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10K views 18 replies 7 participants last post by  paulnwa 
#1 · (Edited by Moderator)
One of my most favorite power tools in my shop is my Performax (Jet) 16-32 drum sander. I use it on almost every project. However, for the last 15 years or so that I have owned it, this tool has frequently frustrated me because the motor circuit breaker frequently trips while sanding.

After investigating possible solutions to this problem, I decided to add an AC Ammeter to allow monitoring of the motor current while sanding. I was able to add this accessory without making any permanent modifications to the sander or motor circuit. In addition, the original 15 Ampere circuit breaker still provides circuit protection.

Addition of this meter allows me to monitor the motor current and adjust the conveyor speed control to keep the motor current under the 15 Ampere level, preventing the circuit breaker from tripping. I am amazed at how easy it has become to eliminate that vexing circuit breaker tripping problem! This change has greatly enhanced my enjoyment and appreciation of this wonderful tool.

A discussion of this problem and my solution, with pictures, is found here:

"http://lumberjocks.com/paulnwa/blog/39600"
 
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#2 ·
What kind of ammeter did you use?
It's good to be able to troubleshooot a problem.
In high school many, many, many years ago I worked in a TV/radio repair shop and I always got a "kick" solving the problem. These were still the day of the vacumm tubes!
 
#4 ·
another great enhancement, paul. i'm looking at applying this to items in my home and shop. if i understand how the above linked item works, one of the load wires passes through the donut, which senses current and activates the display. but what is the 2 screw "terminal block" used for? is that where the tail between the receptacle and the plug (looking at your wiring diagram) provide power to the meter? any chance for a view of the innards of your sander accessory to better explain the techniques employed in functionalizing this very handy item?
 
#5 · (Edited by Moderator)
Hi Toolie-

The terminal block is for the AC input to power the meter. Since the meter only requires very little input current, I attached a smaller diameter wire to each of the two power terminals of the receptacle, where the main line cord terminals attach, and ran them to that green terminal strip. Those are the two wires shown in the diagram that go into the end of the meter. No, I don't have a pic of the inside of the meter box-probably wouldn't be able to see much anyway.

Hope this helps,
 
#7 ·
Hi Dick,

Yes, I can see how you solved this "problem" by removing the circuit breaker and replaced it with a jumper wire.

Even though you can monitor the motor current with your clamp-on ammeter over the jumper wire, you inadvertently removed the motor protection. In the unlikely event that there is a short or other electrical malfunction, you are now relying on your panel circuit breaker, which I suspect is at least a 20A breaker, to protect the motor. If this is the case, you would have subjected your motor to an overcurrent condition beyond its design limits, which could cause permanent damage, and worse yet perhaps cause a fire.

I would highly recommend that you reinstall the original breaker in such a way that you can still use your clamp-on ammeter to monitor the motor current. That shouldn't be too difficult. Then you will still have the motor protection and be able to monitor the motor current to keep it under the maximum 15A rating.
 
#9 ·
Paul: I took a chance and tried your idea with the digital volt ammeter and current sensing coil filled the wiring diagram and unfortunately the second I plugged it all in I blew the meter, fried it,!
Willing to try again any suggestion because right now the sander runs for maybe 30 seconds than the breaker pops
HELP!!!
 
#11 ·
Sorry to hear about your mishap with the meter. With out seeing how you had it wired up, it is difficult to troubleshoot the problem. However, I suspect you had the coil and voltage input leads somehow reversed.

If you are going to try it again, please feel free to send me or post a picture of your wiring set up before you plug it in.

Your quick tripping of the breaker could be caused by trying to take off too much material in each pass. Try setting up the sander to just kiss the workpiece and then advance the drum not more than 1/8 turn and see if it trips. It is also possible that the belt is dull, overloading the motor. Also, you might try slowing the conveyor down to about 60%.
 
#12 ·
I had a grizzly drum sander that was giving me lots of problems with tripping the breaker and also the internal breaker.

I was about to call Grizzly but then I wanted to wait to see something else that might be causing it. That same week, I was having new wiring run to my shop as the main line in was excessively small. Then I had new wiring and sockets ran throughout the shop.

First thing I tested was the sander and never had the problem again unless I tried to take too much off at one time and then, it was only tripping a breaker after the motor really would get bogged down.

It sounds exactly like you have the same problem I've been having.
This was the only tool that gave me that problem, everything else ran fine.
 
#13 ·
Sorry to hear about your mishap with the meter. With out seeing how you had it wired up, it is difficult to troubleshoot the problem. However, I suspect you had the coil and voltage input leads somehow reversed.

If you are going to try it again, please feel free to send me or post a picture of your wiring set up before you plug it in.

Your quick tripping of the breaker could be caused by trying to take off too much material in each pass. Try setting up the sander to just kiss the workpiece and then advance the drum not more than 1/8 turn and see if it trips. It is also possible that the belt is dull, overloading the motor. Also, you might try slowing the conveyor down to about 60%.

- Paul Stoops
Paul:
Thanks for the response: Before I go and buy another set-up first let me try and send you a few pictures of what I did and if you could look at it and advise, I'll send them out tomorrow.
The sander popped the breaker after 30 seconds or so no wood was running thru, just running the motor.
I waited a long time to get this sander I hate to have to give it up.

Thank you
 
#14 ·
Sorry to hear about your mishap with the meter. With out seeing how you had it wired up, it is difficult to troubleshoot the problem. However, I suspect you had the coil and voltage input leads somehow reversed.

