Motor Questions

[Alan Lightstone]

OK, I'm somewhat at a loss here.

I have a Laguna 12" Jointer/Planer, with supposedly a 3HP motor, which has stopped turning its motor. If I open the back of it, sometimes I can turn the pulleys by hand and get it going, other times it starts slowly and eventually gets up to power. Usually at this point, it just doesn't start.

Tech support thinks the start capacitor has gone bad. Here's the problem, though. I can't find a start capacitor. It has what I think is a run capacitor on it, which is 40MFD at 450V. There is no other capacitor visible on the motor (I have removed it from the unit, so I get a full view).

Also, there is no identifying motor plate on the motor, so who knows what HP it really is, and who the manufacturer is, and I think that's likely not a good sign.

Any suggestions where to go from here? Is it possible that the motor does not have a start capacitor and just has a run capacitor? Would it then be likely that the run capacitor is the cause of this?

[Chris Padilla]

Sure, it could only have a run cap. The easiest thing to do is to take your capacitor to a local motor supply house/fix-it place and see if they can match it up for you.

[John Lanciani]

Hi Alan, if there is only one capacitor it is a starting cap. An induction motor does not need a run cap, it is only used to increase efficiency where the start capacitor is necessary to get the motor turning in the correct direction. Your symptoms are classic start cap failure since the motor will run when you help it start.

[Alan Lightstone]

John, Chris:

When I look at the section on motor capacitors on wikipedia (yeah, yeah, insert comment here), it says that start capacitors are always over 70 MFD and have four major voltage classificationa 125V, 165V, 250V, and 330V. None of these are 450V and 40MFD, which seems to line up with their descriptions of run capacitors.

Also, could a local motor supply shop determine what the HP rating of the motor is? I'm just not happy about no motor identification plate. I've never seen that.

[Mike Henderson]

Hi Alan, if there is only one capacitor it is a starting cap. An induction motor does not need a run cap, it is only used to increase efficiency where the start capacitor is necessary to get the motor turning in the correct direction. Your symptoms are classic start cap failure since the motor will run when you help it start.
John's right. Single phase induction motors need a starting capacitor. If that's the only one capacitor on the motor, it has to be the starting capacitor.

And as he points out, if you can get the motor to run when you "start" it by hand, that's almost a sure sign the starting cap is bad. Replace the cap and see what happens. They're not very expensive.

The capacity of the start capacitor is usually not critical, once you pass a certain minimum microfarad size.

Mike

[John Lanciani]

Wikipedia...always...:rolleyes:

I don't suspect that the Chinese (or the Italians if it happens to be a CEG motor) follow what Wikipedia says they are always supposed to do. I have seen caps with the 450V rating though. Like Mike said, get one as close as you can find and give it a shot.

[Bruce Wrenn]

PSC motors only have a run capacitor. Furnace fans use these as starting loads are small. The fan in my Delta (AP-400) only uses a 50 uf capacitor. When it puked it's guts, fan wouldn't come up to speed. Substituted a 40uf I had on hand, and it was "off to the races."

[David L Morse]

Is it possible that the motor does not have a start capacitor and just has a run capacitor?

Well, a single phase induction motor has to have some means of starting. It's certainly possible to use a single capacitor for both starting and running. This is called a Permanent Split Capacitor (PSC) motor. There's no centrifugal switch. The main disadvantage of this setup is fairly low starting torque, but a jointer/planer doesn't offer much of a load at start.

If your cutter head is jammed up a bit though the extra load could be beyond the starting capabilities of a PSC motor so be sure to check this.

Also, I assume you have already checked this but loose pulleys or belts can show similar symptoms.


Also, could a local motor supply shop determine what the HP rating of the motor is? I'm just not happy about no motor identification plate. I've never seen that.

I see that a lot on imported equipment. The horsepower rating of a motor depends upon the temperature rating of the insulation, the expected lifetime and the thermal dissipation capabilities of the motor housing. It's not something you just measure on a dynamometer. A good motor person could eyeball it or compare DC resistance measurements to other motors and give you an educated guess but I'm not sure what you would do with that information. Can you calculate a required HP knowing material type, width, cut depth, feed rate and duty cycle?

[Robert Delhommer Sr]

Sounds like a bad start capacitor.

[Alan Lightstone]

The only reason I'm interested in the HP rating of the motor is to make sure it really is the 3HP motor I paid for.

I've got the motor out in a box, and am going to bring it in to a local motor place. Laguna sent me a quote for the capacitor, which was quite reasonable (don't get me started about my local AC contractor that just charged me 6 times that for an identical capacitor (and they will lose a customer over it). That being said, since I pulled the motor, I don't mind the extra expense (just as long as it's reasonable) for the motor place to test the motor and replace the capacitor.

