herchenx
Cave Dweller
Member since January 2012
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Post by herchenx on Mar 25, 2012 22:47:24 GMT -5
Well my new old saw just went Tango Uniform on me. I went into the garage to find it full of foul smoke. The blade was a few inches into some teepee and not bound at all, but smoke was coming of the motor. Here is the best pic I could get of the toasty motor: Here is a motor my wife's grandfather gave me as a spare for an air compressor he gave me before he passed away (a great man, I might add) I know very little about motors. Can I do a swap? The old motor actually was newer according to the seller (bought the used saw about 2 weeks ago) so I am worried about overloading the new one. I guess I also need to factor in rpm's for the saw and if the pulley on the old saw will even fit the new saw. I know for motor guys this is no big deal but I feel pretty lost. Could the old motor be fixed and is it worth it? Yeah, lost here UPDATE********** Well I bought a $4.95 pulley from Grainger and put it on the larger, faster motor, drilled some new holes in the motor mount (plate) so the new motor would fit, wired everything back up and fired it up. Here is a pic: Everything runs great but I only ran it for a minute because now I have a question about lubrication. The motor seems to be in great shape, and it is smooth and quiet, but it says to lubricate it with 30 drops of SAE10 automotive oil. Then it has some info on how frequently to re-oil based on how much use it is getting. Guess I'm hitting Grainger tomorrow for some oil. The only place that I see that looks like it would accept oil is on the pulley side of the motor directly above the shaft. Is that the only place I need to drip oil? Thanks again all for all the help. I will keep you posted.
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Post by jakesrocks on Mar 25, 2012 22:58:55 GMT -5
Your spare motor spins at twice the speed of the one that burned up. You'll have to do serious pulley changes on the motor and blade arbor to slow your blade down. Both the Diamond Pacific and Covington catalogs have pulley charts that will give you the correct sizes to use. Measure the diameter of the shaft on both motors. If they're the same, you may be able to use your motor pulley, and get a larger pulley for your blade arbor. Measure the diameter off both pulleys and post them here. I and other members have the pulley charts. The sizes of your pulleys will tell us the RPM's your blade arbor is supposed to spin. From that, we can help you with the sizes you'll need with your spare motor. Since you're in Colorado and I'm practically next door in South Dakota, I may have the right pulleys that I can send you.
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Post by Rockoonz on Mar 25, 2012 23:18:23 GMT -5
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Post by jakesrocks on Mar 25, 2012 23:20:28 GMT -5
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Post by johnjsgems on Mar 25, 2012 23:33:58 GMT -5
You don't say what size saw but 1/4 hp is pretty small. I think the 3/4 hp will be 5/8" shaft and the 1/4 is 1/2". You would have to give us the blade size but typically if saw pulley is twice the motor pulley speed will be 1/2. There was a recent post in the saw section about doing it and motors not lasting long. Different size blades have different recommended speeds.
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herchenx
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Member since January 2012
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Post by herchenx on Mar 25, 2012 23:40:53 GMT -5
So, to reiterate - I can say with confidence that the now-fried motor is newer than the saw, but I don't know if whoever replaced it knew if it was the correct one for the application or not.
Here is what I know of the old saw: nothing except a sticker on the front that is badly worn that says "[undecipherable letter] and M Slab and Trim Saw - Roy's Rock Shop - 4978 river road N - Salem Oregon"
It is a 12" saw
the belt is exactly 1/2" wide on the pulleys.
The top pulley - on the saw - is 3.5" outer diameter
The bottom pulley - on the smoky motor is 3" outer diameter.
The RPM on the fricasseed motor is listed as 1725, hp is 1/4, 115 volts, 5.4 amps, 60hz, split phase dayton motor.
the motor shaft of the blackened (cajun-style) motor is 0.485"
none of these specs match the new motor so I am thinking that is out of the question.
NOW, the saw blade and arbor (and pulley) spins freely, but the motor is frozen like a popsicle.
What else can I let you know?
How do I even know if the motor is the right one for this application?
Thanks a TON all.
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herchenx
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Member since January 2012
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Post by herchenx on Mar 25, 2012 23:44:40 GMT -5
yeah I looked at the RPM app, but I don't know what my desired RPM would be to calculate that. This thing didn't come with any paperwork at all. It cuts great though!
when the motor is not burned up, that is.
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Post by jakesrocks on Mar 25, 2012 23:48:41 GMT -5
For a 12" saw, check electrical repair shops for a used 1/2 HP, 1725 RPM motor. Even a 1/3 HP motor would probably work. You'll be able to use your existing pulleys and belt.
