Circular Saw failure

[Trevor Wilson]

On 27/05/2017 11:08 AM, ~misfit~ wrote:

Once upon a time on usenet Sylvia Else wrote:
On 26/05/2017 8:05 PM, Trevor Wilson wrote:

Also, the manufacturers always quote the voltage, which is next to
meaningless, but never the power, so you really don't know what
you're getting.

**Tut-tut. I expected more from you that this. For battery
screwdrivers, almost all provide RPM and torque figures, which is
all you need to know. In a real sense, a modern brushless motor
drill, delivers more power than a 600 Watt 240VAC drill.

Perhaps it does. The drill may thus be consuming more than 600 watts
from its battery, which would be nice to know.

Or it could be that brushless DC motors are far more efficient than brushed
AC universal motors. Heck they (can) even do regenerative braking when you
let go of the power button!

**In fairness, ALL electric motors are very efficient. The worst being
around 75% (brush motors) and the best being around 95% (brushless).
Brushless DC motors offer smaller size, lighter weight, better
controllability, etc, etc though. Regenerative braking? In a drill?
Really?

--
Trevor Wilson
www.rageaudio.com.au

 

[~misfit~]

Once upon a time on usenet Trevor Wilson wrote:

On 27/05/2017 11:08 AM, ~misfit~ wrote:
Once upon a time on usenet Sylvia Else wrote:
On 26/05/2017 8:05 PM, Trevor Wilson wrote:

Also, the manufacturers always quote the voltage, which is next to
meaningless, but never the power, so you really don't know what
you're getting.

**Tut-tut. I expected more from you that this. For battery
screwdrivers, almost all provide RPM and torque figures, which is
all you need to know. In a real sense, a modern brushless motor
drill, delivers more power than a 600 Watt 240VAC drill.

Perhaps it does. The drill may thus be consuming more than 600 watts
from its battery, which would be nice to know.

Or it could be that brushless DC motors are far more efficient than
brushed AC universal motors. Heck they (can) even do regenerative
braking when you let go of the power button!


**In fairness, ALL electric motors are very efficient. The worst being
around 75% (brush motors) and the best being around 95% (brushless).

That's still an improvement of 20% efficiency or 120 watts in the above
example. 20% is a lot when running on a battery.

Brushless DC motors offer smaller size, lighter weight, better
controllability, etc, etc though. Regenerative braking? In a drill?
Really?

Maybe not in a drill but in a circular saw. I was reading the specs for one
a while back that recouped the energy of the blade brake (sorry no cite so
fwiw).
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

 

[Sylvia Else]

On 27/05/2017 2:47 PM, ~misfit~ wrote:

Maybe not in a drill but in a circular saw. I was reading the specs for one
a while back that recouped the energy of the blade brake (sorry no cite so
fwiw).

Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Sylvia.

 

[Clifford Heath]

On 27/05/17 16:19, Sylvia Else wrote:

On 27/05/2017 2:47 PM, ~misfit~ wrote:

Maybe not in a drill but in a circular saw. I was reading the specs
for one
a while back that recouped the energy of the blade brake (sorry no
cite so
fwiw).


Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.

 

[Phil Allison]

Clifford Heath the Chirping Cricket wrote:

-------------------------------------------

Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.

** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical theory at ALL??

Do not try to reply.

The answer has been obvious for DECADES.



..... Phil

 

[Clifford Heath]

On 27/05/17 19:49, Phil Allison wrote:

Clifford Heath the Chirping Cricket wrote:

-------------------------------------------



Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical theory at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.
Pointless maybe, but how is that hard to understand?

 

[Xeno]

On 27/05/2017 8:48 PM, Clifford Heath wrote:

On 27/05/17 19:49, Phil Allison wrote:
Clifford Heath the Chirping Cricket wrote:

-------------------------------------------



Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat -
but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical theory
at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.
Pointless maybe, but how is that hard to understand?

With DC motors there are easier ways to get one to stop quickly when
it's turned off. Your car's wiper motor does that. It's simple and it's
easy to incorporate. It's regenerative braking but you are not pumping
energy back into the battery so no complications there.

--

Xeno

 

[Phil Allison]

Clifford the FUCKWIT Chirping Cricket wrote:

and who was told NOT to reply

---------------------------------------------

Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical
theory at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.

** FFS - it will stop way FASTEST if the energy is dumped.

NOT recovered & STORED !!!

