thoughts on failed minimax saw motor

[joe milana]

So I just sold my 4 y/o 5 hp single phase Minimax S315 Elite S slider, and purchased a vintage martin. (huge upgrade!) The saw was used strictly to size 3/4" ply for cabs, and had very light use. Plenty of other saws for other tasks. Maybe 12 houses worth of cabs in 4 years. (I'm slow) My cutting style was typically setup, turn saw on, make cut, turn saw off, repeat. Never ran the saw for more than a minute or so.
So the kid that bought the saw just told me the motor burned up after a week of use. He said the saw would run for 30 min., then trip the overload. Motor was HOT! Replaced the run cap & the saw ran "beautifully", then the same thing. I never ran the motor that long. SCM says windings are probably bad and new motor is recommended. Man, that sucks. I've never had a motor go bad on me, so I guess I'm just looking for insight as to why this may have happened. I know the euro motors typically run a bit hotter, but with overload protection, you'd think the motor would be, well, protected.

[Bill Dufour]

The way you ran it is very hard on a motor. Most motors are rated for about 15 starts per hour. Air compressor motors more then that. Starting currents can be 4x run currents so much heating at each start cycle.
Bill D.

[joe milana]

doubt I ever came close to 15 starts in an hour. (did I mention I was slow?)

[Jim Becker]

The only time I had an issue with the motor on my S315WS shutting down was when there was a problem with voltage being provided from the street. I got a buck/boost transformer to fix that and it's very, very rare that I have an internal breaker let go. Maybe once a year.

[joe milana]

I suggested voltage, but he said it was "fine" Whats a good way to monitor voltage? Especially over a 30 min period. Any unusual circumstances that cause the trip? Ie. cutting thick hard wood, etc.

[Rod Sheridan]

"HOT" means different things depending upon whether you're a motor or a person.

A motor in normal operation will be far too hot for you to put your hand on it. A class B motor will have a maximum insulation temperature of 130C, the case may be 90 to 100C, far too hot for you to touch.

It's possible that the motor overload isn't set properly, and has tripped when it shouldn't have.

I would check that, the line voltage while the saw is cutting and the run capacitor, also of course, check for loose connections...........There's probably nothing wrong with the motor.........Rod.

[Darcy Warner]

Typical small frame metric motors. I have had more bad motors on scmi stuff than any other equipment. Fiamec motors are junk.

[David Kumm]

Joe, I'd pull the motor and have it tested. Five years is short for even a small frame metric motor. My experience with those motors is similar to Darcy's, but like you, most of my stuff is older. I'm sure your Martin motor has a much larger frame. That is pretty new for a rewind issue though. Dave

[joe milana]

If the motor is bad, are there alternatives to buying one from scm?

[Warren Lake]

darcy always hope you are wrong, have a bunch of those motors but so far no issues other than some bad wiring on one of the SCM which was known years later.

[David Kumm]

Joe, you can find a similar frame motor with hopefully capacitors in the right location. The issue may be finding them with the same HP rating. SCMI will use a 100L motor rated at 9 hp but you are lucky to find a replacement at 5-7 hp in the same frame size. I've had motors rewound and it might be a cheaper option but I've also found that motor shops don't like rewinding some of those small frame motors and charge a lot. I've had quotes ranging from 500-1200 for a SCMI three phase 9 hp motor. My motor guy isn't a big fan of Italian or Chinese motors but tells me the Techtop motors are not bad. Short fat motors are cheaper to rewind than small diameter long motors. Again, you might get lucky and find problem that can be fixed but I've not been so lucky. I've had more Euro motor issues than in any of my old US machines but my sampling method isn't scientific. Dave

[joe milana]

According to SCM, the motor had a bad run cap, which likely caused the motor to over amp & Run extremely hot, ruining the winding. I'm surprised the motor would run with a bad run cap.

[Warren Lake]

joe if it has a cap it single phase? all my experience with Italian stuff is three phase SCM Griggio

[joe milana]

Warren, this is a SCM minimax hobby saw. 5hp single phase.

[Warren Lake]

okay im likely working on the big brother of that now older 20 years approx or a bit more. I cant fault alot of the construction its not really heavy like the british stuff, sort of in the middle, I wonder when i look at newer stuff if its made as heavy. They have a number of lines though as well up to the Invincible stuff thats what my older stuff is.

[glenn bradley]

Like others my knee-jerk reaction is ‘line voltage’. It is odd that it functioned so well for you for so long, is moved to a new location with a new source voltage and things go south. When I sell things I sell them “as is, where is” for just this reason. However, like you I would feel some responsibility in following up to see what the cause was. If you have the wherewithal I would have the motor tested. Depending on how trustworthy the person who bought it is, you may just tell them to go and have it tested.

[Erik Loza]

Just my thoughts, not that they matter: Something like 208V + stopping/re-starting machine every 2-3 minutes = Unhappy motor. I sold as many S315's as anyone and cannot remember a truly bad motor. Caps, yes, but can't recall a single bad motor. Just my 2-cents. Motor is probably CEG, by the way.

