# Replacement Motor For 14x40 Lathe



## jaychris (Jul 5, 2016)

I've been digging around the archives, but I still haven't found exactly what I need to know.  I suspect it's because I don't really know a whole lot about AC motors in the first place.  Enough to mount and wire one, but spec-wise... not so much.

I have a Jet GHB1440 - when I run the lathe in reverse and it starts to wind down, I can hear some pretty nasty grinding.  Like I said, I don't know motors that well, but it doesn't sound good to me.  It seems fine running in forward.

I figured I would buy a decent Baldor motor and that seems to be the common thread on posts I've found here.  What I am not sure of, is which one to buy.   My current motor is a 2HP and so this Baldor seems to fit the bill:

http://www.baldor.com/catalog/FDL3516TM

I'm just looking for input from guys with more experience than me, before I make a decision.  Also, as long as I am replacing it, are there any other changes/updates I should make at the same time (different belts, isolation mounts, etc...)?


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## 4GSR (Jul 5, 2016)

That should fit the bill.  Check the frame size on your existing motor and make sure it will match up.  The worse that could happen, the new motor frame size could be off slightly.  Nothing that could not be fixed by drill new mounting holes.  The pulley may not fit.  May have to purchase a new one.  Baldor has some nice motors.  Their pricing is sometimes out of reach to some of us.  I'm afraid to ask what they get for the motor?  Shop around, that Baldor motor could be had for a lot lower than the retail price.


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## mksj (Jul 5, 2016)

Bladors are very decent motors and last a long time, but there are many other brands that are also good. It is most likely that the mounting holes and pulley size may be different.  You may also consider going to 3 phase and use a RPC or VFD, but adds to the cost and takes some electrical skills. A 3 phase motor will run smoother, and you will not have any  issues with the start and run capacitors going in single phase motors. Have you tried to run your motor with no belt to see if the noise is there, or it is something in the gear train? Most of the single phase motors are about twice the price of a 3 phase motor, so you could buy a VFD and 3 phase motor for the price of a single phase motor, but then there is the wiring and programming. 

Be aware that electrical boxes are in different positions, most metric motors they are on the top, vs US are on the side.

I would check eBay, you can often find great Baldor deals (with no shipping charge), and also on NOS in other brands. Might consider a 3 Hp motor if you have the space. There are also some killer 3 phase motors for $200-300.  Another single phase Blador motor to consider is the  L3516TM or EL3605T, the T has no overload protection built in, the TM has a thermal overload protector built in. All these are TEFC, sealed motors, the L3516 being general purpose for machinery, the EL3605 is a high efficiency and will draw a tad less current. The farm duty is a beast and is 1800 RPM, but not the most efficient power wise.
http://www.ebay.com/itm/L3516TM-2-HP-1730-RPM-NEW-BALDOR-ELECTRIC-MOTOR-/381147792910
http://www.ebay.com/itm/EL3605T-2-HP-1740-RPM-NEW-BALDOR-ELECTRIC-MOTOR-/201280840933
http://www.ebay.com/itm/BRAND-NEW-M...HP-1755RPM-1PH-60HZ-P-N-EL1408T-/331890308798

FDL3611TM
http://www.ebay.com/itm/BALDOR-2HP-1800rpm-182T-TEFC-1ph-AC-Motor-/291771262107


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## Bob Korves (Jul 5, 2016)

Don't give up on your existing motor too easily.  Sometimes the centrifugal switch slip ring and brush in single phase motors makes noise as it re-engages while slowing down.  That is an easy motor repair, if that is all it is.  If you do not know about motors, it is probably smart to take your existing motor to a local motor shop and have them check it out.  It does not cost much, and may save you lots of time and effort installing a new motor.