I may drive a Tesla, but Nikola's knowledge of AC motors has not rubbed off on me by just driving one.:)

[Alan Lightstone]

Well, a single phase induction motor has to have some means of starting. It's certainly possible to use a single capacitor for both starting and running. This is called a Permanent Split Capacitor (PSC) motor. There's no centrifugal switch. The main disadvantage of this setup is fairly low starting torque, but a jointer/planer doesn't offer much of a load at start.

If your cutter head is jammed up a bit though the extra load could be beyond the starting capabilities of a PSC motor so be sure to check this.

Also, I assume you have already checked this but loose pulleys or belts can show similar symptoms.



Actually, it was when I opened the machine to tighten up the loose pulleys that the problem first presented itself.

The cutter head isn't jammed. It's the first thing I checked, but good point.

What does a centrifugal switch look like? Is it inside the motor itself, because I don't see one.

[Bill Adamsen]

Also, I have had good luck shopping for and buying start capacitors on ebay. It makes it more of a commodity.

[Mike Henderson]

Actually, it was when I opened the machine to tighten up the loose pulleys that the problem first presented itself.

The cutter head isn't jammed. It's the first thing I checked, but good point.

What does a centrifugal switch look like? Is it inside the motor itself, because I don't see one.

Even if you can't see it, you should be able to hear it when the motor slows down when you power it down. Run the motor with no load and then turn it off. As the motor slows down, you'll hear a definite "snap" or "click" which is the centrifugal switch closing. If you don't hear that, you either don't have a centrifugal switch (maybe it's a permanent split capacitor motor), it's very quiet, or it's stuck.

Mike

[I don't know why they would put a permanent split capacitor motor on a jointer/planer, but you never know. The size and the voltage rating would lead you towards that alternative. But maybe the cap has been changed earlier.]

[Dan Friedrichs]

Do a google image search for centrifugal switch, and you'll see several examples. You can usually hear them click in and out, as well.

Your motor almost certainly has a centrifugal switch and a start capacitor. PSC motors are not as common, and I don't think I've ever heard of one >2HP.

I suppose it's possible that someone put the wrong value start cap on your motor (but as Mike says, it's not a critical value, so maybe it worked).

I'd start by replacing the cap with a roughly identical one and see what happens.

[Allan Speers]

The capacity of the start capacitor is usually not critical, once you pass a certain minimum microfarad size.
Mike


True. However I think you want to find a cap series that can handle a high inrush current, so "just any" cap in that range may not be ideal. There may also be other beneficial electrical characteristics that I'm not aware of.

Maybe Mike or someone else can recommend a good brand & series to use. (I'd kinda' like to know myself.)

[Mike Henderson]

True. However I think you want to find a cap series that can handle a high inrush current, so "just any" cap in that range may not be ideal. There may also be other beneficial electrical characteristics that I'm not aware of.

Maybe Mike or someone else can recommend a good brand & series to use. (I'd kinda' like to know myself.)
The starting capacitor causes a phase shift of the current in the starting coil. It needs to be of a high enough capacity (microfarad) to pass sufficient current to generate a sufficiently large magnetic field in the starting coil to generate sufficient starting torque - but not so large that the current passed would cause excess heat in the coil. Since the starting coil is only energized for a very short time (usually) that gives you a wide range (in other words, there's not much time for heat to build up).

The "ideal" size (microfarad) of the capacitor depends on the motor design. So my recommendation would be to choose a starting cap that is close to the failed one you have. If you have a choice of voltage rating, choose the same voltage rating or higher. I suppose a higher voltage rating would make the cap physically larger so make sure it will fit.

As far as brand, I don't have any insight. I had a starting cap fail in my dust collector recently (cheap Chinese cap) and I replaced it with a cap of a recognized brand. Right now, I don't remember the brand or where I got it. I do remember it was not that expensive. I suppose one reason I don't remember much is that I didn't put a lot of thought into buying a new cap. Just looked for a brand name cap close to the same microfarad and voltage and bought it.

Mike

[Just an additional note: A capacitor passes AC current but blocks DC. The amount of current passed depends on the frequency of the AC and the size (microfarad) of the capacitor. So the motor designer will choose a capacitor size (microfarad) that will pass sufficient current (at either 50Hz or 60Hz, depending on the design of the motor) to start the motor.]

[Alan Lightstone]

Thanks for the explanation, Mike. Very interesting.

It appears that identical 40MFD, 450V capacitors are commodity items and easy to obtain, so I'll take that route and see how it works.

