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.