Erik

[David Kumm]

It might be informative if a single phase motor guy here would talk about how a faulty start or run cap could damage a motor, how long it would take, how to identify the problem, and how to test to avoid it. I'm a three phase guy so I have little experience with these issues. Maybe others can help.

Joe, I understand your concern with an after the sale issue, kind of like the inserts I owe you. Dave

[Warren Lake]

These days an attitude like Joes is nice to see.

[joe milana]

it might be informative if a single phase motor guy here would talk about how a faulty start or run cap could damage a motor, how long it would take, how to identify the problem, and how to test to avoid it.

^^^this^^^

[Peter Kelly]

If the motor is bad, are there alternatives to buying one from scm?Recent model MiniMax sliders would more than likely have shipped with a CEG motor as opposed to a FIMEC. Might give them a call to see if they can either re-wind it or sell a replacement to the current owner.

CEG North America
Tel: 800-223-5557
http://www.cegmotors.com/contact.html

Replacements are also available from Parts Pronto if you're cool with being gouged by SCM.

Edit: just saw Erik mentioned the same above. Check with CEG anyway.

[Darcy Warner]

I have had 3 100 frame motors rewound. One 4.8kw and two 6.6kw. They were 600.00 each. 50 bucks cheaper than a replacement from SCM and was done quicker than the shipping time from Italy.

I am sure the single phase would be close to the same price.

[Rod Sheridan]

Hi, as I indicated in my original post, it's most likely that there's not a fault with the motor.

It runs for 30 minutes before tripping the overloads.

I would start with the items I listed in my post rather than replacing the motor without an accurate diagnosis.

It would be good to measure the motor current under load to determine if there is a motor problem...............Rod.

[Jamie Buxton]

I suggested voltage, but he said it was "fine" Whats a good way to monitor voltage? ....

Measure it with a voltmeter. You can buy one for $15 at any big box store.

It is true that a single-time measurement will not monitor voltage over time. But it will identify gross issues, like the 208 vs 230 one.

[Malcolm McLeod]

Hi, as I indicated in my original post, it's most likely that there's not a fault with the motor.

It runs for 30 minutes before tripping the overloads.

I would start with the items I listed in my post rather than replacing the motor without an accurate diagnosis.

It would be good to measure the motor current under load to determine if there is a motor problem...............Rod.

^+1 - A motor issue would typically be obvious (i.e. trip the O/Ls) in 30sec or less. 99% of the bad motors I've seen will trip a properly set O/L in 2-3sec or less.

I would want to know more about the current user's process: What's the max loading they're applying? What's their duty cycle?

[Malcolm McLeod]

Measure it with a voltmeter. You can buy one for $15 at any big box store.

It is true that a single-time measurement will not monitor voltage over time. But it will identify gross issues, like the 208 vs 230 one.

If you spend a few extra bucks, you can get a multi-meter and a clamp-on amp probe. You'll be an 'expert' (almost;)). Many multi-meters have a 'min/max' feature that captures the low and high values measured in a given period of time.

Based on a severe lack of information, but allowing for their 30 minute run time, my first suspicion is that the user is over-loading the saw. If their process is to load 8 3/4" sheets of MDF on the saw with a 100' 16ga extension cord, a 16" blade, and a 3hp motor (...no, I didn't look up the specs), then rip it to 1" widths while the lights dim in every cut - - then I'd guess it's not the motor? I've never used a slider, but can't help but think I'd overload it too, given the ease of material feed.

[David L Morse]

...Replaced the run cap & the saw ran "beautifully", then the same thing...

I think it would be worth taking a look at that capacitor again. A run capacitor has to be rated for continuous duty. Start capacitors are for intermittent use. If a run capacitor is replaced with a start capacitor the motor will run properly for a while until the capacitor overheats and fails.

[Charlie Plunkett]

I would agree with Rod, before pulling the motor check for bad connections or small extension cord, bad plug or outlet, also is the motor a TEFC, the fan could be broken, missing blades, lose on the shaft vents blocked, after all that is checked if you have a amp meter clamp it around one of the power leads, is the amps higher the name plate rating while it is at idle, or are the amps
fluctuating by 3 to 4 amps I do not know your setup but is the saw driven by a belt if so then could your arbor bearings be bad? Also how about your motor bearings are they bad. 30 minutes of running to me dose not sound like a bad motor,these are things I would look for when I use to do service work on electric motors

[Matt Mattingley]

Hi, as I indicated in my original post, it's most likely that there's not a fault with the motor.

It runs for 30 minutes before tripping the overloads.

I would start with the items I listed in my post rather than replacing the motor without an accurate diagnosis.

It would be good to measure the motor current under load to determine if there is a motor problem...............Rod.
I’m pressing the like button. Run capacitors and start capacitors are two different animals. Most start capacitors average between 7-10 starts per hour, to stay happy. Usually if A capacitor is shot, the overloads will trip in under 10 seconds. If the overloads have tripped to many times, the overloads could be faulty.

If Rod is on board answering electrical questions, I usually don’t double guess him, as is the most brilliant electrical guy I know.