[David Kumm]

Let us know what the motor shop thinks of the motor. I've found they have ( especially the old guys ) an opinion on every motor they look at. It is getting more common to leave info off the motor as supplying cheap offshore motors with poor efficiency and crappy windings are a way to cost reduce a machine. Even higher end companies are substituting lesser motor quality. Dave

[Alan Lightstone]

Let us know what the motor shop thinks of the motor. I've found they have ( especially the old guys ) an opinion on every motor they look at. It is getting more common to leave info off the motor as supplying cheap offshore motors with poor efficiency and crappy windings are a way to cost reduce a machine. Even higher end companies are substituting lesser motor quality. Dave
Yup, that's basically my concern. He may not open the motor if everything checks out OK after replacing the capacitor and testing the motor, but I asked him to try to tell if it's 3HP. I'll ask him what he thinks of the quality.

Long-standing AC motor repair company, so their experience may yield some interesting information.

[Allan Speers]

Thanks, Mike.

I still do think that surely some series of cap would be better suited to this application than others, but I'm probably over-thinking it.

(What else is new? :) )

[David L Morse]

Thanks, Mike.

I still do think that surely some series of cap would be better suited to this application than others, but I'm probably over-thinking it.

(What else is new? :) )

Sure, it's called a Motor Start capacitor, but I suspect you already knew that.:) There's an industry spec covering them called EIA RS-432 so compliance with that is what you need to look for on the data sheet.

Here's some information (http://pdf.searchdatasheet.com/datasheets-1/barker_microfarads/091A021B110AC1A.pdf) about the qualification testing in EIA RS-463. Note that it is NOT the spec itself but part a capacitor manufacturer's data sheet that has reprinted some of the spec.

Some study of the duty cycles in the test condition tables can help with understanding one of the reasons why you should be careful with how often you start a motor.

[Alan Lightstone]

Interesting, David.

Reading the document would lead me to believe that the capacitor that was placed on the motor was not a motor start capacitor, but probably should have been. Being a 450V capacitor, none of the motor start capacitors has that voltage rating, and none have nearly that high a capacitance at 330V.

Is the fact that it may be the wrong type of capacitor the cause of its failure? Who knows? The capacitor is 6 years old, and gets intermittent not heavy use. Again, who knows?

Until recently, the motor ran just fine.

As far as what is the correct capacitor to place on the motor, hopefully the motor repair specialist will use the correct one, instead of just replacing whats there and may be wrong, but lacking any motor plate or identification, for him the wise move is probably just to replicate whats presently in place, but has likely failed.

Definitely makes you wonder about Laguna's parts sources...

[David L Morse]

Interesting, David.

Reading the document would lead me to believe that the capacitor that was placed on the motor was not a motor start capacitor, but probably should have been. Being a 450V capacitor, none of the motor start capacitors has that voltage rating, and none have nearly that high a capacitance at 330V.

Is the fact that it may be the wrong type of capacitor the cause of its failure? Who knows? The capacitor is 6 years old, and gets intermittent not heavy use. Again, who knows?

Until recently, the motor ran just fine.

As far as what is the correct capacitor to place on the motor, hopefully the motor repair specialist will use the correct one, instead of just replacing whats there and may be wrong, but lacking any motor plate or identification, for him the wise move is probably just to replicate whats presently in place, but has likely failed.

Definitely makes you wonder about Laguna's parts sources...

The European equivalent to EIA RS-463 is IEC 60252-2. It covers Motor Start Capacitors up to 660V.

I don't have a copy of RS-463 so I don't know how high it's voltage ratings go. The pdf I linked was one manufacturer's offerings.

[Mike Henderson]

Good information, David. Thanks for posting that link.

Mike

[I found it interesting that they recommended mounting the cap with terminals up, rather than down. I'll have to go check how I mounted the one I put on my DC.]

[Alan Lightstone]

Well, some news from the AC repair guy.

Yes the capacitor was faulty. But also the bearings are bad (never heard anything there, but I may have not known what to look for), and the windings are burnt (not sure what that means).

He strongly suggested that replacing the motor would be less expensive than fixing it. He also noted that the mounting holes on the motor are non-standard, so asked if I could drill out new mounting holes (which I could, but will clearly be a pain).

So it sounds like a new motor is in the cards. Any suggestions how to drill out the cast iron mounting plate for new mounting holes? Any comments as to the cause of the motor woes?

Any idea what a good 3HP, 220V, 1phase motor goes for? A Baldor or what other good choices are there? How many RPM should the motor be rated for (I see 1200, 1800, and 3600 RPM as choices).

Induction? General Purpose? Not clear what the best choices are.

Is the configuration with both start and run capacitors better than just ones with start capacitors, or does this not matter.

Again, this is for a Laguna 12" jointer/planer.

Lots of questions, I know, but I think many will learn lots about AC motors from some of the experts here.