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## Ulma Doctor (Jul 5, 2016)

you may simply have a roller bearing failing in the motor. 
i'd rip it out and tear it down for a closer inspection, if it were my lathe.

remove the pulley, mark your end caps position relative to the field winding and remove the retaining bolts.
knock the end caps off and inspect the bearings , being careful when removing the end opposing the shaft side, that's where the centrifugal switch lies.
once the end caps are removed, the rotor can be removed from the field winding for inspection.
extract the bearings from the rotor and replace.
inspect the field windings for signs of damage.
reassemble in reverse order and bench test to make sure you got things correct before installation 
i hope the info is helpful


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## jaychris (Jul 6, 2016)

Bob Korves said:


> Don't give up on your existing motor too easily.  Sometimes the centrifugal switch slip ring and brush in single phase motors makes noise as it re-engages while slowing down.  That is an easy motor repair, if that is all it is.  If you do not know about motors, it is probably smart to take your existing motor to a local motor shop and have them check it out.  It does not cost much, and may save you lots of time and effort installing a new motor.




Thanks, maybe I'll do that before dropping the coin on a new motor.


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## jaychris (Jul 6, 2016)

Ulma Doctor said:


> you may simply have a roller bearing failing in the motor.
> i'd rip it out and tear it down for a closer inspection, if it were my lathe.
> 
> remove the pulley, mark your end caps position relative to the field winding and remove the retaining bolts.
> ...



It's definitely helpful.  I may not know a lot about motors, but I have no problem at all jumping into one.  The worst I can do is break it and then buy a new one and I'll have learned something along the way.

I'll take a short video of the noise and maybe you guys can identify the issue just from the sound.  If it's something simple like you say, I'll take a shot at it.


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## Ulma Doctor (Jul 6, 2016)

jaychris said:


> It's definitely helpful.  I may not know a lot about motors, but I have no problem at all jumping into one.  The worst I can do is break it and then buy a new one and I'll have learned something along the way.
> I'll take a short video of the noise and maybe you guys can identify the issue just from the sound.  If it's something simple like you say, I'll take a shot at it.



the only thing i ask is,
that if you come to a place when you do not know how to proceed, in either disassembly or reassembly, ask someone how to go along. (either me or other fine gents here)
i'm happy to help you learn.
*WARNING: *there may be potential electrocution risk if you play with the capacitor.
 see the video i made a while ago below:


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## jaychris (Jul 6, 2016)

Ulma Doctor said:


> the only thing i ask is,
> that if you come to a place when you do not know how to proceed, in either disassembly or reassembly, ask someone how to go along. (either me or other fine gents here)
> i'm happy to help you learn.
> *WARNING: *there may be potential electrocution risk if you play with the capacitor.
> see the video i made a while ago below:



Yep, I know electronics (and hence, testing/discharging capacitors), but appreciate the warning.    Just never torn down an AC motor.


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## Ulma Doctor (Jul 6, 2016)

sorry, i didn't mean any offence . my concern was for your safety 
this can be your very first time to rip one down!


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## jaychris (Jul 6, 2016)

Ulma Doctor said:


> sorry, i didn't mean any offence . my concern was for your safety
> this can be your very first time to rip one down!



Absolutely none taken!  The first time I forget might be the last time, so it's always worth hearing a warning.


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## 4GSR (Jul 9, 2016)

Mike,

Thanks for the short video on shorting out capacitors.  I learned at a early age what capacitors can do to you if you are not paying attention, give you one heck of a jolt of electricity!  Luckily, it was a very small capacitor.  I've built several static type of phase converters over the years, grouping various size capacitors together for use in them.  When you have several electrolytic capacitors grouped together in parallel, things get very excited shorten them out to work on a converter.  I get gun shy every time I have to shorten a group of them out.  Some of the ones I've built have the resistor across the tabs, but even then, I've shorted one or two that still had juice in them. 

People, be careful handling them and follow Mike's advice on discharging them.


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## Tony Wells (Jul 9, 2016)

I'm an anti-screwdriver discharge guy. I don't like to see the current spike when you just arc one out. I prefer a resistor and a couple of clips. Really doesn't take long, and is safe for you and the cap.


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## tertiaryjim (Jul 9, 2016)

If you have a single phase motor now is it driven by a VFD ?
You probably already do so but from what I've read the lathe should come to a complete stop before reversing.
Also the motor sheave can make noise if it gets loose.  Gotta loosen the belts to check it and while the belts are loose try running the motor with no belts and check the load end for play.