If you are going to try it again, please feel free to send me or post a picture of your wiring set up before you plug it in.

Your quick tripping of the breaker could be caused by trying to take off too much material in each pass. Try setting up the sander to just kiss the workpiece and then advance the drum not more than 1/8 turn and see if it trips. It is also possible that the belt is dull, overloading the motor. Also, you might try slowing the conveyor down to about 60%.

- Paul Stoops

Paul:
Thanks for the response: Before I go and buy another set-up first let me try and send you a few pictures of what I did and if you could look at it and advise, I ll send them out tomorrow.
The sander popped the breaker after 30 seconds or so no wood was running thru, just running the motor.
I waited a long time to get this sander I hate to have to give it up.

Thank you

Paul:
Okay attached are the photos I took last night of the way I did the wiring.
Hope the photos help.
A
Passive circuit component Circuit component Hardware programmer Electronic component Electronic engineering


A
Passive circuit component Circuit component Hardware programmer Electrical wiring Electronic engineering


Passive circuit component Circuit component Hardware programmer Electronic component Electronic engineering


Any feed back is appreciated.
Thanks again

- Wantaghwoody
 

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#15 ·
Hi,

Just looking at your photos, I don't see anything obvious about your wiring that would have caused the meter to fail.

So, that leads us to some more questions. Is this a Jet/Performax 16-32? Did you buy it new or used? Is it still under warranty? Are you running it on 120VAC or 240VAC? Is the breaker on the sander tripping, or the panel breaker? What size is your panel breaker? Are there any other tools or appliances on this circuit? Are you using an extension cord? The fact that the motor running without any sanding load trips the breaker indicates that either the motor or something else on the circuit is causing the problem. Please answer the questions and we'll see if your answers ring any bells.
 
#16 ·
Hi,

Just looking at your photos, I don t see anything obvious about your wiring that would have caused the meter to fail.

So, that leads us to some more questions. Is this a Jet/Performax 16-32? Did you buy it new or used? Is it still under warranty? Are you running it on 120VAC or 240VAC? Is the breaker on the sander tripping, or the panel breaker? What size is your panel breaker? Are there any other tools or appliances on this circuit? Are you using an extension cord? The fact that the motor running without any sanding load trips the breaker indicates that either the motor or something else on the circuit is causing the problem. Please answer the questions and we ll see if your answers ring any bells.

- Paul Stoops
Paul:
It is the Jet/Performax 16/32
Bought it used NO warranty
Running it on 120V, the sander breaker is tripping not the 15 amp panel breaker. No other machines in my shop pop the breakers.
I plugged it into an extension cord, but I believe the same thing happens when I plug into the wall outlet.
Maybe I need to have an electrician or electric motor shop look at this?
What do you think!!!
 
#17 ·
I would eliminate the extension cord and plug it into your wall outlet directly, just to take one variable out of the equation.
Do you have or have access to a clamp on AC volt/ammeter? Harbor Freight has a couple of them at reasonable prices. To use one, clamp it around ONE of the two incoming AC power leads. You could probably disconnect your defective panel meter and use the cord/outlet as a short extension cord-that would give you access to allow you to put the clamp-on ammeter around one of the incoming leads. This would allow you to measure the motor current without sanding and before the breaker trips. Just be careful working around the live 120VAC wiring and exposed terminals!

Other than that, contacting an electrician would be a good idea. He could make the necessary measurements and probably easily troubleshoot your problem in person. He should be able to isolate the source of your problem-whether it is within your shop circuitry, the built-in breaker, or the motor. Might be money well spent.
 
#18 ·
I would eliminate the extension cord and plug it into your wall outlet directly, just to take one variable out of the equation.
Do you have or have access to a clamp on AC volt/ammeter? Harbor Freight has a couple of them at reasonable prices. To use one, clamp it around ONE of the two incoming AC power leads. You could probably disconnect your defective panel meter and use the cord/outlet as a short extension cord-that would give you access to allow you to put the clamp-on ammeter around one of the incoming leads. This would allow you to measure the motor current without sanding and before the breaker trips. Just be careful working around the live 120VAC wiring and exposed terminals!

Other than that, contacting an electrician would be a good idea. He could make the necessary measurements and probably easily troubleshoot your problem in person. He should be able to isolate the source of your problem-whether it is within your shop circuitry, the built-in breaker, or the motor. Might be money well spent.

- Paul Stoops
Paul:
great suggestions, my buddy is an electrician, I didn't want to get him involved but now I probably should.
Will keep you posted

Frank
 
#19 · (Edited by Moderator)
Hi Frank,

Glad to hear you are getting an electrician to come and help you out. That is the right way to do it.

If you decide to go ahead and replace your meter setup, I would hook it up and test it three ways before plugging your sander into it. 1) Assemble your meter/receptacle setup and just plug it into the wall with nothing plugged into the receptacle-that will give you a voltage reading and a zero current reading. 2) Plug a low current device like a table lamp or trouble lamp into the socket and see what the meter reads-should be line voltage and probably 0.5 - 1 amperes current reading. 3) Plug another tool like a drill press, corded hand drill, etc. into the receptacle and check the readings. If all looks good, plug in the sander motor and check the readings.

Hope your electrician friend can fix your problem. Keep us posted. Your testing and resolution to your problem will no doubt help other folks who visit this forum.
 
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