[John Lanciani]

Most likely a metric frame motor, what is the shaft diameter? If it is metric, you either have to do as suggested and make a nema frame fit or bite the bullet and pay the higher price for a metric motor. If you adapt, you will probably have to get a bastard pulley with an imperial bore and metric belt pitch ( probably spz or xpz belt pitch if it's metric)

[Alan Lightstone]

I'll have the motor guy measure the shaft diameter for me tomorrow.

From what I'm seeing, am I correct in assuming that normal shaft diameter is 1-1/8"?

[Mike Henderson]

Well, some news from the AC repair guy.

Yes the capacitor was faulty. But also the bearings are bad (never heard anything there, but I may have not known what to look for), and the windings are burnt (not sure what that means).

He strongly suggested that replacing the motor would be less expensive than fixing it. He also noted that the mounting holes on the motor are non-standard, so asked if I could drill out new mounting holes (which I could, but will clearly be a pain).

So it sounds like a new motor is in the cards. Any suggestions how to drill out the cast iron mounting plate for new mounting holes? Any comments as to the cause of the motor woes?

Any idea what a good 3HP, 220V, 1phase motor goes for? A Baldor or what other good choices are there? How many RPM should the motor be rated for (I see 1200, 1800, and 3600 RPM as choices).

Induction? General Purpose? Not clear what the best choices are.

Is the configuration with both start and run capacitors better than just ones with start capacitors, or does this not matter.

Again, this is for a Laguna 12" jointer/planer.

Lots of questions, I know, but I think many will learn lots about AC motors from some of the experts here.

I'm not sure what he means that the windings are "burnt". Normally, that would happen only when the motor got excessively hot. As long as the insulation is good on the windings I'd run the motor. If the insulation has failed, you'll have windings of the field shorted to other windings. When that happens, the shorted winding(s) will act like a transformer and excess current will flow in the shorted windings, leading to the motor overheating. And overheated electrical motor wiring produces a very distinctive smell.

I'd get a replacement capacitor and then run some tests on the motor. Hook it to your Jointer/planer and buy a 2x4 and plane it down to a toothpick. Then feel and smell the motor. If it's not excessively hot and you don't smell anything, I'd use the motor. I might replace the bearings but I'd keep the motor and use it until it failed (started smoking or smelling of hot insulation).

In general, induction motors either work or they don't. Motors don't catch fire - in my experience. They smoke or smell really strong and then they won't start, even after you let it cool down. You're going to be present any time the motor is used so you'll know if the motor starts to smoke or smell.

Mike

[Alan Lightstone]

There was a slight smell the last time I used it. I had attributed it to the pulleys slipping, but that may have not been the case.

[Mike Henderson]

There was a slight smell the last time I used it. I had attributed it to the pulleys slipping, but that may have not been the case.
If the motor won't start and you leave it powered, it will overheat. But that often does not cause disabling damage. I'd do the test I suggested and see what happens. If the motor gets excessively hot, you haven't lost anything - you still have to buy a new motor. It it runs fine, at a minimum you'll be able to put off getting a new motor until this one really fails.

I had an induction motor on an air conditioner (fan) overheat - severely overheat (won't go into how that happened but I would have burned my fingers on the motor) - I thought it was fried. But the weather was hot and it would take me a day or more to get a replacement motor. So I let it cool down (fixed the reason it overheated) and when I powered it up again, it ran. At first, I thought I'd just use it for a few days until I could get a new motor. But as the days passed, the motor kept working and I kept putting off spending the money for a new motor - those 240V AC fan motors are pretty expensive. I never replaced the motor and years later, I sold the house and the A/C fan was still working fine.

Mike

[John K Jordan]

Actually, it was when I opened the machine to tighten up the loose pulleys that the problem first presented itself.

Could you have tightened a belt or something too much? Just wondering.

BTW, the capacitor on one of my small lathes (Jet mini) went out. It was 25uF 250v. The symptoms were it would always start if I spun it by hand, and would sometimes start by itself. With the capacitor blown the lathe was just as likely to run backwards as forwards. If it didn't start, there was an audible hum from the motor.

When the capacitor went out it made a strong and unpleasant smell and it looked warped and overheated.

I assume you checked the wiring for a loose connection or broken wire. That would give the same symptoms of a fried capacitor.

If you order a capacitor make sure it will physically fit in the housing. The Jet capacitors are so ridiculously overpriced that some people bought a different capacitor that didn't physically fit and mounted it some other way.

JKJ

[Alan Lightstone]

Further info from the motor repairman. He said that the windings are definitely fried, and just replacing the capacitor won't work.

i had tightened the pulleys, but only to factory specs, so if that was the cause (it likely was, and certainly was temporally) that would rot.