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## John Hasler (Jul 9, 2016)

The current spike when discharging an electrolytic capacitor won't hurt it.  The only things that damage them are over-voltage and heat.  They are somewhat nonlinear and have a relatively large esr so running too much AC through them for too long will cook them but a single isolated pulse does no harm.

Something to watch out for: electrolytics have a sort of "memory effect".  Charge one to its full rated voltage, hold it there for a bit, discharge it to zero, wait a bit, and you may find that it now has a significant voltage on it.


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## Tony Wells (Jul 9, 2016)

I must respectfully disagree with John on this one. Every capacitor has a charge/discharge design factor. They are limited to prevent damage to not only the foil anode material, which can suffer from heat, but also the electrolyte composition can be changed. Net effect generally is a shortened life.  This is even reflected in the design frequency at which they can operate. Too high a frequency can kill them. In effect, when you short across them (which I have done - guilty) the operating frequency is infinitely high, even for one cycle. There are formulas to determine how fast a cap can safely (and I mean without harm to the capacitor) be brought to theoretical zero, which is an interesting topic of it's own. It's only milliseconds, but nonetheless, it is a factor that is specified by the mfg. and declared safe.

Now if you don't care if you shorten the life a little, and don't mind a notch in your screwdriver......go for it. I'll use a resistor.

Per Nippon-Chemi-com....mfg of electrolytic caps.

John, no argument intended, just presenting the facts as I understand the mfg design and intent. I respect what you say and your expertise.


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## Ulma Doctor (Jul 10, 2016)

What ever method suits you, 
*PLEASE,* just short a cap before attempting any service!


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## mksj (Jul 10, 2016)

Concur with Tony Wells, I build tube gear with high voltage power supplies, always use a bleeder resistor to bring down the charge in a capacitor. After discharge, I might short the capacitor just before removal to dissipate any memory/residual charge. The capacitors can hold a charge for a long time, so do not assume that since you haven't used a machine for awhile that the capacitors are discharged. When dealing with banks of capacitors, there is a tremendous amount of charge held in the capacitors unless there is some form of bleeder resistors across the terminals, and even then they can take some time to fully discharge. When I purchase old high voltage military oil can type capacitors, they always come with a wire across the terminals when packaged new.

From another source: Electrolytic capacitors may become permanently damaged by excessive peak currents with rapid discharge/charge, which will definitely occur during short-circuit events. The reason is that (a) the internal resistance will cause a momentary, but large power dissipation (heat!) and (b) the distribution of the current spike inside the capacitor will not be formed evenly across the large area of the aluminum foil and hot spots may occur. The electrolyte may vaporize along these small zones and damage to the insulating aluminum oxide layer may occur as well. If you're lucky, the capacitance will decrease just a bit or the top of the can may change its shape into something like a dome. If you're very unlucky, the cap may fail and heat up quite a bit (and eventually blow). This applies to different types of capacitors, not just electrolytic types.


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## jaychris (Jul 10, 2016)

Sorry for the delay, but here is a short video of my motor when the issue occurs:

https://drive.google.com/file/d/1m7kPxYW8mMWfpAG4RCi6WsjlG4eEl_cRPg/view?usp=sharing


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## Ulma Doctor (Jul 10, 2016)

sounds to me like it's in the centrifugal switch assembly, others may have different opinions.


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## jaychris (Jul 10, 2016)

Ulma Doctor said:


> sounds to me like it's in the centrifugal switch assembly, others may have different opinions.



Is that worth replacing yourself (if it's field replaceable) or is it new motor time?


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## Ulma Doctor (Jul 10, 2016)

it might be as simple as re-lubricating the actuator.
i'd take a peek, if it were mine.


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## John Hasler (Jul 10, 2016)

jaychris said:


> Is that worth replacing yourself (if it's field replaceable) or is it new motor time?


It's worth taking it apart and looking.  Sometimes they're just gummed up.


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## tertiaryjim (Jul 11, 2016)

+1


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