Brushless motors

[Allen Edge]

Reading the posts concerning brushless motors.  I am currently restoring a Victorian home in Connecticut. Per electric code all the kitchen outlets have to be duel fault .  This means one cannot use a Festool ( vacuum or other corded tool from Festool) in the kitchen without popping the breaker due to the tool having a brushed motor and thus a small spark which shuts down the breaker as the breaker is designed to do.I have had to run an extension cord to another room to be able to operate the Festool vac.  It is a pretty minor inconvenience but an annoyance nonetheless. 

 

[Michael Kellough]

Reading the posts concerning brushless motors.  I am currently restoring a Victorian home in Connecticut. Per electric code all the kitchen outlets have to be duel fault .  This means one cannot use a Festool ( vacuum or other corded tool from Festool) in the kitchen without popping the breaker due to the tool having a brushed motor and thus a small spark which shuts down the breaker as the breaker is designed to do.I have had to run an extension cord to another room to be able to operate the Festool vac.  It is a pretty minor inconvenience but an annoyance nonetheless.

So, you can’t use a blender in the kitchen?  [blink]

 

[jaguar36]

Something else going on there, no reason Festool vacs or other tools using brushed motors in good condition should be tripping a dual fault breaker.  Either the Festool is in poor shape and has a broken conductor arcing very badly, or there is a wiring or breaker issue.  The Arc Fault portion of the 'Dual' function breaker should not trip based on the small arcs that occur in brushed motors (or switches and plugs).

Almost all kitchen appliances are brushed motors as well.

 

[gharel2]

I actually had the opposite problem where I had been using a MIDI, Trion, ETS 125, Domino, OF1400 all with no problem. Then I plugged in the ETS EC 150 and it immediately popped the AFCI breaker. Customer support seemed to think that was normal/expected behavior.

 

[squall_line]

This thread reminds me that I hope to be able to put off any electrical work in my home until AFCI breakers have matured another 5-10 years.  There are too many "false trips" reported, anecdotally or otherwise, for me to trust that it's all sorted out.

That, and it would be nice if the prices came down a little bit.

 

[waho6o9]

Fascinating thread. Good posts

 

[Cheese]

Just curious if it's a Siemens breaker...have heard they do have issues.

 

[slavi.yordanov]

This thread reminds me that I hope to be able to put off any electrical work in my home until AFCI breakers have matured another 5-10 years.  There are too many "false trips" reported, anecdotally or otherwise, for me to trust that it's all sorted out.

That, and it would be nice if the prices came down a little bit.

I have all AFCI breakers as per
building code. My panel Square D QO, and I have rarely had false trips, if any.

 

[mino]

Something else going on there, no reason Festool vacs or other tools using brushed motors in good condition should be tripping a dual fault breaker.  Either the Festool is in poor shape and has a broken conductor arcing very badly, or there is a wiring or breaker issue.  The Arc Fault portion of the 'Dual' function breaker should not trip based on the small arcs that occur in brushed motors (or switches and plugs).

Almost all kitchen appliances are brushed motors as well.

A more likely problem is the breaker not working (properly) on the ground fault side. "Older" standard GFCI breakers were 30mA while the new "dual ones" seem to have gone > 5 mA. I.e. 6x more sensitive than before.

Even with the 30 mA ones standard, there were devices which needed a 300 mA breaker to be used instead.

With the high-powered full-wave electronic motor control units there can be small (way beyond safe) capacitive current transients seen on the ground wires. If the GFCI part of the breaker is too sensitive - in this case a bad design/cheap one will be the more "sensitive" one - it may trip under an otherwise normal within-spec operation.

Most kitchen appliances *) are not grounded these days, hence the GFCI "issue" would not be observed. Same for most home vacs.

*) meaning hand-use ones

 

[alltracman78]

I'll echo that a brushed motor shouldn't be a problem. Most electric motors in the house use brushes. Ceiling fans, appliances, pellet stoves, ect.

Weird that the kitchen requires AFCI? I'm not necessarily up to the minute informed on code but usually kitchen/bath/basement/garage requires GFCI while pretty much everything else requires AFCI.

 

[woodferret]

I'll echo that a brushed motor shouldn't be a problem. Most electric motors in the house use brushes. Ceiling fans, appliances, pellet stoves, ect.

Weird that the kitchen requires AFCI? I'm not necessarily up to the minute informed on code but usually kitchen/bath/basement/garage requires GFCI while pretty much everything else requires AFCI.

NEC 2017 expanded to the point where if you even glanced at an outlet, you'd need to replace it with an AFCI.  /s 

 

[Coen]

Something else going on there, no reason Festool vacs or other tools using brushed motors in good condition should be tripping a dual fault breaker.  Either the Festool is in poor shape and has a broken conductor arcing very badly, or there is a wiring or breaker issue.  The Arc Fault portion of the 'Dual' function breaker should not trip based on the small arcs that occur in brushed motors (or switches and plugs).

Almost all kitchen appliances are brushed motors as well.

A more likely problem is the breaker not working (properly) on the ground fault side. "Older" standard GFCI breakers were 30mA while the new "dual ones" seem to have gone > 5 mA. I.e. 6x more sensitive than before.

Even with the 30 mA ones standard, there were devices which needed a 300 mA breaker to be used instead.

With the high-powered full-wave electronic motor control units there can be small (way beyond safe) capacitive current transients seen on the ground wires. If the GFCI part of the breaker is too sensitive - in this case a bad design/cheap one will be the more "sensitive" one - it may trip under an otherwise normal within-spec operation.

Most kitchen appliances *) are not grounded these days, hence the GFCI "issue" would not be observed. Same for most home vacs.

*) meaning hand-use ones

30 mA is lower limit 15, uppper limit 30. Older ones sat often at the upper edge... say 25.. 28. Newer onces often 20...22
There has also been an explosion of power supplies with netfilters that always leak a little bit.

Also, previous type GFCI was not sensitive to half-wave earth faults. In fact... it made it also insensitive to full wave faults.

The home vacs are annoying as f*ck with their static buildup. They should get them the 3-pin cord to be able to bleed off the static, just like Festool vacs