He did not measure the shaft diameter, but he did say it wasn't metric, and the mounting bolt locations weren't standard either. He said it must be a custom made, no-name OEM unit made for Laguna. Oh joy!!!

He's looking into options for me, and will let me know in a few days.

[Jim Dwight]

This probably is not it but the 1 hp (true 1 hp, draws 15A) induction motor I had on my old home-made table saw was not sealed. The motor slots would fill with sawdust occasionally and I would have to tear it down and blow the dust out. When they were clogged, it did what you describe. It is a capactor start motor. If you have it at a repair shop, they should see this if it is a contributor or the problem. It should be a sealed motor so this should not be the issue.

[Alan Lightstone]

Should be a TEFC sealed motor.

BTW, since I have to replace the motor anyway, is there an advantage to putting in a 5HP motor instead of the 3HP motor that's in it?

There is room, and my AC circuit can handle the extra power.

[Dan Friedrichs]

I'm really surprised you "burnt" the windings. Are you sure you trust the motor guy? I'd get the motor back from him and see for yourself - burnt windings would be obvious (they'd look like the coils on the stator - the outer part - had been on fire). Posting a picture here would help. I'd also double-check his claim about the bearings. Grab the shaft and lift up/down - bad bearings would cause play in the shaft.

If you want to replace it, you can certainly go bigger (5HP), but the cost goes up quickly. 3HP should be plenty. Even a 3HP motor is pricey - $300-$500 for a Leeson or Baldor.

Obviously, go with a TEFC motor. Speed should be whatever speed gives you the correct speed on the cutterhead (so it will depend on the pulleys, etc).

There is no difference between motors with just a starting cap vs motors with start and run caps.

[Alan Lightstone]

I'm really surprised you "burnt" the windings. Are you sure you trust the motor guy? I'd get the motor back from him and see for yourself - burnt windings would be obvious (they'd look like the coils on the stator - the outer part - had been on fire). Posting a picture here would help. I'd also double-check his claim about the bearings. Grab the shaft and lift up/down - bad bearings would cause play in the shaft.

If you want to replace it, you can certainly go bigger (5HP), but the cost goes up quickly. 3HP should be plenty. Even a 3HP motor is pricey - $300-$500 for a Leeson or Baldor.

Obviously, go with a TEFC motor. Speed should be whatever speed gives you the correct speed on the cutterhead (so it will depend on the pulleys, etc).

There is no difference between motors with just a starting cap vs motors with start and run caps.
Lots of good info, Dan. Thanks.

I don't know if I trust the motor guy. But if he wanted to rip me off, he would have pushed repairing the motor, which he isn't.

Let's see what he comes back with for options for a new motor, etc...

[Mike Henderson]

Stick a starting cap in it and see what happens. You have nothing to lose but the cost of a capacitor - which is pretty low.

Mike

[Alan Lightstone]

OK. Time to re-evaluate my options.

The motor repair guy called back. He basically said that a big issue is that the pulley is not standard size ID (since the motor shaft is unusual size OD), so that with a new motor they will have to bore out the inside of the pulley also. Between that and replacing the motor (he was quoting only 2HP motors, as he said that the outside dimensions of 3HP motors are greater than the one I have) are now in the ballpark of just rewinding the motor, replacing the bearings and capacitor.

Time to reassess my options. I'm going to get back the motor, buy a capacitor from grainger or Amazon, and test it out. If that doesn't work, I can either buy an identical motor from Laguna (although if it has no motor plate, I'm going to be very skeptical that it is a 3HP motor), or buy a Baldor or Leeson motor and have some machine shop bore out the present pulley or find a new compatible dual pulley with the correct ID and OD to get the speed correct.

Also not terribly anxious to get inside this machine to drill new mounting holes for the new motor.

Anyone know a good source of pulleys, and I'm assuming that they are very specific regarding ID, OD, and width for different belt sizes? It's a dual belt pulley, FWIW.

[Malcolm McLeod]

The old motor, whether metric or NEMA, has a frame size - hopefully it IS a standard. The frame size dictates the shaft diameter, length, and any key-way, as well as the bolt size/spacing/pattern for mounting. If you can determine its frame size, it will make any replacement a little easier. Sounds like you have options and contingencies for the motor well planned, so will just offer some options for the drive.

If you have to change motor frame, but want to keep the driven sheave and belt as-is, there are two pieces of data you need for driver: 1) pitch diameter (PD) of the drive sheave (not the same as its OD); and 2) the belt (cross section) profile. Most sheaves and belts have this stamped on them, but either Laguna or a Grainger-like shop should be able to ID for you.