You know nothing trolling maggot.

 

[Clifford Heath]

On 27/05/17 23:19, Phil Allison wrote:

Clifford the FUCKWIT Chirping Cricket wrote:

and who was told NOT to reply

---------------------------------------------



Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical
theory at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.



** FFS - it will stop way FASTEST if the energy is dumped.
NOT recovered & STORED !!!
You know nothing trolling maggot.

Ok, but a dead short doesn't necessarily do that, as you know.
You need somewhere other than armature resistance to dump the
energy, and the battery is a reasonable place, assuming that
the armature is sufficiently high-Q to get it there. If not,
just short it.

How would *you* dump the energy?

 

[Clifford Heath]

On 27/05/17 23:04, Xeno wrote:

On 27/05/2017 8:48 PM, Clifford Heath wrote:
On 27/05/17 19:49, Phil Allison wrote:
Clifford Heath the Chirping Cricket wrote:

-------------------------------------------



Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat
- but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical theory
at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.
Pointless maybe, but how is that hard to understand?

With DC motors there are easier ways to get one to stop quickly when
it's turned off. Your car's wiper motor does that.

No, it doesn't. Regeneration requires more than just going
open or short circuit.

It's simple and it's easy to incorporate. It's regenerative braking but you are not pumping
energy back into the battery so no complications there.

Perhaps you can explain what you think "regeneration" means?
Because you certainly don't mean what everyone else means by it!

 

[Phil Allison]

Clifford the FUCKWIT Chirping Cricket wrote more CRAP.


---------------------------------------------

Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical
theory at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.



** FFS - it will stop way FASTEST if the energy is dumped.
NOT recovered & STORED !!!
You know nothing trolling maggot.

Ok, but a dead short doesn't necessarily do that, as you know.

** Shorting the armature is exactly how to stop the rotor FAST.

FOAD.


..... Phil

 

[Sylvia Else]

On 28/05/2017 11:02 AM, Phil Allison wrote:

Clifford the FUCKWIT Chirping Cricket wrote more CRAP.


---------------------------------------------





Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical
theory at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.



** FFS - it will stop way FASTEST if the energy is dumped.
NOT recovered & STORED !!!
You know nothing trolling maggot.

Ok, but a dead short doesn't necessarily do that, as you know.


** Shorting the armature is exactly how to stop the rotor FAST.

FOAD.


.... Phil

Putting a reverse voltage on it will stop it faster, and since the
current is in the opposite direction to the voltage, energy is being
pumped into whatever is presenting the voltage.

Sylvia.

 

[Phil Allison]

Stupider than Anyone Else wrote:

---------------------------------

Putting a reverse voltage on it will stop it faster,

** So will sticking a screwdriver in with the rotor.

The point remains that extracting the energy and storing it is gonna be a SLOWER way of braking the rotor.




..... Phil

 

[Sylvia Else]

On 28/05/2017 11:50 AM, Phil Allison wrote:

Stupider than Anyone Else wrote:

---------------------------------


Putting a reverse voltage on it will stop it faster,


** So will sticking a screwdriver in with the rotor.

The point remains that extracting the energy and storing it is gonna be a SLOWER way of braking the rotor.

The issue is the rate at which energy can be extracted. Whether the
energy is stored or dissipated is irrelevant. The higher the reverse
voltage the faster the blade will stop, and the faster the energy is
extracted.

The design issue is then how to provide the reverse voltage, and what to
do with the energy.

Sylvia.

 

[Xeno]

On 28/05/2017 7:58 AM, Clifford Heath wrote:

On 27/05/17 23:04, Xeno wrote:
On 27/05/2017 8:48 PM, Clifford Heath wrote:
On 27/05/17 19:49, Phil Allison wrote:
Clifford Heath the Chirping Cricket wrote:

-------------------------------------------



Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat
- but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical theory
at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.
Pointless maybe, but how is that hard to understand?

With DC motors there are easier ways to get one to stop quickly when
it's turned off. Your car's wiper motor does that.

No, it doesn't. Regeneration requires more than just going
open or short circuit.

It's simple and it's easy to incorporate. It's regenerative braking
but you are not pumping
energy back into the battery so no complications there.

Perhaps you can explain what you think "regeneration" means?
Because you certainly don't mean what everyone else means by it!

