Thread: TKS 80 ebs set

I've run my Kapex off my CT 36's remote socket and am still not dead.

The CT's socket is rated at 1800W @ 240V, which would be 7.5A. The DC itself wants a max of 1200W @ 240V which would be 5A, so I guess if both were maxed out they'd want more than the 10A socket.

The Kapex wants 1600W @ 240V which would be 6.66A, so again, I suppose that the saw at max power 6.6A + the DC at max power 5A would exceed a 10A socket but I'm not sure how often that happens? I've never popped any circuit breakers, and no smoke signals have been sent. I've never bogged the saw down, and only cut when the blade is up to full speed. It's like a hot knife through butter.

Never really thought about it as it seems to be pretty common practice. Maybe I'll stick the vac into the 15A socket.

Most 10A power points are wired from a 16A circuit breaker with 2.5mm² wire which is rated at 25A. This enables you to run high current power tools off the CT but if you exceed the 16A or get close to it for any length of time you will trip the breaker.

Because the CT is supplied with a 10A plug (required to enable it to be used anywhere) regulations require there to be a limit on the power that you are allowed to draw.

In the case of the SS ripping timber with the standard blade it would most certainly have been at full load, and maybe even overloaded, so the 2200W of the SS + 1200W of the CT would have been drawing about 15A.

I use my CT with my CMS fitted with the OF2200 and a power feed and the only problem that I have ever had is to blow a fuse in the CMS when I took too big a cut.

Next time I go to Total Tools I will check the ratings on the dust extractors, both Festool and others, and see what is going on. From memory they were all rated around the 1,000 watt capacity, some were less than that. Perhaps things have changed with the newer models?

Festool CT26 and 36 Tech data.png Festool Kapex Tech data.png Festool EBS tech data.png

Interesting Bernmc, very interesting. Not what I remember from looking at the machines on the shop floor. I need to have another look. Thanks for the info.

The discussion so far has centred on the ratings of the various components of the circuitry including the leads.
My ref below gives some clarity to how burn outs can occur.
In this instance my observation made previously that the Thermal overload on the S/S did not protect the machine still stands.
I have registered a query with Festool (UK) on this basis; today being our Celebration day.

The motor in the TKS80 is not an induction motor. It is a brush motor which is not constant speed, as the load increases above its rated power the speed will drop and the power drawn will increase significantly. (well above its 2000W rating)

When I trained as a wireless operator with AWA more than 50 years ago we had this saying that a $5.00 transistor would always fail before the $0.10 fuse that was supposed to protect it. Thermal overload devices are, in general, even slower to react. It's interesting to note that the same type of machine has different ratings in parts of Europe, the UK and finally the USA.

Originally Posted by Bohdan

The motor in the TKS80 is not an induction motor. It is a brush motor which is not constant speed, as the load increases above its rated power the speed will drop and the power drawn will increase significantly. (well above its 2000W rating)

Hi Bohdan,
According to the handbook(P.34) the motor and its electronics are designed to deliver constant speed at wherever the speed is set(1700-3500 rpm).
in my instance about 2600rpm. In this case I don't think speed was a determinant but it was more likely to be acting according to the to the Electro- Physics formula
quoted in the previous reference i.e the voltage drop across the other components in the circuit effectively caused the S/S motor to drawer more current and under voltage to the motor.
To this stage I do not have any details about the thermal overload incorporated in the S/S.

R.
Les.

Hi Old Holly,

Yes I agree (Fuses seconds, Circuit breakers milli - seconds), I have been brushing up on my old RMIT formulae and realised
that we now live in the digital age where sensors and IC's are the goto which leads me back to what type of thermal overload Festool is using?

R.
Les.

I think, Les, that it's the operating environment that restricts the choices for overload protection. Any of the new batteries have regulation for charge, discharge and cell balance built in. Draw too much current or have the voltage drop below a certain figure and the management system shuts the battery (and thus, the tool) down. Things are not so simple or cheap when we run directly from the AC mains. The average AC mains waveform is nothing like "clean". There are spikes, dips, other frequencies (hot water controls) superimposed on the 50Hz and in some areas there is even an internet type signal that enables remote meter reading. And to make it worse we now have grid connected solar doing all sorts of things to what used to be a fairly stable and clean 50Hz sine wave.
Perhaps a battery powered saw is the way to go?

Originally Posted by skeetas

Hi Bohdan,
According to the handbook(P.34) the motor and its electronics are designed to deliver constant speed at wherever the speed is set(1700-3500 rpm).
in my instance about 2600rpm. In this case I don't think speed was a determinant but it was more likely to be acting according to the to the Electro- Physics formula
quoted in the previous reference i.e the voltage drop across the other components in the circuit effectively caused the S/S motor to drawer more current and under voltage to the motor.
To this stage I do not have any details about the thermal overload incorporated in the S/S.

R.
Les.

The speed control on a brush motor is designed to restrict the speed by limiting the power being fed to the motor. This enables a constant speed to be maintained if the motor slows down by feeding more power to it. If the motor is at max speed it then acts as a simple brush motor and if it slows down due to load it then draws lots more power. The voltage being fed to the motor does not need to drop for it to draw much more current.

The thermal cutouts in these cases are designed to measure the windings temperature and if they are exceeded cut the power to the motor until the windings cool down. In this case it appears that the motor was overloaded and the thermal cutout failed to operate. (This is assuming that there was a thermal cutout)

To give you some idea of how much extra current can be drawn I will recount an example that I had occure in a cabinet shop that I owned.

One of my workers was routing round speaker holes in 3/4" chipboard. He had been told to do it in three goes, 1/4" at a time. He decided that was too slow and did it in one go. He was using a 3 1/2 HP (11.6A) router which was getting hot but as he had to set up the template each time it managed to cool down and keep going. Just for interest I put a meter on the router and it was drawing 7 1/2 HP (24.8A) during the cut.

Well over double its rating but because of the low duty cycle the fuses and the router survived and the worker kept going all day.

Hi Hilly,
I was having problems with my 240V reticulated supply nearly 3 years ago. The problem was over voltage with peaks up to 270V.
This was adjusted and then ranged between 255/227 Volts. I do not have a voltmeter on my house supply but I am tempted to ask Powercore
for a read out on D Day. As you say the waveform is not so very pure nor is the input volts to the home.
R.

Les.

As I recall, skeetas, there were mains monitoring gadgets that you could plug into power points to check on power consumption of devices that were connected to a power point. These also gave you a reading of the supply voltage. I doubt that the electricity supply people like the idea of consumers being able to actually measure the variations in supply voltage but it's only going to get worse rather than better, especially in rural and fringe urban areas. Domestic "back to the grid" solar systems cause voltage swings whenever the sun shines. I found that out at my neighbour's place when I was welding. The welder always worked better when the sun was shining and his solar system was putting power back into the grid. Designing a motor that works under these conditions must be a real challenge.