Kapex heat and smell =(fixed)=

[Timtool]

while using my 2007 Kapex today on rough and tough cuts on rather thick pine beams, it started smelling burned, i thought it was the neighbours burning plastic again (which they actually were) and before i realised it was the Kapex, it suddenly slowed down to about 50% speed so i stopped.
The motor housing was warmer than usual, i used the compressor to blow out the little dust and cool it down.
I started it up again, it turned at full speed but the smell was back, i opened the housing and took out the brushes which aren't worn out at all.

My dad was welding a bit further all that time on the same circuit and it made the lights dim, can this cause problems to a tool like the kapex?

I called Festool but the technicians had all gone home already, so the only advice i got was to bring it in to my dealer so they can pick it up and check it out.

Anybody got any ideas on what could be wrong? could it be out of oil? It's out of warranty so if i can fix it myself i would rather not send it in and be without for at least a week.
i recently replaced the circuit board on it as well.

 

[PeterK]

Sure sounds like the voltage dropped from having too much load on the circuit. Low voltage causes the tool to draw higher current which can easily overheat a motor. The saw slowed down to protect itself I would assume as the TS saws do that. Sure sounds like the circuit is NOT protected by the correct size breaker as it should have tripped if the current was running high from having too many items running. You need to look closely at the wire size feeding the outlets and get the correct breaker on it.

 

[Timtool]

Thanks Peter,
Thats what i suspected, without having the technical knowledge to explain it.
I told the festool guy i was gonna wait till tomorrow and see then if it's back to normal, the slowing down when overheating is common to many festool tools.
i think many if not all have this feature.
I just hope theres no permanent damage.

 

[Steve R]

Sure sounds like the voltage dropped from having too much load on the circuit. Low voltage causes the tool to draw higher current which can easily overheat a motor. The saw slowed down to protect itself I would assume as the TS saws do that. Sure sounds like the circuit is NOT protected by the correct size breaker as it should have tripped if the current was running high from having too many items running. You need to look closely at the wire size feeding the outlets and get the correct breaker on it.

Timtool,

I agree with PeterK, sounds like voltage drop....  it is hard to believe that a kapex, CT and Welder will all work on one circuit. [eek]

Just wondering is this a 20 amp circuit?

Is this in a shop that you have worked before... or are you at new location?

Any extension cords that aren't 10 gauge?  

I won't run a CT and Kapex or any TS saw on one 15 amp. If at all possiable I will put the kapex and the CT on individual 20 amps circuits.  It just gets to be to much. But if you weren't tripping a circuit then  ???. voltage drop.... Got a meter you can check the voltage with?

Cheers,
Steve

 

[PeterK]

I really doubt you caused any real damage. When the insulation or varnish on the motor gets hot it will definitely create an odor. Done this many times with large motors! Would think at worst you may have shortened the life somewhat.

 

[Rick Christopherson]

Sure sounds like the voltage dropped from having too much load on the circuit. Low voltage causes the tool to draw higher current which can easily overheat a motor. The saw slowed down to protect itself I would assume as the TS saws do that. Sure sounds like the circuit is NOT protected by the correct size breaker as it should have tripped if the current was running high from having too many items running. You need to look closely at the wire size feeding the outlets and get the correct breaker on it.

This is true for induction motors, but is not true for universal motors, such as Kapex. For universal motors, controlling the speed is actually accomplished by reducing the voltage, so having a voltage drop does not pose any issue with this type of motor. (The speed controller uses Pulse-Width Modulation for speed control, but that is simply for efficiency, not effectivity.)

If the OP was observing a burnt odor, it is likely that the saw was being overworked for the task and speed. When this happens, either allow the motor to cool naturally, or run the motor at full speed with no load to allow the cooling fan to clear the built-up heat. Making brief, high-load cuts can cause a motor to generate significant heat in the windings, but not give the cooling fan sufficient time to clear this built-up heat. The contact points of the brushes to the commutator are probably the source of this extra heat, but it propagates through the rest of the motor through conduction.

 

[VictorL]

I agree with PeterK, sounds like voltage drop....  it is hard to believe that a kapex, CT and Welder will all work on one circuit. [eek]

Just wondering is this a 20 amp circuit?

Is this in a shop that you have worked before... or are you at new location?

Any extension cords that aren't 10 gauge?  

I won't run a CT and Kapex or any TS saw on one 15 amp. If at all possiable I will put the kapex and the CT on individual 20 amps circuits.  It just gets to be to much. But if you weren't tripping a circuit then  ???. voltage drop.... Got a meter you can check the voltage with?

Cheers,
Steve

Steve,

It's Europe. There is 220-240V is normal residential  power, so they do not have our restrictions, extremely thick wires and tons of circuit breakers on one panel.
So welder, saw and vacuum on one circuit is heavy, but not deadly load.

 

[Evergreen]

Same thing just happened to mine about a month ago.  It had all the  symptoms you've mentioned...  Turned out it needed the armature replaced.  I'm not sure why, but it did and I got what seemed like a brand new saw back from Festool.  I went to the place I purchased it from and they had an extra Kapex box to ship it in.  I'd highly recommend doing the same.  Good luck!

 

[Timtool]

It was in my workshop with the kapex and welder on same circuit, the DC is on it's own 380 V circuit.
Anyway it seems to be fine this morning, runs normal with no smell.
Ill wait some time before yelling victory, but it may also be a good idea to have the blade sharpened.
It's been over a year and a half that i had i resharpened  [embarassed] it's just that it cuts so good and i don't want to buy a spare blade for it to use while the other is being sharpened. It's so damn expensive around €150