# Neutral Timing is Better for Commuters



## EVDL List (Jul 27, 2007)

Hi,

I stopwatch checked my acceleration starting in 2nd gear going from 2 fixed 
points uphill 10% grade between my drive & the neighbors. I tried 7 degrees 
mechanical advance and then set it back to neutral on my Prestolite MTC4001 
at 96V E-Porsche 16 ni-cads. I got 33 seconds at 7 degrees and 25 seconds 
at neutral and it popped up my 30% grade garage better too with neutral 
timing. I checked at speed holding hills and it was at 3600 rpms in 3rd 
doing 60mph at 250 amps on the same section of highway. I noticed a bit 
drop-off above that speed but overall it ran better with better acceleration 
set to neutral. I think the low voltage and rpm's are the factor.

The racers are operating at higher voltage and higher RPM's I believe where 
the performance is noticed about 5-6k rpm's

Best Regards,
Mark

_________________________________________________________________
http://newlivehotmail.com


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## EVDL List (Jul 27, 2007)

Hi Mark,


It's great to see you doing some real tests and
sharing. 25 to 33 seconds is more than I expected. 
Remember a few weeks ago. I said:

"Chances are you have a 4 pole motor. And your 7
degree figure is actual or mechanical degrees. So you
really have it advanced 14 electrical degrees. If you
advanced it 45 mech degrees (90 elect degrees) you
would have zero torque. I am not sure it is a linear
relationship, but it might give you a feeling. 7
divided by 45 equals 0.155. So your 7 degree shift
might result in 16 percent less torque at current
limit.

Acceleration is proportional to torque. So does 7
degrees equal 16% less torque equal 16% slower accel? 
Give it try and let us know."

Your tests don't sound 100 percent scientific, but do
show show a trend. Now, if commutation (sparking) was
acceptable, you've got something.

BTW, I didn't realize you had the MTC-4001. The
factory shift was 4.5 degrees. Did you go 7 degrees
further? Or total?

Jeff






> --- Mark Hanson <[email protected]> wrote:
> 
> > Hi,
> >
> ...


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## EVDL List (Jul 27, 2007)

Hi Mark and all,

Have you tried to tune your motor for best amp draw? It just takes an
ammeter hooked to your setup while running. fix the motor at a steady
voltage then play with the timing untill you draw the least amps. That
should be the sweet spot. Lawrence Rhodes.......
----- Original Message ----- 
From: "Mark Hanson" <[email protected]>
To: <[email protected]>
Sent: Monday, July 30, 2007 5:26 AM
Subject: Neutral Timing is Better for Commuters


> Hi,
>
> I stopwatch checked my acceleration starting in 2nd gear going from 2
fixed
> points uphill 10% grade between my drive & the neighbors. I tried 7
degrees
> mechanical advance and then set it back to neutral on my Prestolite
MTC4001
> at 96V E-Porsche 16 ni-cads. I got 33 seconds at 7 degrees and 25 seconds
> at neutral and it popped up my 30% grade garage better too with neutral
> timing. I checked at speed holding hills and it was at 3600 rpms in 3rd
> doing 60mph at 250 amps on the same section of highway. I noticed a bit
> drop-off above that speed but overall it ran better with better
acceleration
> set to neutral. I think the low voltage and rpm's are the factor.
>
> The racers are operating at higher voltage and higher RPM's I believe
where
> the performance is noticed about 5-6k rpm's
>
> Best Regards,
> Mark
>
> _________________________________________________________________
> http://newlivehotmail.com
>


----------



## EVDL List (Jul 27, 2007)

Hi Jeff,

I didn't realize the MTC-4001 was advanced 4.5 degrees, which way? There 
were only single holes not 2 options for neutral or advanced so I don't see 
how they would manufacture a motor not knowing the direction of the 
application. I advanced the motor 7 degrees turning the brush end CCW into 
the CW motor direction with the vehicle forward motion and tapped 4 new 
1/4-20 holes for that setting.