You can spec a new sheave for a replacement motor using the PD, v-belt profile/count, and bore (match to shaft). Or, if you're worried about future motor 'transitions' (i.e. a screamin' deal on a used motor that might last 2 weeks...), for slightly more $$ you can get a sheave with correct PD and v-belt specs, but get it with a QD bore. A QD bushing then adapts the sheave to the motor shaft. If the motor shaft has to change for whatever reason, you just spec a new bushing - - not the entire sheave. QD is very common in large sizes for sheaves, but if your's is too small, the QD option may be impossible. ...hope it helps.

(I like QD, but there are other options - split taper, taper lock etc.)

[David Kumm]

This thread teaches a lesson when buying machinery. Motors are an area where there is a lot of cost cutting. Smaller frame with lots of wire ( good insulation allows this ) allows for lighter weight, less strength to base and guts of machine. Smaller shaft and bearings, etc. The problem is that these motors run hotter, as do the bearings so it is important to look at the motor as more of a temporary part than a forever one. Means you must check that it can be either readily replaced, has a standard frame, has HP (kw ) appropriate for a standard replacement. There are 90 frame metric motors in machines that provide 10 hp but try to find a replacement over 5.5. If the motor isn't standard or high hp for the frame size, can it be rewound reasonably? Motor guys hate packing lots of wires into a small frame or rewinding a small diameter long body motor and the cost go up exponentially. If you are forced to buy a replacement from the machine company, you are doomed. If sales people can't give you the origin, frame size, bearing size, and efficiency, find a sales guy who can. If we don't ask and expect answers for slightly more technical questions, we will be responsible for the reduced quality. Dave

[Alan Lightstone]

This thread teaches a lesson when buying machinery. Motors are an area where there is a lot of cost cutting. Smaller frame with lots of wire ( good insulation allows this ) allows for lighter weight, less strength to base and guts of machine. Smaller shaft and bearings, etc. The problem is that these motors run hotter, as do the bearings so it is important to look at the motor as more of a temporary part than a forever one. Means you must check that it can be either readily replaced, has a standard frame, has HP (kw ) appropriate for a standard replacement. There are 90 frame metric motors in machines that provide 10 hp but try to find a replacement over 5.5. If the motor isn't standard or high hp for the frame size, can it be rewound reasonably? Motor guys hate packing lots of wires into a small frame or rewinding a small diameter long body motor and the cost go up exponentially. If you are forced to buy a replacement from the machine company, you are doomed. If sales people can't give you the origin, frame size, bearing size, and efficiency, find a sales guy who can. If we don't ask and expect answers for slightly more technical questions, we will be responsible for the reduced quality. Dave
Live and learn....sigh.....

[Alan Lightstone]

OK. Back in town, and I got the motor back. The motor repair guy left the housing open, so I can see the windings, which do indeed look burnt. Here's a photo of them:

345286345287345288

So, I'm no expert, but they look burnt to me, though I don't know what they're supposed to look like.

He was not impressed by the quality of the windings or the quantity. He is very doubtful that the motor is indeed 3HP as billed.

Again, he is saying a total rebuild, and replacement of the capacitor and bearings will run about $650.

Laguna said they have a replacement motor for me for $311 with shipping. I will try to pin them down and insist that the motor have an appropriate motor plate on it that says 3HP, but I am skeptical. Also skeptical about the quality of the motor from them. The first one is impressing no one.

I'll work on measuring the dimensions later, both of the mounting holes and the motor, shaft, and exterior dimensions, to see if people think just buying a quality 3HP motor and having a metal shop bore out the pulley to the correct diameter would be a better idea.

I'm wondering what everyone's collective thoughts on my best approach going forward.

[Malcolm McLeod]

I'm wondering what everyone's collective thoughts on my best approach going forward.

Get a windmill powered machine..??? Looks like FLA won't have electricity for a while.

I know you're on the opposite coast, but keep you head down. A fleet of utility trucks, linemen, and power poles left here at 6AM, headed in your general direction. I hope you don't need them! Take care.

On hopefully more useful note, I'd just buy a new sheave to fit motor if req'd. Machining a new bore is probably about break-even with buying new, and 'new' has no concerns about balance, concentricity, keyway, etc.

[Jerry Bruette]

Alan

Do you have room to put in a adapter plate, metal plate that would have holes drilled like your present motor and another set of holes drilled for a standard NEMA frame motor? The holes for your present motor would be through holes and the NEMA ones could be tapped.

Then you could purchase the appropriate sheaves and probably never have to mess with it again.

I would check with the surplus center for a motor. They may even have the sheaves you need.

[Alan Lightstone]

Jerry:

Interesting thought. I'm a little confused on nomenclature. Is a sheave what I am think of as a pulley?