[Martin Wasner]

I wish I understood electricity better.

If it were me, I'd pull the motor and take it to a motor shop. Split the bill with the dude who bought it. A few months ago my dust collector popped all three fuses in the control cabinet. Turned out a bad bearing took out the windings. $600 later the motor was rewound and rebuilt.
Plus another $350 to balance the fan. That was a 20hp Baldor. I think I had it back in two days.

[joe milana]

Motor is at the shop. Waiting for diagnosis. Once again, SCM's "over the phone" diagnosis was : If the motor was run for long periods of time with a bad run cap, then the motor would run "out of phase", and amperage would be excessively high, causing winding failure.

[joe milana]

Just heard from the guy. Motor shop said "motor starter" in the motor was dirty. I'm assuming he meant centrifugal switch. Said windings were fine. He re-installed the motor & said it's pulling 20amps at idle, which SCM says is high. Motor shop said is fine.
I asked if he ever checked the contacts in the mag starter, and he said no. He didn't know the saw had one. Once again, it's 5hp single phase.

[David Kumm]

Life is good- for now. Dave

[joe milana]

Any idea if that saw has a mag starter?

[joe milana]

Motor badge
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[Larry Edgerton]

Unplug the saw when it is running, plug it back in, if it starts it does not have one. I had a single phase Minimax that did not.

[David Kumm]

Usually a mag starter will have momentary contact buttons and a manual will have maintained contact ones. What Larry says to test. Dave

[joe milana]

thanks. It has momentary switches. I'll have him do the unplug test. Cant believe SCM or motor shop has not said a word about mag starter.

[Mike Kreinhop]

My 3-phase SC2 has a Siemens 3RV2011-1HA10 circuit breaker that serves as the On-Off switch and provides the thermal overload protection for the motor. It also uses a Siemens 3RV2902-1AV0 Undervoltage Release to enable the breaker when everything is set up correctly or to trip the breaker when the emergency stop button is pushed or the side guard is opened. Unlike a classic motor starter circuit that uses push buttons, a contactor, thermal contacts, and a latching contact in series with the contactor coil, the Siemens circuit breaker has a mechanical latch that works when the knob is turned, unless the Undervoltage Release prevents the circuit breaker from closing. This is the main reason why relocating the start switch or adding a remote switch to the Minimax is not possible without replacing or bypassing the factory installed circuit breaker...which is what I will eventually do.

I suspect the S315 has something similar. When power is applied to the saw, and all of the safeties are in the normal mode, you should here a "click" as the Undervoltage Release activates to enable the circuit breaker. If you start the saw and unplug it, the saw will stop. If you then plug it back in, it will not restart because the Undervoltage Release tripped the circuit breaker in the saw and it must be manually reset by turning the knob to the Off position before you can start it again.

[joe milana]

Thanks for that. That's exactly what this saw has. Now to determine if it is serviceable. ie. Can the contacts be accessed & cleaned?
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The saw is currently pulling 20amps unloaded (tested with Klein ring meter). SCM says it should pull about 8-9amps unloaded & is still convinced the motor is bad. I suggested he "hardwire" the motor directly to the circuit. bypassing all the saws electrics & measure then. That will give us a baseline & rule out any other component of the saw being bad. We'll see what happens.

[Rod Sheridan]

Hi Joe, is the run capacitor working?

With the saw running what's the current in the run capacitor?

Regards, Rod.

[Dan Friedrichs]

Joe, I may be seeing it wrong, but I don't think your picture of that starter is what Mike is talking about. Yours looks like a regular magnetic contactor.

Mike's probably looks something like this: https://mall.industry.siemens.com/mall/en/WW/Catalog/Product/3RV2011-1HA10

[joe milana]

Hi Joe, is the run capacitor working?

With the saw running what's the current in the run capacitor?
Regards, Rod.
Not sure how to check current in the run capacitor. Motor shop said caps either work, or they dont, and this one is fine.



Joe, I may be seeing it wrong, but I don't think your picture of that starter is what Mike is talking about. Yours looks like a regular magnetic contactor.

Mike's probably looks something like this: https://mall.industry.siemens.com/mall/en/WW/Catalog/Product/3RV2011-1HA10

Thanks Dan, yeah, I downloaded some info on the part shown, and I was thinking it looked like a normal contactor as well.

He "hard wired" the saw to the source, bypassing the saws electricals, and it still pulls 18amps at no load. Scm says it should be ~9.

[Rod Sheridan]

Not sure how to check current in the run capacitor. Motor shop said caps either work, or they dont, and this one is fine.




Thanks Dan, yeah, I downloaded some info on the part shown, and I was thinking it looked like a normal contactor as well.

He "hard wired" the saw to the source, bypassing the saws electricals, and it still pulls 18amps at no load. Scm says it should be ~9.

Hi, to check the current in the run capacitor use a clamp on AC ammeter, around one of the capacitor wires.

Is the capacitor the correct value? Wouldn't be the first time I found the wrong run capacitor installed...........Regards, Rod.