Shopsmith Forums

Dusty I totally agree with you. They, the MS wants to promote the Power Pro as the Ultimate Machine in a SS, this is not, in that mode IF it is the normal case in Routeing. If it is a defectives sensor that is an other issue.

As others have mentioned you need to get back to Shopsmith and let them have a chance to help resolve your (and possible our) issue.

In the mean time you might want to turn the speed down to say 9000 or 8500 evey 8000 rpm and see if it will stay running and let you finish what ever routing you still have left to do. Keep in mind the stock shopsmith can be used for routing at a much lower rpm, so if it will stay running at even 8000-8500 rpm it is still much faster then a stock machine.


Yes you will have to feed slower but as it is now you need to shut down every 15 minutes to cool so it might well be faster to feed slower and stay running.

I have not had this happen to mine but I don't use it as my router, nor for that matter did I buy it for that reason. But they are advertising it as a router so it should be able to run for an extended time, not just 15 minutes. I'd hope they can fix the issue quickly.

Another though is to check is to make sure the belts are adjusted, either too loose or to tight can cause a heat build up, and add to the issue. You could also make sure it has air flow around it with a small house hold fan blowing on the headstock. Making sure sun light is not striking it, I use mine outside and just having it in the sun warms it up a lot.

Ed

reible wrote:As others have mentioned you need to get back to Shopsmith and let them have a chance to help resolve your (and possible our) issue.

In the mean time you might want to turn the speed down to say 9000 or 8500 evey 8000 rpm and see if it will stay running and let you finish what ever routing you still have left to do. Keep in mind the stock shopsmith can be used for routing at a much lower rpm, so if it will stay running at even 8000-8500 rpm it is still much faster then a stock machine.


Yes you will have to feed slower but as it is now you need to shut down every 15 minutes to cool so it might well be faster to feed slower and stay running.

I have not had this happen to mine but I don't use it as my router, nor for that matter did I buy it for that reason. But they are advertising it as a router so it should be able to run for an extended time, not just 15 minutes. I'd hope they can fix the issue quickly.

Another though is to check is to make sure the belts are adjusted, either too loose or to tight can cause a heat build up, and add to the issue. You could also make sure it has air flow around it with a small house hold fan blowing on the headstock. Making sure sun light is not striking it, I use mine outside and just having it in the sun warms it up a lot.

Ed

Ed, by Bosh router runs on high speed at 1300RPM it is 2 1/4 HP motor, yes I can slow it down for large diam bits, but a quarter round which I use a lot 1/8" and 1/4" first pass, I find the SS PP unacceptable for that as described here.

ERLover wrote:
Ed, by Bosh router runs on high speed at 1300RPM it is 2 1/4 HP motor, yes I can slow it down for large diam bits, but a quarter round which I use a lot 1/8" and 1/4" first pass, I find the SS PP unacceptable for that as described here.

I know of no router that runs that slow, my guess the number is 20000 plus, typically with a low end of say 8000. I have one router that has a top end of 27000 rpm. Most of mine have a top end in the 21000-23000 rpm.

Best check your manual.

I don't anyone here thinks the Powerpro routing for 15 minutes is acceptable but I want to give the user a few options that might let them get the job done right now and then get the "issue" resolved in the long term. Nothing is going to happen at shopsmith over the week end.

Ed

I can answer the "why it overheats" at high speed part. The short answer is "switching losses".

The long-winded answer is that the faster a motor spins, the higher the commutation frequency of the windings. The higher the frequency, the less effective the laminations in the motor iron are at stopping eddy currents. Which means that those eddy currents heat up the iron faster. That is exactly how an induction heater works.

Any DC motor has a speed beyond which it cannot run continuously without overheating, even under no-load conditions. And, of course, this speed depends in part upon how quickly you can conduct heat out of the motor. In rough order of effectiveness, potential cooling measures include passive cooling fins, forced-air fans, and liquid coolant.

And of course, if you add an output load to the motor (such as a heavy routing operation), that requires more motor current. The heat generated by the load current adds directly to the heat generated by the switching losses.

reible wrote:

ERLover wrote:
Ed, by Bosh router runs on high speed at 1300RPM it is 2 1/4 HP motor, yes I can slow it down for large diam bits, but a quarter round which I use a lot 1/8" and 1/4" first pass, I find the SS PP unacceptable for that as described here.

I know of no router that runs that slow, my guess the number is 20000 plus, typically with a low end of say 8000. I have one router that has a top end of 27000 rpm. Most of mine have a top end in the 21000-23000 rpm.

Best check your manual.

I don't anyone here thinks the Powerpro routing for 15 minutes is acceptable but I want to give the user a few options that might let them get the job done right now and then get the "issue" resolved in the long term. Nothing is going to happen at shopsmith over the week end.

Ed

I am sorry, I was going from my goofed up memory, I pulled out the manual, high speed on the Bosh is 25,000RPM
Low speed is 8000RPM

BuckeyeDennis wrote:I can answer the "why it overheats" at high speed part. The short answer is "switching losses".

The long-winded answer is that the faster a motor spins, the higher the commutation frequency of the windings. The higher the frequency, the less effective the laminations in the motor iron are at stopping eddy currents. Which means that those eddy currents heat up the iron faster. That is exactly how an induction heater works.

Any DC motor has a speed beyond which it cannot run continuously without overheating, even under no-load conditions. And, of course, this speed depends in part upon how quickly you can conduct heat out of the motor. In rough order of effectiveness, potential cooling measures include passive cooling fins, forced-air fans, and liquid coolant.

And of course, if you add an output load to the motor (such as a heavy routing operation), that requires more motor current. The heat generated by the load current adds directly to the heat generated by the switching losses.

This is right on..... The frequencies are so high that it comes close to being a short circuit. It is the same problem we have with CPU temps as we started getting into the GHz freqs. I forgot that (I seem to be forgetting a lot of my digital knowledge now that I am out of the business LOL).

I retract my earlier question. Dennis just answered it. I am getting old and unable to keep up with the clock duty cycle ....

With that said, my PP is no where near that sensitive. I have routed board edges for 45 mins to an hour with no stoppage. I have had the PP overheat, but only once or twice. FWIW

http://www.shopsmith.com/shopsmithpower ... nology.htm
Maybe they should have tried 1 hour of routing instead of countless hours of thickness planing.

Skizzity wrote:http://www.shopsmith.com/shopsmithpower ... nology.htm
Maybe they should have tried 1 hour of routing instead of countless hours of thickness planing.

Maybe the PP is/cant handle that speed for any length of time?? If the MS sez it can, then time for them to step up to the plate with it. I dont have one and have a Bosh Router but when doing routering it is not running continuous under load for more then a few minutes at a time.

DVR motors have no rotor windings to fail and overheat where conventional AC and DC motors do and DVR consistently run 80% more efficient so where's the heat generation actually coming from?

Everett