Questions about powering the TS75 with a CT dust extractor

[atlr]

I am considering the purchase of a TS75 since the TS55R is not currently available.

I am concerned that the CT dust extractor is sold to power the TS55 and TS75 when the CT does not seem capable of supplying the maximal current draw of the saws across the range of suction power according to its specification. (Yes, it's true; I have time to think too much.) This topic has come up over the years which I have noted below. Clearly, the combination of CT and TS works but I wonder if the risk of fire or CT failure is underestimated.

Are there documentation supplements that warn one to power the TS55 or TS75 on circuits separate from the CT?  Or does the dust extractor automatically reduce to the lowest speed when using a TS on tough material?

From the CT 26E/36E manual, the dust extractor can draw currents between 2.9 to 10 A from low speed to high speed.  Current supplied to the accessory connection from low speed to high speed of a CT dust extractor is specified to be 9.1 A down to 3.7 A (or possibly 2 A).  The maximal current draw spec of a CT is 12 A.

The maximal current draw spec of a TS55 from its manual is 10 A.
The maximal current draw spec of a TS75 from its manual is 13 A.

I wonder what an IR image of a 15 A or 20 A circuit breaker while connected to a CT powering a TS75 cutting through some tough material would show?  Or an IR image of a CT power supply board?

Here are some of the past discussions about this topic.

circa 2012 observation that the TS55 draws about 10-15 A on start up and 5-8 A in operation in the end-user's environment
http://festoolownersgroup.com/festool-tools-accessories/ts55-festool-dust-extractor-question/

circa 2012 discussion about maximal current draw of OF2200 is about 20 amps and the ramification of powering it with a Festool vac
http://festoolownersgroup.com/festool-tools-accessories/power-ratings/

circa 2010 discussion about the CT36 on manual will not power a TS75
http://festoolownersgroup.com/festool-tool-problems/ct36-problem/

circa 2007 statement from an end-user that the Festool vac is designed to draw 20 A. I am not sure how he knows of the 20 A value.
http://festoolownersgroup.com/festool-tools-accessories/what-don't-you-like-about-festool/msg1771/#msg1771

circa 2007 discussion about 110v MIDI vac spec of this era not spec-ed to support accessories that draw more than about 4 A
http://festoolownersgroup.com/festool-tools-accessories/midi-vac/msg10307/#msg10307

 

[semenza]

It shouldn't be a problem. I have run the TS75  cutting  1 3/4" thick birch heartwood ( it was very dense) for quite a lot of cuts ripping with the Universal blade and also rip / jointing cuts with the Fine blade. There was a pretty heavy load on the saw but no power issues  running it through the CT.

Seth

 

[rljatl]

Wouldn't the circuit breaker trip if it got too hot or the current draw was more than the breaker allows?  

I have the TS75 and a CT26.  Zero problems.  Plenty of power, no tripped circuit breakers.  Glad I got the 75.  Vac works great.  Use a pigtail to avoid the CT vac's potential loose outlet problem.

P.S.  I got both the vac and saw from the Woodcraft near where you live.  Ask for Robert.

 

[atlr]

I just read up on circuit breakers and now understand that most residential circuit breakers open according to a time versus current and ambient temperature relationship.  For example, a 15 A circuit breaker does not instantly trip on a 16 A load.  It depends on how long the overload lasts.

My home uses an Eaton/Cutler-Hammer 15 A circuit breaker so I will use its trip curve for an example.
http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&noSaveAs=0&Rendition=Primary&dDocName=1063683065156

Using the graph on page 1 of the linked document, the Eaton/Cutler-Hammer Type BR 15 A circuit breaker will likely trip sometime after 40 seconds to 25 minutes (1500 seconds) when a TS75 and CT36 run continuously at maximum current, 13 A and 10A respectively, which is is about 150% (23 A/15 A) of the breakers 15 A rating. 

I still wonder how long the CT will run when current draw hits 23 A.  Does the CT have an internal breaker or fuse that can be reset by the user?

 

[atlr]

That 40 second to 25 minute 15 A circuit breaker trip time range is at an ambient temperature of 104 F.    My eyeball extrapolation of the 25 C/77 F graph is that  maximum circuit breaker trip time is about at the 1.5 hour point of continuous operation at maximum current draw.

Again, yes, I have too much time to think about this.

 

[Guilliaume woodworks]

Atlr,          I believe it when you say you have to much time on your hands. Do yourself ( & us ) a favor and go get the saw with vac.  Trust me, nothing is going to catch fire or melt . Have fun & report back.

 

[jonny round boy]

Atlr,           I believe it when you say you have to much time on your hands. Do yourself ( & us ) a favor and go get the saw with vac.  Trust me, nothing is going to catch fire or melt . Have fun & report back.

Ditto. You're thinking about this far too much!

 

[atlr]

Tis true. Comes from Professional Engineers pounding "specs matter" into me.

 

[fdengel]

Something else to consider:

Electronic devices often pull maximum current immediately after being switched on ("inrush current") then drop down to lower levels.

My guess is that the "smooth start-up" of the CT vacs delays their maximum current draw by just enough to avoid it happening at the same time as that of the tool.  Assuming that is true, the two devices would not be hitting maximum current draw at the same time, which might be enough to prevent this from becoming an issue?

There is probably a meter of some sort that could be used to measure what is actually being pulled by the devices; might be interesting to check this sometime... at any rate, I'd rather be using the tools than bothering with all the analysis...  8)

 

[gkaiseril]

Do not forget that the extension cords can also affect the current being drawn. Those 18 gauge cords cause all sorts of issues at 100 feet or 33 meters.