(Advance DC engineer said their motors are *not* advanced since they don't 
know the user direction or application).

best Regards,
Mark

Date: Mon, 30 Jul 2007 07:46:29 -0700 (PDT)
From: Jeff Major <[email protected]>
Subject: Re: Neutral Timing is Better for Commuters
To: [email protected]
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
Message-ID: <[email protected]>


Hi Mark,


It's great to see you doing some real tests and
sharing. 25 to 33 seconds is more than I expected.
Remember a few weeks ago. I said:

"Chances are you have a 4 pole motor. And your 7
degree figure is actual or mechanical degrees. So you
really have it advanced 14 electrical degrees. If you
advanced it 45 mech degrees (90 elect degrees) you
would have zero torque. I am not sure it is a linear
relationship, but it might give you a feeling. 7
divided by 45 equals 0.155. So your 7 degree shift
might result in 16 percent less torque at current
limit.

Acceleration is proportional to torque. So does 7
degrees equal 16% less torque equal 16% slower accel?
Give it try and let us know."

Your tests don't sound 100 percent scientific, but do
show show a trend. Now, if commutation (sparking) was
acceptable, you've got something.

BTW, I didn't realize you had the MTC-4001. The
factory shift was 4.5 degrees. Did you go 7 degrees
further? Or total?

Jeff






> --- Mark Hanson <[email protected]> wrote:
> 
> >Hi,
> >
> ...


----------



## EVDL List (Jul 27, 2007)

Mark,

MTC-4001 was designed for Jet Ind ElectraVan. It used
the Subaru tranny with reverse. So the MTC motor
would only be driven one direction. I forget which,
CW or CCW. But Prestolite used a 4 terminal frame,
S1,S2,A1,A2, and put an external jumper strap from S2
to A2. So the user would have a two terminal
unidirectional motor to work with. Because the
rotation direction was known ahead of time, the
standard MJU-2x comm end head was used which had the
holes for frame mount offset 4.5 degrees. These MJU-2
die cast comm end heads were used for unidirectional
pump motors and reversible traction motors on
Prestolite's standard line for lift trucks. One MJU-2
version with holes neutral for reversible, and
different versions with holes offset one way or the
other for unidirectional pump motors. This is
apparent when you look at the screw heads in the MJU-2
casting. There is a relief. If the screw is in the
middle of the relief, it is neutral. But there is
room such that the holes can be drilled 4.5 degrees
either way.

The 4 terminal frame was used on the MTC-4001 for
standardization of subassemblies and also to give the
user access to the field in case he wished to used
field weakening.

Like I said, I don't recall which was the standard
rotation for MTC-4001. But if you're using the
original equipment strap, you're going the correct
way. That would be A1 to S1 or A2 to S2. That strap
went parallel to the shaft axis. If you have the S to
A jumper skewed around the frame, then it is contrary.

So, it sounds to me like you went from 4.5 to 11.5
degrees advanced. Would explain larger than expected
loss of torque. I suspect the first few degrees of
advance not to diminish torque as much as further on.

Is this a Jet vehicle? Got it on the EValbum?

Hope this helps.

Jeff



> --- Mark Hanson <[email protected]> wrote:
> 
> > Hi Jeff,
> >
> ...


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## EVDL List (Jul 27, 2007)

Hey all

I haven't had the time I've wanted to address my
thoughts toward brush timing like I'd like. Rather
than watch another timing thread go by I thought I'd
throw some thoughts at the group.

Most DC motors are designed to be ran neutral and at a
particular voltage, and in fact I spent most of my
first 25 years building motors making sure they went
out that way (older forklift motors had adjustable
brush rings). It wasn't until I ran into Wayland that
I had to start learning how and when to throw them out
of wack, so to speak.

So why advance the brushes when neutral is more eff? 

The first issue (for those that are new) is when the
motor commutator arcs in what's been termed a
flashover. This is caused by using higher voltages
than the motor was intended for, which causes the
field magnetics to shift which in turn causes the
brushes to arc as they are no longer "in tune" with
the fields. By advancing the brushes they line up
with the fields when the motor is seeing that higher
voltage and is running harder. 

By advancing the brushes you also see the motors power
band shift further up the RPM scale. I've had reports
of both "love" and "hate" increased advancement. The
problem is "when to advance"? 

It was just last year that Pat Sweeney flashed his
daily driver ADC motor, when he did it a second time,
he sent it to me, where I found it running in neutral.
After some cleanup and a few parts and setting it via
the OEM advancement holes he's had no issues, besides
a little loss on his takeoff 8^(

Sometimes lifes a trade off, lose a little eff, or
repair your motor a lot 8^P Now this doesn't apply to
lower voltage EV's as much, but again that depends a
lot on what motor one is using compared to what
voltage it's being run at. 