In this case, it serves to retard the motion of the armature. Works very
well on wiper motors - stops them dead. Isn't that the aim here -
stopping a motor quickly?

--

Xeno

 

[Xeno]

On 28/05/2017 11:02 AM, Phil Allison wrote:

Clifford the FUCKWIT Chirping Cricket wrote more CRAP.


---------------------------------------------





Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical
theory at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.



** FFS - it will stop way FASTEST if the energy is dumped.
NOT recovered & STORED !!!
You know nothing trolling maggot.

Ok, but a dead short doesn't necessarily do that, as you know.


** Shorting the armature is exactly how to stop the rotor FAST.

FOAD.


..... Phil

It definitely works, every car wiper system, save for vacuum ones, works
on precisely that principle and they have done so for as long as I can
recall.

--

Xeno

 

[Xeno]

On 28/05/2017 11:39 AM, Sylvia Else wrote:

On 28/05/2017 11:02 AM, Phil Allison wrote:

Clifford the FUCKWIT Chirping Cricket wrote more CRAP.


---------------------------------------------





Pumping the energy back into the battery may be a convenient way of
dealing with it - otherwise it would have to be dissipated as
heat - but
I doubt it's worth doing for the sake of the recovered energy.

Worth doing if only to make the blade stop quickly.



** Wot fucking ASSININE CRAP !!!!!!!!!!!!

The blade will stop WAAAAAYYYY faster if you DO NOT DO THAT !!!!

Do you fucking know ANY engineering, electronics or electrical
theory at ALL??

Do not try to reply.

The answer has been obvious for DECADES.

WAT?

There's energy in the rotating blade.
If you remove the energy, it stops faster.



** FFS - it will stop way FASTEST if the energy is dumped.
NOT recovered & STORED !!!
You know nothing trolling maggot.

Ok, but a dead short doesn't necessarily do that, as you know.


** Shorting the armature is exactly how to stop the rotor FAST.

FOAD.


.... Phil


Putting a reverse voltage on it will stop it faster, and since the
current is in the opposite direction to the voltage, energy is being
pumped into whatever is presenting the voltage.

Sylvia.

Shorting the armature stops it really quickly in the simplest manner
possible.

--

Xeno

 

[Xeno]

On 28/05/2017 12:50 PM, Sylvia Else wrote:

On 28/05/2017 11:50 AM, Phil Allison wrote:

Stupider than Anyone Else wrote:

---------------------------------


Putting a reverse voltage on it will stop it faster,


** So will sticking a screwdriver in with the rotor.

The point remains that extracting the energy and storing it is gonna
be a SLOWER way of braking the rotor.


The issue is the rate at which energy can be extracted. Whether the
energy is stored or dissipated is irrelevant. The higher the reverse
voltage the faster the blade will stop, and the faster the energy is
extracted.

The design issue is then how to provide the reverse voltage, and what to
do with the energy.

Sylvia.

That's what I thought shorting the armature was doing.

--

Xeno

 

[Phil Allison]

Stupider than Anyone Else COMPOUNDS the error:

----------------------------------------------

Putting a reverse voltage on it will stop it faster,


** So will sticking a screwdriver in with the rotor.

The point remains that extracting the energy and storing it is gonna be a SLOWER way of braking the rotor.


The issue is the rate at which energy can be extracted. Whether the
energy is stored or dissipated is irrelevant.

** The issue is exactly what I wrote above.

Clifford is WRONG and so are you.

And you are Both TROLLS.


..... Phil

 

[Sylvia Else]

On 28/05/2017 12:57 PM, Xeno wrote:

On 28/05/2017 12:50 PM, Sylvia Else wrote:
On 28/05/2017 11:50 AM, Phil Allison wrote:

Stupider than Anyone Else wrote:

---------------------------------


Putting a reverse voltage on it will stop it faster,


** So will sticking a screwdriver in with the rotor.

The point remains that extracting the energy and storing it is gonna
be a SLOWER way of braking the rotor.


The issue is the rate at which energy can be extracted. Whether the
energy is stored or dissipated is irrelevant. The higher the reverse
voltage the faster the blade will stop, and the faster the energy is
extracted.

The design issue is then how to provide the reverse voltage, and what
to do with the energy.

Sylvia.

That's what I thought shorting the armature was doing.

Shorting the armature causes the energy to be dissipated in the
armature. Since the resistance of the armature isn't that high, it takes
a while.

Sylvia.