weak MKVII motor

[RFGuy]

Yes, and how much transmission loss is in the SS? That's the question. I could turn the SS speed down to get more torque but my experience from the other day I think the blade would be turning pretty slow. So I would say that if the amp ratings are correct , then there is considerable transmission loss in the SS but if the HP rating is correct and you say there is 50% more power in the ridgid, then not so much transmission loss in the SS.

Yeah, without a proper torque and power curve across the speed range, we don't know how the Mark V responds. I have seen some guesses on the forum in the past, but I don't think we have any actual data to rely on...

[reible]

Construction lumber is really hard to rip. There are the visible twists, warps and often all at the same time. Then when you start cutting the internal stresses start coming into play. I've seen a 2 x 4 that I ripped do a 1/4 turn after the cut.

So to start with a wide kerf rip blade helps. Making sure the fence and blade are aligned is needed. You need some sort of splitter behind the blade, the blade guard does this for you. Turning the speed down helps, as does lowering the feed rate. Examine the wood before sawing, not all of it should be tried.

Now the blade stoppage has all the earmarks of the belt slipping. If that is the case then it a pretty simple fix to adjust it. You still need to do all the above but at least no blade stopping.

Ed

[DLB]

JPG wrote:"I think stalling the motor will cause cb to trip"
I guess I would agree with this, so now I'm leaning towards you guys are saying about belts slipping. With my hearing aids turned off and hearing protection on what I was hearing could be belt slipping instead of motor stalling

RF GUY, I took the cover off and smelled the ploy v belt. Could only detect a faint rubber smell; not nesessarly burnt rubber.

Now your 2nd comment is getting to my 2nd question; mechanical power loss and apples and apples.
Which is more accurate; amp rating (13a vs 14a for ridgid) or HP rating (1 1/8 vs 1 1/2).
Yes, and how much transmission loss is in the SS? That's the question. I could turn the SS speed down to get more torque but my experience from the other day I think the blade would be turning pretty slow. So I would say that if the amp ratings are correct , then there is considerable transmission loss in the SS but if the HP rating is correct and you say there is 50% more power in the ridgid, then not so much transmission loss in the SS.

You mentioned in an earlier post using speed "O" on the MkV. That is already very slow for this operation, 2800 RPM nominally. I'm no blade expert but 10" TS blades are generally designed for around 3450 RPM. I would try faster first.

I have successfully, though sometimes not, ripped construction grade 2X lumber even on a 3/4HP (9 Amp) older Mark. Sometimes with a combination blade. I imagine a lot of folks have done so. To the other issues with this grade of lumber, I would add moisture content. For sure, the lumber varies a lot and can cause problems.

Transmission loss increases with speed. IMO, there is little loss below 3500 RPM in the SS Headstock. But without a doubt, more belts and more bearings mean more loss compared to simpler designs like a dedicated saw. I'm basing my opinion here primarily on measuring input current (Amps) on both the conventional and PowerPro versions. That's not a perfect method, but it is informative.

- David

[RFGuy]

You mentioned in an earlier post using speed "O" on the MkV. That is already very slow for this operation, 2800 RPM nominally. I'm no blade expert but 10" TS blades are generally designed for around 3450 RPM. I would try faster first.

- David

Really? "O" is slow for tablesaw mode? I mean I know that "O" is the bottom of the range marked "Saw-Joint", but I doubt I ever run my saw much higher than "Q" which is kind of middle of that range. I guess he could try running it faster, but wouldn't we expect lower torque there? Kind of hard to know without published power & torque curves.

Of course, depending on belt geometry, perhaps his actual speed is lower than nominal so trying faster might be a good idea.

[DLB]

You mentioned in an earlier post using speed "O" on the MkV. That is already very slow for this operation, 2800 RPM nominally. I'm no blade expert but 10" TS blades are generally designed for around 3450 RPM. I would try faster first.

- David

Really? "O" is slow for tablesaw mode? I mean I know that "O" is the bottom of the range marked "Saw-Joint", but I doubt I ever run my saw much higher than "Q" which is kind of middle of that range. I guess he could try running it faster, but wouldn't we expect lower torque there? Kind of hard to know without published power & torque curves.

Of course, depending on belt geometry, perhaps his actual speed is lower than nominal so trying faster might be a good idea.

Fair enough, I'm confused by conflicting resources. I should have said I've never tried cutting it that slow. The SS laminated chart that happened to be on my desk said 3500 for heavy ripping in both hard and soft woods. That matches the PowerPro built-in look-up table. But a version of PTWFE says 2800 in hardwood and 3000 in softwood. On conventional headstocks I'm usually close to "R" (3500) and don't recall ever using slower than "Q" (3250).

I agree we would get lower torque at higher speed on the conventional headstock. I would still try faster than "O" because I know it has routinely worked for me.

- David

[JPG]

I bet my 9" rip blade(non-carbide) will Work on the MVII with minimal issues.

[lahola1]

"]You mentioned in an earlier post using speed "O" on the MkV."
I did start with higher speed but then moved to "O" cause the chart said for hardwood; more torque but there wasn't much change in speed or cutting ability.

Anyway, I've decided to get a 24T rip blade and see how that works .

Before I end this thread I would like one of you electrical guys to answer this question.
If the motor windings are burnt or scorched, can they be repaired before it fails completely?
Is that something a local repair shop does (or that guy on ebay that says he will repair SS motors for $89.00)?

Thanks for all the input.

[RFGuy]

If the motor windings are burnt or scorched, can they be repaired before it fails completely?

So, are the motor windings burnt/scorched on your motor? If so, it is possible that a winding can be partially short circuited which could affect its performance. Kind of rare, but it can happen.

[lahola1]

RF Guy, No, I haven't checked anything yet. I'm just asking the question if they ( if any motors windings) are burnt but not shorted/open, can it be repaired , if so , by who? This specific question is for me to learn more about electric motors in general, not nesessarily my SS motor.

[chapmanruss]

lahola1,

You asked again,

Before I end this thread I would like one of you electrical guys to answer this question.
If the motor windings are burnt or scorched, can they be repaired before it fails completely?

I believe that is a question that may be best answered by a repair shop looking at your motor. They would be best equipped to asses your motors condition and what may or may not need to be done at this time.