I haven't heard from Bill as to when the brush shift
was taking place on Killacycle, or how well he and
scotty thought it was working but it was, I thought, a
successful test of an on the fly brush timing shift. 
Being able to smoothly adjust the timing on DC motors
as they run (just like an ICE) would help squeeze both
better eff as well as performance.

As I'm running short of time my advise to those in
doubt is to advance the brushes and avoid themselves
the costs of motor repairs. As Jeff's done a great
write up on this MTC motor, I thought I'd post a bit
for those not using the standard fare motors 8^)

BTW Jeff, I know exactly what you meant with the MJU
plates 8^) I'll see if I can dig some plates out (if
I have any) and grab some pics of the different hole
positions per your description.

Anyway, yeah neutrals better for you dailies... right
up to the point when you zorch your motor. IMO it's
kind of like condom use, do you really want to chance
"not" using it 8^) Of course the higher the juice
flow the more that it's needed 8^o

Hope this helps
Had fun
Jim Husted
Hi-Torque Electric




____________________________________________________________________________________
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## EVDL List (Jul 27, 2007)

Hey Jim, I pretty much agree with you on this. If in doubt advance. When 
you mention high voltage you do not mention parameters. High voltage is a 
very nebulous term. When I was first involved with EVs I would say that 120 
volts was high voltage. Advanced DC motors used to come with three sets of 
holes, one neutral, one advanced about seven degrees and one for clockwise 
rotation. This worked great up to about 144 volts. When Advanced DC set 
their brushes to neutral for Sparrows and upped the rating of their stock 8 
inch to a name plate rating of 156 volts they ran into all kinds of 
problems. They almost drove one small controller manufacturer out of 
business. They did not realize that people do not go in reverse as fast as 
they do in forward. This little piece of information that was missing from 
their brains was disastrous for many consumers. Like I said, it is all 
nebulous and depends on the motor and the voltage but I personally would 
never recommend that a commuter vehicle run no advance above say 96 volts. I 
guess this may just be my opinion. You should ask some of the early Sparrow 
owners and others for real life scenarios.

Roderick

Roderick Wilde
Vintage Golf Cart Parts
Specializing in Parts for Harley and many other mature carts
www.vintagegolfcartparts.com
E-mail: [email protected]
Phone: 360-385-4868
P.O. Box 221
Port Townsend, WA 98368


----- Original Message ----- 
From: "Jim Husted" <[email protected]>
To: <[email protected]>
Sent: Monday, July 30, 2007 8:57 PM
Subject: Re: Neutral Timing is Better for Commuters


> Hey all
>
> I haven't had the time I've wanted to address my
> thoughts toward brush timing like I'd like. Rather
> than watch another timing thread go by I thought I'd
> throw some thoughts at the group.
>
> Most DC motors are designed to be ran neutral and at a
> particular voltage, and in fact I spent most of my
> first 25 years building motors making sure they went
> out that way (older forklift motors had adjustable
> brush rings). It wasn't until I ran into Wayland that
> I had to start learning how and when to throw them out
> of wack, so to speak.
>
> So why advance the brushes when neutral is more eff?
>
> The first issue (for those that are new) is when the
> motor commutator arcs in what's been termed a
> flashover. This is caused by using higher voltages
> than the motor was intended for, which causes the
> field magnetics to shift which in turn causes the
> brushes to arc as they are no longer "in tune" with
> the fields. By advancing the brushes they line up
> with the fields when the motor is seeing that higher
> voltage and is running harder.
>
> By advancing the brushes you also see the motors power
> band shift further up the RPM scale. I've had reports
> of both "love" and "hate" increased advancement. The
> problem is "when to advance"?
>
> It was just last year that Pat Sweeney flashed his
> daily driver ADC motor, when he did it a second time,
> he sent it to me, where I found it running in neutral.
> After some cleanup and a few parts and setting it via
> the OEM advancement holes he's had no issues, besides
> a little loss on his takeoff 8^(
>
> Sometimes lifes a trade off, lose a little eff, or
> repair your motor a lot 8^P Now this doesn't apply to
> lower voltage EV's as much, but again that depends a
> lot on what motor one is using compared to what
> voltage it's being run at.
>
> I haven't heard from Bill as to when the brush shift
> was taking place on Killacycle, or how well he and
> scotty thought it was working but it was, I thought, a
> successful test of an on the fly brush timing shift.
> Being able to smoothly adjust the timing on DC motors
> as they run (just like an ICE) would help squeeze both
> better eff as well as performance.
>
> As I'm running short of time my advise to those in
> doubt is to advance the brushes and avoid themselves
> the costs of motor repairs. As Jeff's done a great
> write up on this MTC motor, I thought I'd post a bit
> for those not using the standard fare motors 8^)
>
> BTW Jeff, I know exactly what you meant with the MJU
> plates 8^) I'll see if I can dig some plates out (if
> I have any) and grab some pics of the different hole
> positions per your description.
>
> Anyway, yeah neutrals better for you dailies... right
> up to the point when you zorch your motor. IMO it's
> kind of like condom use, do you really want to chance
> "not" using it 8^) Of course the higher the juice
> flow the more that it's needed 8^o
>
> Hope this helps
> Had fun
> Jim Husted
> Hi-Torque Electric
>
>
>
>
> 
> ____________________________________________________________________________________
> Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user 
> panel and lay it on us. 
> http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
>
>
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.476 / Virus Database: 269.10.25/926 - Release Date: 7/29/2007 
> 11:14 PM
>
>


