowering SB 9" Lathe
Blink! Blink! You're kidding, right Bill?
I can think of little that would be as annoying as an attic fan that kept the entire house rumbling.
I ran an American made single phase motor on the fan for my fume hood, which often ran 24/7. Damned thing hunted constantly and was quite annoying. There's nothing quite as nice as a three phase motor.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: Repowering SB 9" Lathe
Thing is, I bought this to mainly flip the compound around and cut all my large scale train wheel angles. I'll be feeding by hand so I don't know how good of finish I'm going to get and the wheels are going to rust anyway. For other stuff where I'm running the power feed, sure I can see any hunting in the motor resulting in variance in finish. We'll see what happens it should be up and running sometime this weekend.
Re: Repowering SB 9" Lathe
I don't see the single phase motor, even a rough one, being of any consequence. What Bill alludes to is quite true when you're going for fine finishes and close tolerance, though. That's especially true for precision grinders, where a single phase motor is likely to show in the finish, no matter what you do.
H
H
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: Repowering SB 9" Lathe
Unless you have bought hundreds of the HF motors I'm calling BS on all those failures and if you did buy hundreds and had those failures, I think you must have not been thinking. Most of us would have quit buying junk after the second one with a failure like you mention.Bill Shields wrote: ↑Fri May 08, 2020 5:02 am Hf motor?
Smooth motors make good surface finishes on lathes.
Not sure hf motive power will qualify.
My experience with them has included
Bad centrifugal switches
Bad caps
Bad bearings
Loose bearings on shafts and in housings
Crappy uneven windings causing motors to 'cog'
Run out on output shafts.
Basically anything that can be done to make a cheap motor.
Use one to drive a sump pump or attic circulation fan....maybe....but a lathe?
Sale coupon or not. .think I would look elsewhere.
- Bill Shields
- Posts: 10605
- Joined: Fri Dec 21, 2007 4:57 am
- Location: 39.367, -75.765
- Contact:
Re: Repowering SB 9" Lathe
No reason a single phase should hunt more than a 3 phase under a steady load..unless is a crappy motor to begin with.
I have tried two hf motors..one for a bench grinder that had all the above defects except one. The replacement had the off center shaft.
I have tried two hf motors..one for a bench grinder that had all the above defects except one. The replacement had the off center shaft.
Too many things going on to bother listing them.
Re: Repowering SB 9" Lathe
I'm not sure that's true, Bill. Single phase motors don't have the overlap of power pulses that are enjoyed by three phase. The average voltage remains much higher with three phase due to the 120° phase overlap, as there's never a point where there's 0 voltage, unlike single phase. I have **never** experienced hunting with a three phase motor, and I own a large number of them, running in all manner of conditions (variable loads) as I've had three phase service at all of my residences since 1967.Bill Shields wrote: ↑Sat May 09, 2020 5:51 am No reason a single phase should hunt more than a 3 phase under a steady load..unless is a crappy motor to begin with.
I will agree that the motors I've experienced from China are of exceedingly low quality. In some cases, like the little cheapo cement mixer, the huge motor housing (relatively speaking) hides the scanty amount of metal within. It hunts like crazy, loaded or not. However, it has done everything asked of it in my building project. A good value for the guy not mixing 'crete daily.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
- Bill Shields
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- Joined: Fri Dec 21, 2007 4:57 am
- Location: 39.367, -75.765
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Re: Repowering SB 9" Lathe
I think you will find that a single phase motor hunting is the result of a bad motor design more than the fact that it is a single phase motor.
No argument about 3 phase being a superior concept
No argument about 3 phase being a superior concept
Too many things going on to bother listing them.