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Question for PM3520 owners

Caniac

Caniac

Joined
Mar 30, 2005
Messages
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Location
Burlington, NC
Has anybody had this problem before?

I was sanding up a bowl I had picked up to finish from a rough out- red oak, I'm a glutton for punishment- and had the lathe reversed and running at 150 rpm whilst power sanding with my trusty right-angle sander.

After a few minutes of this, I decided there was too much tear-out in one particular area to sand away with the 80-grit gouge, and decided to take a few more light cuts with the bowl gouge.

At first, when changing the speed back to forward (I did turn off the machine first), it wouldn't spin. If I changed back to reverse, spun the wood, then went back to forward, it would finally work (though there seemed to be a little delay before the lathe "woke up" and started spinning).

A light cut, stop to check my progress- then go to restart the lathe, no luck. The thing will spin in reverse just fine, but when I try to go back to forward to cut some more, it just sits there... mocking me. :mad:

So, I go to bed. The next morning, it seems to be working fine. I finished the bowl (a little thinner than I'd like, but an ok form, I guess). Still bugs me why this happened, though. I'd bet my banjo it's a controller issue (the one on the back- not the one standing in front, though that's possible, too... 😉 ).

Anybody else have this happen, or know a fix, should it happen again?

-Jeff
 
My 3520 is about 2yrs and change. During the hot weather this summer I didn't use my lathe for about 2 months. Went out one day to turn and nothing. After I got my breath back I tried the circuit breaker and power cord, nothing. I checked the outlet with my volt meter 110v on both legs, plugged it in, nothing. I'm really starting to feel sick now. It finally occurred to me there may be a reset on that gizmo on the back of the lathe. There was. I pushed it and tried again. This time I heard that sound only the PM makes. I'm not sure what happened to trip the reset but I unplug the lathe now as often as I can remember when I'm finished turning. I run my lathe in both directions at varying speeds with different size/weight objects and haven't experienced any problem like you describe. If it happens again try turning it off and unplug the lathe for a few seconds plug it back in and try again. If it continues to be a problem I'd call the 800 # and see what they think. Please let us know how this turns out. For what it's worth don't even mess with that controller on the back of the machine other than to push the reset. Hope this helps,


Jim
 
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I agree with Jim. It was probably just a temporary glitch in the VFD (variable frequency drive), which I also call a controller. As many know, I have over 2,000 hours on my 3520. Occasionally it has problems. But they are pretty rare.

When I ran the 220, I also installed a standard double pole 20amp switch on the wall right behind the lathe. That switch gets turned off at the end of each turning session or turning day. Sure beats unplugging it when it's not in use for long periods like a week.

I doubt if you could do anything to mess up the controller via the buttons. The settings are password protected. Most of the 3520 factory settings are pretty much ok for just about all turning.
 
Could it be a loose nut on the tool rest?😀

I experienced this once while using the club's 3520. I just walked away for a while to see what the other turners were doing and when I came back about 15 minutes later, it had regained its senses and worked OK.

Most controllers usually have at least some degree of fault monitoring (real or imagined). Who knows what it could have been? Well, actually you could have known provided that you had access to the programming manual for the controller and were software fluent. You can get it to display fault codes that may or may not help you to determine why it shut down. Sometimes, available motor parameters are used to extrapolate operating conditions and make a presumptive guess at things like torque or thermal conditions.

On the other hand, there is probably an ornery behavior algorithm in the controller that operates in conjunction with a random number generator.😉

Bill
 
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A bit anal perhaps but..........

I also have a two pole switch and I unplug after each session (lighting protection.) Also once a month or so I open the door on the head stock and gently use my compessor to blow out any dust from around the switches. Then the controller is subjected to a good vaccuming (all power off and unplugged.) Machine is used quite a bit, not as much as our moderator though, and nary a problem such as you have experienced. 😱 😀
 
The 3520 program manager whom I met at the 2005 Symposium in the tradeshow booth discussed the power switch. He indicated I was lucky it had lasted this long. Jake - I think that is a good tip to blow the dust out of the switch, it could make it last longer and it sure won't hurt.

In the event of a small emergency the 2 pole switch on the wall can be used as a cutoff switch to turn off the lathe. Not as easy as hitting the stop button, but it will cut the power!
 
Thanks all for the replies.

I did in fact call Powermatic tech, who felt that it was likely an overheating issue. Why it would still run in reverse, they couldn't say. He did suggest that, should it happen again, I should call right away and let them walk me through pulling up the error code on the controller.

How that's supposed to help a (mostly) weekend woodturner when their tech support only runs weekday business hours was lost on me... 🙄

I put in another few hours yesterday evening and it ran like a champ. Hopefully it will just end up being one of those aforementioned glitches and won't be bothering me too much in the future.

-Jeff
 
Blowing the dust out is a very good thing to do. The controller electronics are subject to overheating if the airflow is blocked even just a little by dust on the heat sink. And, please don't do like some of the owners of Powermatic 3520's that I know who think that the heat sink is a cool place to store the knockout rod. It won't be so cool for the heat sink as it is blocking some of the ventilation that keeps the driver transistors cool. Why it ran backwards and not forwards may possibly have something to do with a bug in the fault monitoring algorithm.

Bill
 
All I can say is that my 3520 keeps on chugging. It gave me another 3 hours of service tonight. I roughed out the outside and inside of another 18" Box Elder vase. Ah, the fresh smell of mildew is in the air!!! (box elder smell)
 
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