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## EVDL List (Jul 27, 2007)

Dumb question time:
Can you rig an advance mechanism that would retard/advance the brushes in relation to RPM and/or volts/amps?


David C. Wilker Jr.
USAF (RET)



> ---- Jim Husted <[email protected]> wrote:
> Hey all
> 
> I haven't had the time I've wanted to address my
> ...


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## EVDL List (Jul 27, 2007)

You would first have to know how the neutral plane of the fields advances with increasing voltage, current and RPM. This would be no trivial task to figure out for any particular motor. And it would most likely be as different for different motors as the Torque curves. That being said though there is already one example of a single step shift at some point in the RPM band for Killacycle. For them its good before and good after the shift, so I guess it works. To vary the timing continuously with RPM may be add a little more complexity than its worth. But I'm sure it can be done, and most likely will someday as these racers start fighting for hundredths of seconds 

Mike,
Anchorage, Ak.

> -----Original Message-----
> From: [email protected] [mailto:[email protected]]On
> Behalf Of David Wilker
> Sent: Monday, July 30, 2007 9:14 PM
> To: [email protected]
> Cc: Jim Husted
> Subject: Re: Neutral Timing is Better for Commuters
> 
> 
> Dumb question time:
> Can you rig an advance mechanism that would retard/advance the brushes in relation to RPM and/or volts/amps?
> 
> 
> David C. Wilker Jr.
> USAF (RET)


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## EVDL List (Jul 27, 2007)

Yes, you can, and it's even easier if you do it in
software (using IGBTs instead of brushes and
commutators). Oops, I hope I'm not fanning the AC/DC
debate 


> > Dumb question time:
> > Can you rig an advance mechanism that would
> retard/advance the brushes in relation to RPM and/or
> volts/amps?
> > 
> > 
> > David C. Wilker Jr.
> > USAF (RET)
> 
> 




____________________________________________________________________________________
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Check out fun summer activities for kids.
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## EVDL List (Jul 27, 2007)

It's probably been covered before, but interpoles in a dc motor are the 
automatic electric way to change brush timing to reduce arcing. The field 
magnetic strength is shifted in proportion to armature current.






On Tue, 31 Jul 2007 05:39:08 -0700 (PDT), Steven Ciciora wrote
> Yes, you can, and it's even easier if you do it in
> software (using IGBTs instead of brushes and
> commutators). Oops, I hope I'm not fanning the AC/DC
> debate 
> 
> > > Dumb question time:
> > > Can you rig an advance mechanism that would
> > retard/advance the brushes in relation to RPM and/or
> > volts/amps?
> > > 
> > > 
> > > David C. Wilker Jr.
> > > USAF (RET)
> > 
> >
> 
> 
_____________________________________________________________________________
_______
> Got a little couch potato? 
> Check out fun summer activities for kids.
> http://search.yahoo.com/search?
fr=oni_on_mail&p=summer+activities+for+kids&cs=bz


----------



## EVDL List (Jul 27, 2007)

Can you rig an advance mechanism that would retard/advance the brushes in relation to RPM and/or volts/amps?


The more advanced brushless DC motor controllers (UQM, for example) do this automagically - it's only software. I know my brushless DC controllers do not (Solectria BRLS-240 + BRLS-16) but when timing the motors (you still have an adjustable hall-effect sensor), you can have the timing pretty much anywhere and there's no arcing. But that's silicon instead of carbon for my commutator. 

