Shopsmith Forums

Posted: **Wed Mar 09, 2022 12:19 pm**

Re 'power' meters. Only likely if a thermocouplemeter

Posted: **Wed Mar 09, 2022 1:31 pm**

This machine is probably using a motor similar to one in a 2HP router. Gearing it down to saw speeds is going to help provide torque but it is not a synchronous induction motor and will steadily drop in speed under load. It might cross cut a heavy 12" board reasonably well but long ripping cuts would bog it down. I'm not at all sure what the current draw is on those motors as they slow down under load.

Posted: **Wed Mar 09, 2022 7:03 pm**

Is this the manual for your machine, Powr-Kraft TPC-2610B? It has the 20,000RPM aux spindle.

http://vintagemachinery.org/pubs/657/6025.pdf

Posted: **Wed Mar 09, 2022 8:33 pm**

edma194 wrote: Wed Mar 09, 2022 7:03 pm Is this the manual for your machine, Powr-Kraft TPC-2610B? It has the 20,000RPM aux spindle.

http://vintagemachinery.org/pubs/657/6025.pdf

Yes, that is the manual for my RAS.
I did a test to see what the amps were under load. I crosscut a 4x4,all in one pass,( yes, this saw can cut thru a 4x4 in one cut), and it was only about 7 amps. The blade would slow a bit ; I slowed cut as needed.

Posted: **Wed Mar 09, 2022 8:45 pm**

DLB wrote: Wed Mar 09, 2022 11:57 am
JPG wrote: Wed Mar 09, 2022 9:55 am Universal motor marketers like to tout 'developed' horsepower.

Sorta like "peak' power.

Induction motors 'deliver' horsepower.
I love/hate where this is going. At 115 V and 13 Amps, electrical power in watts for AC is theoretically between 0 and 1495 Watts. If those VA numbers are valid for DC, it is exactly 1495 W. So at ~100% efficiency and a power factor of 1, neither possible for AC, that would be converted to 1495 mechanical watts aka 2.00 HP delivered. If real efficiency and PF are 0.8 (a guess) you're still well over 1-1/8HP delivered, a useful standard for this forum.

Anyone know if those cheap plug-in power meters actually measure electrical watts, as opposed to volt-amps, and will they work on a motor (start current) and/or non-sinusoidal (PowerPro) load?

Since real power is not known, shouldn't we sort of expect a stationary saw with a 13 Amp motor to rip a 2X assuming a sharp rip- or combo- blade and creation of a reasonable kerf? Not as well as a 2 HP induction motor, but kind of as a minimum capability. Therefore perhaps not drawing 13 Amps at full load. I'm back to brush/commutator as a logical starting point for any brushed motor.

- David

DLB, I only follow about 1/2 of what your saying but that's ok. This is what's so good about this forum. I've learned more about the intricacies of electricity following this forum for the last 5 years than my 1st 65 years.

Thanks for all the input.

Posted: **Wed Mar 09, 2022 8:54 pm**

Here is a link to a post of someone restoring this RAS. There is a pic of the motor case opened up showing the motor and geartrain if anyone is interested.

https://www.lumberjocks.com/images/header-bg.png

Posted: **Wed Mar 09, 2022 11:07 pm**

I use one similar to this on my test bench , I see no reason why it couldn't be permanently mounted in some way on the SS or RAS . JMO

https://www.amazon.com/DROK-Frequency-E ... 056&sr=8-6

Posted: **Wed Mar 09, 2022 11:25 pm**

are you sure it is wired right for 110 ? If I recall there are wiring instruction inside some motors that will allow voltage conversions / speed changes , can you find a manual ? if so remove the electrical cover and check for alterations ?
a 3/4 hp motor should be more than enough to cut a pine 2x4 ? .
I would have to look but my 15 amp circular saw cant be too much more than that ?

----------------------------
So for a 2 HP motor it will be 1500 watts or 1.5 KW. An easy way to convert HP (horse power) to Watts is by multiplying by using 745.7W/HP as a conversion factor; so a 2HP motor produces 1,491.4W of power (1.4914kW).

How many watts does a 2 HP motors have? - Quorahttps://www.quora.com › How-many-watts-does-a-2-HP-...
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UNDERSTANDING WATTAGE & AMPERAGE
https://midwestconstructionrentals.com/ ... d-amperage

Posted: **Thu Mar 10, 2022 12:34 am**

Hobbyman2, I use a kill-a-watt meter that plugs into 110v outlet, confirmed with an amprobe.
Motor tag doesn't say anything aboout 220v, only AC/DC 13 amps.
I do have the manual.

Posted: **Thu Mar 10, 2022 8:10 am**

lahola1 wrote: Wed Mar 09, 2022 8:54 pm Here is a link to a post of someone restoring this RAS. There is a pic of the motor case opened up showing the motor and geartrain if anyone is interested.

https://www.lumberjocks.com/images/header-bg.png

I'm interested, but this link doesn't work.

- David

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