RPM Low notice PowerPro Unit

[EmmettRichards]

I purchased the PowerPro Headstock in 2017 using it for small projects. I had a standalone table saw so I didn't use the Shopsmith for table saw cutting until my standalone unit failed. Now that I'm using my Shopsmith table saw function, the system shuts down when I cut anything greater than 1/2 inch thick. When this happens, I get a "LOW!" message on the PowerPro Headstock, although while the unit is running, the RPMs vary by as much as 50 units. When the unit shuts down, I simply push the run button, and it starts up again. Sometimes I need to do the reset multiple times to finish a simple cut. Do I need to convert my Shopsmith from 110 to 220 to avoid this error?

Emmett Richards

[RFGuy]

Emmett,

This thread (https://www.shopsmith.com/ss_forum/view ... ow#p266679)may have some answers for you. Also, have you seen the troubleshooting document from Shopsmith (see below):

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MARK_7_Troubleshooting.pdf

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[garys]

Since you are running on 120v, one of these will tell you if you have a line voltage problem. And, it will be cheaper and easier than calling that "qualified electrician".
https://www.amazon.com/P3-P4400-Electri ... B00009MDBU

[DLB]

I'll see a "LOW!" very briefly when the PP is just starting to spin up. This is not the same as "LOW VOLTAGE." When mine is running at that speed, 3450 RPM, measured RPM variance is less than +/- 10 RPM. I've never looked at it while actually sawing, I like to keep an eye on the blade, but just by listening I don't think it is varying and definitely not bogging down.

I do not have, and have not seen, a document containing a complete list of PP error messages. This does not seem right to me, I feel like I should have such a document. I don't know the definition of "LOW!" Intuitively, I'm thinking measured RPM are X lower than set RPM. But is that right and what is X?

I don't see 220V helping but that doesn't mean I wouldn't try it. Unless there is something else wrong the PP should have decent power on 110. Tis a mystery to me why the PP does not follow convention (maybe there isn't one?) on plug and adapter type for dual voltage, auto selection, equipment.

As a test to make it work harder, you might try running it at 9500 or 10K and see how it responds. I think the motor/electronics are probably working harder doing nothing at that speed than you are asking them to saw 3/4" stock.

- David

[JPG]

I cannot help but wonder if the reason the 'other' saw has failed is ALSO due to low 'house power'.

[RFGuy]

Don't know if this is of any use, but I found this on Teknatool's website related to their DVR motors (Teknatool makes the PowerPro components for Shopsmith). Perhaps this "LOW!" warning/error message is the same between Teknatool Striatech's DVR offerings and the PowerPro. It might be worth double-checking the connections between the PowerPro components. It could also be a problem with the position sensor, so possibly dust infiltration is causing it?

https://teknatool.freshdesk.com/support ... technology

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[mindpilot]

So if I understand correctly, this problem only occurs during table sawing operations and all other setups work fine? That creates a very curious scenario indeed.

My newly upgrade PP performed fine yesterday ripping a long piece of 2" close-grain pine. (a piece that came from a house built in 1927, so it was pretty hard) I was impressed with how the PP maintained speed and power throughout the cut. There was no lagging or burning, and the sound never changed.

[sehast]

The only reason it would occur in the table saw mode and not in others would be the increased load placed on the motor or maybe the higher RPM used. Try just spinning the blade at varying RPMs without sawing anything to prove this theory.

[DLB]

I have some data and observations, not sure that this can help.

If the definition for "LOW!" provided by RFGuy from teknatool is right, then it may not be telling you anything that you don't already know: that the unit shut down. I suggest taking video of the screen when the fault occurs to go back later and see if there is a fault indication at the time it starts shutting down.

While cross-cutting some cedar 4X4's I set mine up to monitor input amps and RPM. Current at 3450 RPM, blade turning but not cutting, was ~ 3A. While cutting, this increased to ~9A. I tried a high feed rate and it increased to ~10.5A. This was not a through-cut, but was about 3-1/8 deep. To me this would indicate that there is a fair amount of reserve power. I also noted that the RPM variation increased to about +/- 25 RPM while cutting. (In my previous post I had observed +/- 10 not cutting.)

For comparison, with nothing attached to the PP, a speed of 9300 also draws 9 Amps.

- David

[jsburger]

I have some data and observations, not sure that this can help.

If the definition for "LOW!" provided by RFGuy from teknatool is right, then it may not be telling you anything that you don't already know: that the unit shut down. I suggest taking video of the screen when the fault occurs to go back later and see if there is a fault indication at the time it starts shutting down.

While cross-cutting some cedar 4X4's I set mine up to monitor input amps and RPM. Current at 3450 RPM, blade turning but not cutting, was ~ 3A. While cutting, this increased to ~9A. I tried a high feed rate and it increased to ~10.5A. This was not a through-cut, but was about 3-1/8 deep. To me this would indicate that there is a fair amount of reserve power. I also noted that the RPM variation increased to about +/- 25 RPM while cutting. (In my previous post I had observed +/- 10 not cutting.)

For comparison, with nothing attached to the PP, a speed of 9300 also draws 9 Amps.

- David

With no load I would think the RPM's should not change. It you are seeing +- 10RPM's no load that is probably the resolution/tolerance of the RPM sensor. +-25RPM's under heavy load seems to be quite reasonable to me. Even the OP's +-50 RPM's doesn't seem excessive to me. Mine dances around but I have never paid attention how much. It doesn't effect anything. I always chalked it up to sensor resolution. If you have a non contact RPM sensor that uses reflective tape on the spindle it will also bounce around.

The issue here is why the machine is shutting down. When the machine "shuts down" or turned off you always get a LOWVOLTAGE "error" on the screen. That is not a true error condition. If you get a LOWVOLTAGE error with the machine running then that is a problem as addressed in the troubleshooting section of the manual. There is no LOW error in the manual, only LOWVOLTAGE.