Mechanically it is possible, you need to have guides that allow you to attach some kind of servo to move the brushes - like the contact breaker plate in an old mechanical distributor.

-Dale


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## EVDL List (Jul 27, 2007)

Couldn't you do it just like the old distributer spark advance system?
Physically rotate the device in relation to its normally operating 
position.
Old distributors used the vacuum from the engine to do it.



> Dale Ulan wrote:
> > Can you rig an advance mechanism that would retard/advance the brushes
> > in relation to RPM and/or volts/amps?
> >
> ...


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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

> --- Dale Ulan <[email protected]> wrote:
> 
> > The more advanced brushless DC motor controllers
> > (UQM, for example) do this automagically - it's only
> ...


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## EVDL List (Jul 27, 2007)

I have seen a patent where a second set of brushes sense the armature
voltage and cause a small motor to rotate the brushes to minimize this
voltage. As I remember, this was intended for railway motor use.

Being no motor expert by far, I may be all wet, but this thread
surprises me because, as I understand it, the need for brush advance is
due to "armature reaction". This is where the magnetic field developed
by the armature, which is normally perpendicular to the stator field,
causes an effective shift in the stator field. This makes the "magnetic
neutral" position of the brushes different than the "geometric neutral".
I would expect this effect to be more at low rpm/high torque(high
current and high fields) than at lower current and high RPM.

Perhaps inductance, hysteresis and eddy currents are the dominat factors
at high RPM and need the same sort of brush offset. Without further
reflection, it would seem so since the main problem with lack of brush
offset is at high RPM and high voltage.

Allen

-----Original Message-----
From: David Wilker [mailto:[email protected]] 
Sent: Tuesday, July 31, 2007 12:14 AM
To: [email protected]
Cc: Jim Husted
Subject: Re: Neutral Timing is Better for Commuters

Dumb question time:
Can you rig an advance mechanism that would retard/advance the brushes
in relation to RPM and/or volts/amps?


David C. Wilker Jr.
USAF (RET)



> ---- Jim Husted <[email protected]> wrote:
> Hey all
> 
> I haven't had the time I've wanted to address my
> ...


----------



## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

Allen,

The armature reaction and field distortion causes
arcing at the high currents in the series motor, which
is mostly at lower RPM. Arcing also occurs at high
voltage due to the higher voltage between comm
segments. Also it will increase with RPM because the
current is forced to chance faster in the armature
coil which has inductance.

So the best location for the brush is a function of
all of the above.

Jeff




> --- "Bukosky, Allen" <[email protected]> wrote:
> 
> > I have seen a patent where a second set of brushes
> > sense the armature
> ...


----------



## EVDL List (Jul 27, 2007)

> --- Roderick Wilde <[email protected]> wrote:
> 
> > Hey Jim, I pretty much agree with you on this. If
> > in doubt advance. When
> ...


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## EVDL List (Jul 27, 2007)

I was thinking if i had an adjustable rigging that is spring returned
and advanced with a cable, I could try a "real McCoy" set up.

An adjustable set of counterweights spin relative to the motor rpm and
pull on a plate containing a bearing with the cable mounted on it.

It might also make an interesting hood ornament if we have that contest
again.


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## EVDL List (Jul 27, 2007)

Another idea I had on the "why bother" list is an inside out series dc
motor.

What if you could put the fields on the center rotating piece and the
com bars around the inside of the case. the brushes no go on a plate
like the old chevy distributers, Racers could change the springs and
counter weighs as needed and the ability to put snubbers or caps across
the comm segements to reduce arcing becomes feasable. The down side is
you would need slip rings to get the power to the plate. :-(

But maybe there is an interesting compromise
What if the ABR(adjustable brush rigging had a pair of pins(cam
rollers) sticking thru slots in the end bell of a motor with the
extended shaft . Attached to end bell is a metal cup that is spring
returned and has slots in it the cam roller pins ride in. Attacthe to
the shaft is a fairly big permanent magnet. As it spins faster, it pulls
harder on the can which moves the ABR plate. kinda like a really big
spedometer arrangement.


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## EVDL List (Jul 27, 2007)

WE got vacuum. We could rig an old throttle boy to a fake intake
manifold and use the old vacuum dashpot. I was thinking of that but I
hate the fact that my vacumm pump comes on as much as it does. It is noisey


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