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herchenx
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Member since January 2012
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Post by herchenx on Mar 25, 2012 23:51:30 GMT -5
thanks jakesrocks. is a fried motor something you can trade in or have rebuilt? In other words does that give me any possible trade-in-value or is it trash?
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herchenx
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Member since January 2012
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Post by herchenx on Mar 26, 2012 0:02:12 GMT -5
what about phase? What do these saws do best with? (yep, complete know-nothing here)
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jspencer
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Member since March 2011
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Post by jspencer on Mar 26, 2012 0:08:36 GMT -5
No trade in value on them. But you have a weight for a trotline now. I`d get at least a 1/2 hp myself. My 14" has a 3/4 hp on it.
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herchenx
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Post by herchenx on Mar 26, 2012 0:16:00 GMT -5
cool, i'm trying to track down a 1/2 HP 1725 RPM.
What about split phase / capacitor / psc (i only very vaguely know anything about these things)
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herchenx
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Post by herchenx on Mar 26, 2012 0:20:07 GMT -5
Lee I am wary of HFT, although I do buy smaller things from them. Have you used that motor?
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Post by johnjsgems on Mar 26, 2012 7:39:50 GMT -5
I would use a 1/2 hp capacitor start motor. They have more starting torque so more heavy duty than a PSC motor. Covington lists their 1/2 hp capacitor start at $265. If you get the HF motor buy any warranty they offer. Covington uses a 1/2 hp capacitor start on their 12" as does BD on their 14". I wouldn't use anything smaller.
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LarryS
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SoCal desert rats
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Post by LarryS on Mar 26, 2012 7:54:01 GMT -5
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Post by johnjsgems on Mar 26, 2012 8:26:25 GMT -5
If you buy a dual voltage motor they usually come wired for the higher voltage. Wiring for lower voltage is usually very simple and motor will have diagram showing which wire goes where.
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herchenx
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Post by herchenx on Mar 26, 2012 9:13:30 GMT -5
Thanks all. Yeah that Westinghouse in the OP had the wiring info for either voltage on the side.
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Post by deb193redux on Mar 26, 2012 10:21:08 GMT -5
My Grizzly motor is working fine on my cabbing arbor. I aagree that you want 1/2 (or 1/3) hp on a 12" - 1/4hp was too weak.
Since most lapidary blades assume the standard 1725RPM for lapidary, it might be best to just get a motor with that RPM. But, also consider the pulleys you have now. Unless they are the same size, the RPM is being asjusted up ro down. SO figure out if the shaft pulley will even fit on the new motor, then consider if it is the same size at the arbor pulley. If not, replace the motor pulley too.
Having said all that. You can overdrive the newer blades a bit. You might want a motor pulley slightly LARGER than the arbor pulley to give you maybe 2000 RPM or such. Not sure what is possible with standard pulley sizes.
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Deleted
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Post by Deleted on Mar 26, 2012 11:01:24 GMT -5
My two cents. I would use the old motor that you have and get the different pulleys to get the correct blade speed. Pulleys are cheap and you can buy them at most any hardware. I have a 3/4 horse that a friend gave me to use on my 12 inch saw. Nothing slows it down or stops it and if something locks up the blade it would either pop the breaker of burn through the belt which would be a cheap fix. Over powered is way better than under powered and if you end up with a little more speed the thin blades will run smoother. Speed helps stabilize thin blades. My tile saw runs at 3400. I would not run a 12 inch at that speed but like someone else said 2000 or 2200 will not be a problem.
I bought four really old motors (they have bushings so I have to keep them oiled) at a garage sale and one of them has been powering my polisher/trim saw for over a year with no problems. I paid $20 for all of them. Jim
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herchenx
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Post by herchenx on Mar 26, 2012 11:47:59 GMT -5
Jim - yeah that may be the way to go, I need to do a little math to figure out how small:large the pulleys need to be to get the same RPMs I am now. I'd love to not have to buy a new motor.
I can't see a reason why an overpowered motor, properly reduced for speed, would be a bad thing.
I used the RPM calculator that jakesrocks pointed me to, my blade is currently spinning at 1478.57 RPM.
Flipping that around to see how to get that RPM out of a 3450RPM drive with the 3.5" arbor pulley it looks like I need a 1.5" pulley for a 0.624" motor shaft.
SWEET - thanks Jim and all.
jakesrocks I am hitting you up for the pulley!
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