The motor guy today said that the pulley on my motor was very custom with the two belts very close to one another. I'm thinking that I'll have to have the present pulley reamed out to the proper NEMA dimensions, instead of being able to find a compatible pulley.

[Mike Henderson]

OK. Back in town, and I got the motor back. The motor repair guy left the housing open, so I can see the windings, which do indeed look burnt. Here's a photo of them:

345286345287345288

So, I'm no expert, but they look burnt to me, though I don't know what they're supposed to look like.

He was not impressed by the quality of the windings or the quantity. He is very doubtful that the motor is indeed 3HP as billed.

Again, he is saying a total rebuild, and replacement of the capacitor and bearings will run about $650.

Laguna said they have a replacement motor for me for $311 with shipping. I will try to pin them down and insist that the motor have an appropriate motor plate on it that says 3HP, but I am skeptical. Also skeptical about the quality of the motor from them. The first one is impressing no one.

I'll work on measuring the dimensions later, both of the mounting holes and the motor, shaft, and exterior dimensions, to see if people think just buying a quality 3HP motor and having a metal shop bore out the pulley to the correct diameter would be a better idea.

I'm wondering what everyone's collective thoughts on my best approach going forward.
That does not look burnt to me. As I recommended before, put a starting capacitor on it and try it out. You won't know unless you try, and you aren't risking much by giving it a try.

Mike

[Alan Lightstone]

OK, Mike. I'll give it a shot.

Ordered capacitor.

It certainly would be simpler if the motor repair guy was dishonest. I guess I'll find out in a few days when the capacitor arrives. Certainly will be much simpler than dealing with a new motor / mount / shaft size.

[Mike Henderson]

Good luck! I hope it works.

It's hard to tell from pictures but I've seen worse on working motors.

Mike

[Jerry Bruette]

Jerry:

Interesting thought. I'm a little confused on nomenclature. Is a sheave what I am think of as a pulley?

The motor guy today said that the pulley on my motor was very custom with the two belts very close to one another. I'm thinking that I'll have to have the present pulley reamed out to the proper NEMA dimensions, instead of being able to find a compatible pulley.

Pulleys and sheaves are the same. Why not switch to standard A or B groove sheaves, then your belts are easier to source and possibly cheaper.

[Dan Friedrichs]

Looks like it got a little hot (the string holding the windings appears to have burned apart in a few spots), but I agree with Mike that it will probably work fine.

[Alan Lightstone]

Interestingly, I did a bunch of measurements on it last night. It appears to by a NEMA type 56 motor by the mounting hole dimensions and shaft height, but the shaft diameter is strange. It is a slotted shaft with an OD of 0.788" (20 mm).

I haven't looked for a metric equivalent to the NEMA chart yet, but perhaps it will show up there.

Interestingly, when I called Laguna, the tech seemed very surprised that the motor had no motor plate (not surprised as I was, I assured him). If I need a replacement motor from them, he assured me that he would confirm that it was 3HP. He also is very surprised that the motor only has one capacitor. So god knows what OEM crap motor they put in an expensive machine in 2009 when they built the machine. Doesn't say much about the company.

Let's say I'm skeptical. I have yet to find a 3HP motor with those mounting dimensions. All NEMA type 56 motors I have found max out at 2HP, which is what I think this motor they sent with the machine is.

If I need to replace it, a type 143 would fit (but I can't find over 2HP in that either), or a type 145 is readily available in 3HP versions (I would have to modify the width of the mounting plate only, not the length, which I guess wouldn't be that bad. Plus, get the pulley bored out to 20mm.

But I'm still hoping that the capacitor change will fix things.

[David Kumm]

Will the Laguna guy give you the face plate info off his replacement? I'm not surprised if the motor is claimed to have more hp than a standard for that frame size. That is fairly routine in Europe. Wind a smaller frame with additional wire to allow them to claim extra hp or kw. Makes replacing them difficult. If the new motor is $300 is isn't all that great as replacement motors are almost always overpriced relative to quality. The motor plate would help you a lot. Dave

[Jerry Bruette]

Interestingly, I did a bunch of measurements on it last night. It appears to by a NEMA type 56 motor by the mounting hole dimensions and shaft height, but the shaft diameter is strange. It is a slotted shaft with an OD of 0.788" (20 mm).

I haven't looked for a metric equivalent to the NEMA chart yet, but perhaps it will show up there.

Interestingly, when I called Laguna, the tech seemed very surprised that the motor had no motor plate (not surprised as I was, I assured him). If I need a replacement motor from them, he assured me that he would confirm that it was 3HP. He also is very surprised that the motor only has one capacitor. So god knows what OEM crap motor they put in an expensive machine in 2009 when they built the machine. Doesn't say much about the company.

