Whatcha Sawin' 2025 ??

[Magicman]

I returned to a many times repeat customer this morning:


15 logs but about half were "too far gone".   Very good help.  


SYP is some purdy stuff!!


964bf of mostly 1X12's with eight 8X8's not shown.  We called it quits when we had to slab too deep to reach the small amount of good wood.  He was happy and so was I.

I think that my next job is hardwood. ??

[Old Greenhorn]

Well, you can check current (amps) with many multimeters, but you have to run the  feed through the meter and change the connections in the meter, meaning you have to disconnect the line and connect the lead to the meter and the other meter connection goes to the terminal. However, most of the cheaper meters we all use do not allow for this. Those more expensive meters that do will have a low limit on the amount of current they will handle before burning up. If you have a nice Fluke meter, it might handle 5 amps or a bit more. Less expensive ones only handle an amp, maybe 5 at best.
 For serious current to run a motor or something you need a clamp on ammeter such as MM showed. Those aren't cheap, but they can tell you an awful lot. They worked by induction and sense the current traveling through the conductor. The ones I used always belonged to my employer because of that cost and troubleshooting was not mt main job. If I blew it up, the boss ordered a new one (I never blew one up). I may have an old one around here somewhere I could use in a pinch.
 This is why I suggested a infrared thermometer earlier, it's a lot cheaper but still lets you detect heat rise in a conductor.

[WV Sawmiller]

You are not going to get an amp reading with a multimeter. 

 
Reading a circuit's amperage is a whole 'nuther ball game.  Here I am reading the voltage with a multimeter and the amperage with an ammeter.

The power feed motor does not operate with a varying voltage but with a varying pulsed voltage controlled by the circuit boards, etc. that Ted referenced to above.

Lynn,

  Thanks for the semi lesson. I now know I need to get an ammeter but where do I need to place it to get a reading and what is normal or excessive amps? The feed motor has 2 wires to it that look to be about 10 gauge wire. Do I need to encircle the wire at the motor or somewhere inside the control panel? What would be acceptable and what would be excessive amps? 

[Magicman]

As I mentioned earlier, the power feed motor does not operate with a varying voltage but with a varying pulse voltage.  All of the tests that I have done with the techs at Indy have been with a test lamp not an ammeter.  I have never had a power feed problem.

Howard, I am not knocking you for anything that you did or did not do.  I still feel that your ongoing problem has not been with the components that failed but with a dirty connection that was causing the components to fail.  Put a new component in and it will fail just like the previous one did.  That center wire could have been that dirty connection.  

As Tom mentioned, "tight is not good enough".  It has to be clean and tight.  I know that you eliminated one problem, I just hope that it was the problem. 

[SawyerTed]

If I'm not mistaken, the feed motor is a 1/2 hp 12 volt motor.   Full Load Amperage would be between 35 and 40 amps.  It should not operate at full load very often.  Full load would be nearly or completely stalled.  So amperage drawn should be considerably less. 

Not every clamp on meter like Lynn pictured measures DC amperage.   When looking for one, check for that in the specs.  About all measure AC amps.  The clamp on types can measure several hundred amps.  We used to have to measure amps with the meter inline as Tom was indicating.  

There was mention of a bare wire leading to the motor.  That could easily be the source of the high amperage/heating issue.  Intermittent contact to ground might not have been enough to trip the breaker.  

Did you have breaker trips prior to finding the bare wire?  

[WV Sawmiller]

   I found the bare wire while changing the motor and taped up the spot. Yesterday I cut and properly replaced the terminal end. Prior to replacing the motor I was sawing an oversized log and the breaker was tripping constantly then on the smaller log following my feed became too erratic to run. The erratic feed turned out to just be a worn out feed belt as far as I can tell as a new speed controller (Potentiometer) did the same thing but the new belt stopped it.

   My new switch I ordered Thursday from Atlanta came yesterday but I'll try the repaired on till I feel it is not working right. 

   I have replaced and checked the connections and don't know where else to look if it comes back other than feeling for a hot wire somewhere.

[SawyerTed]

Howard, all the clues say you have gotten to the bottom of it.

[Magicman]

There is a shunt that you can use that is wired in series with the circuit.  Your regular multimeter reads the small voltage drop across that shunt which is then converted to amps.

The problem with the circuit in question is that the driver is variable and creating a model for the testing duration could be a challenge.  As I understand it, the current draw for that motor should be fairly constant but the supply voltage is pulsed which varies the speed.  This would be very difficult to test with our normal test gear.  It would probably take an oscilloscope.

Howard, I am hoping that you have isolated your problem with the overheated crimp connection but if not you may have to resort to a thermal heat gun/sensor that someone suggested.

[Dave Shepard]

On my Super, Wood-Mizer told me they use PWM, or pulse width modulation to control motor speed. They basically increase or decrease the amount of time that the motor is grounded, many times per second.

[Magicman]

Exactly.   

Now if there is a bad or compromised connection in that circuit going through the motor, the result will be heat.  That circuit includes both the 12V hot and the pulsed ground.

[SawyerTed]

Won't polarity have to switch for reverse operation?  

[Magicman]

Yes, reverse is reversed polarity and direct with no speed control nor reduction.

At one time Wood-Mizer offered different size sprockets which would speed up the reverse with hardly any affect on the forward operation.  I doubt that they still do.

[SawyerTed]

So a short to ground would only be a short half time?  Only in forward or reverse depending upon which wire was bare.  

[doc henderson]

breakers and fuses are designed for a designated voltage and designated amps.  so, a blown fuse or thrown breaker can be a down and dirty way to say you are pulling too many amps, especially if it is repeated.  and do not think you must have a bunch of bad fuses and bypass it cause you'll burn up other stuff, letting the smoke out of the wires.