Let's say I'm skeptical. I have yet to find a 3HP motor with those mounting dimensions. All NEMA type 56 motors I have found max out at 2HP, which is what I think this motor they sent with the machine is.

If I need to replace it, a type 143 would fit (but I can't find over 2HP in that either), or a type 145 is readily available in 3HP versions (I would have to modify the width of the mounting plate only, not the length, which I guess wouldn't be that bad. Plus, get the pulley bored out to 20mm.

But I'm still hoping that the capacitor change will fix things.

Surplus Center has 55 3HP 56 frame motors in stock, and they're rated for continuous duty.

[Alan Lightstone]

Surplus Center has 55 3HP 56 frame motors in stock, and they're rated for continuous duty.

Interesting. Is an open drip motor acceptable in that application (in a cabinet, where sawdust isn't supposed to enter)? Will this motor have enough torque for a 12" jointer / planer.

http://www.surpluscenter.com/Catalog/Catalog289-152.pdf

And would the 5HP motor above it on that page work as well (although I'll cry, as I just had the electrician rewiring in that area of my workshop and could have had him change that circuit to 30 amps yesterday)?

And isn't this just the same deal of a manufacturer stuffing a ton of windings in a small motor so that they can claim the higher horsepower, though it's really not designed properly?

That being said, what a great price!

[David Kumm]

A higher hp motor will also entail replacing the starter. Make sure the shaft is long enough to accept the pulleys. I've never had great luck with cheap motors but that doesn't mean they won't work. I wouldn't go through the time and expense of changing or reboring pulleys, and electrics and then installing a cheap motor. I'd rather go with a used Baldor or the old Marathons make in WI. My motor guy tells me that when buying a single phase Leeson he recommends the red farm duty motors. Best bang for the buck. Most smaller ones are Chinese but there is some level of QC. Dave

[Alan Lightstone]

So, the winner is.....

Mike Henderson. And John Lanciani, and Robert Delhommer, and a few others...

I replaced the capacitor (still unclear by its rating if its a start or run capacitor, but whatever, I replaced it). the motor runs like a charm. Almost silent. No sounds of bearings, no burnt winding smell. Just a working motor.

Now I'm going to have to modify the capacitor case, as my new capacitor is slightly larger. And lift this heavy motor back onto its mount, and put back the four bolts. Two pulleys later, tension it properly, close it up, and hopefully as good as new.

Take home lessons:

1.) The jointer manufacturer put a cheap, underpowered motor in the jointer with no motor plate and unusual dimensions for shaft and mounting. Won't be buying anything from them again. Incidentally, I check the motor from the bandsaw that I purchased from them also. Identical dimensions, also supposed to be 3HP, also unlikely to be what I paid for. As I said before, will never buy from them again.

2.) The local motor repair shop was trying to rip me off. I can understand their angle, but he did it in such a weird way as to ensure that I wouldn't do the repair there. Saying that the windings were burnt, and the bearings were shot was clearly false. Won't be using or recommending them to anyone again.

3.) The best advice, as is the norm, came from the great members of this forum. So many times I have asked for advice here (and given some, when I can), and invariably Sawmill Creek members and moderators have been incredibly helpful. Thanks to one and all.

[Art Mann]

You can get some insight into the HP rating of the motor by measuring the current under full load, computing the wattage and then converting directly from watts to horsepower. You will need to multiply the result by .8 or so to account for poor efficiency.

[Mike Henderson]

Thanks for your kind words. The tip off was that you said that if you gave the motor a spin, it would run. That's almost 100% an indication of a bad starting capacitor.

Regarding the HP of your motor, Art gave some good advice, but it's hard to load the motor to full load - or for that matter, to know when you're at full load. Another way is to measure the motor and then compare the measurements to other motors of known HP (and same RPM). Motor technology is such that all motors of the same HP and RPM are about the same physical size.

Mike

[But if the motor works fine in your application, don't worry about the HP rating.]

[Just to be sure, after you get it installed, I'd do something to load it down - maybe get a 2x4 and joint it over and over. Then turn the unit off and feel the motor to see how hot it is. You should be able to put your hand on it. That it, it may be hot, but not so hot that you'd burn your hand. If so, I'd be convinced the motor is fine.
If you could measure the current while you use the jointer, that would tell you something, also. But feeling the motor is probably sufficient.]

[Alan Lightstone]

So, the final outcome.

Replacing the capacitor fixed the problem. It is a run capacitor, best I can determine, there is no start capacitor. Yes I know, makes no sense. Unless that is a run capacitor that is being used as a start capacitor.

Oh and on the customer service angle, Laguna's rep never got back to me with the availability of a replacement motor. Good thing I didn't need it. As usual, their customer service...