# [EVDL] Advanced Timing speed/volts chart, best setting for daily driving



## EVDL List (Jul 27, 2007)

With any motor/voltage/load combination there will be a sweet spot for brush 
timing.

As an example, at 48 volts, my Citicar would go about 32 MPH on flat ground at 
neutral (factory) brush timing.

I advanced it to approximately 10 degrees (mechanical) advanced. The 
acceleration was slightly slower, top speed was about the same, and efficiency 
fell off from about 250 wh/mi to about 300 wh/mile. Not good in any respect.

I set the brush timing to about 5 degrees advanced. Acceleration is faster, top 
speed increased to 35 MPH, and efficiency increased from 250 wh/mile (neutral) 
to about 235 wh/mile. Better in all respects. I wonder if 4 or 6 degrees might 
be better, but there is only so much room to drill brush holder mounting holes!

The motor is a ~6.7" GE rated for 36 volts, but operated at 48.

Another thing to keep in mind as you advance timing - if you reverse the motor 
to back up (if you have direct drive) the motor will have retarded timing, which 
increases the chance of arcing when powering in reverse.


Tom Keenan


----- Original Message ----
From: Mark Hanson <[email protected]>
To: [email protected]
Sent: Tue, May 17, 2011 1:29:33 PM
Subject: [EVDL] Advanced Timing speed/volts chart, best setting for daily 
driving


Hi Folk's,

Is there a recommended advanced motor timing RPM's/volts chart? I found that my 
Prestolite on my 100Vdc car had the best starting acceleration & normal driving 
performance at a neutral setting, a 3k lb car www.evalbum.com/1273 . 


My electro-Metro had a 8" ADC at 120Vdc and my Electric Jeep (Geo Tracker) was 
also 120Vdc but with a 9". I didn't advance the timing but i spoke with an apps 
engineer today who said they ship the 8" 203-06-4001A with a 10 degree 
mechanical advance favoring the CCW direction (but that's different from 
electrical degrees but not sure by how much). 


I heard about 10 years ago that they were shipped neutral so not sure when the 
transition occurred (if my previous motors were advanced from the factory). If 
I apply 6-12V in CW & CCW direction and the speed is the same then the motor is 
timed neutral. I think it would go faster in the advanced direction. 


Is there also a chart on mechanical vs electrical degrees? I know if it were 
set to 90 degrees mechanically the motor wouldn't move, would that be 0 or 360 
electrically?

best regards,
mark 
www.reevadiy.org 
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## EVDL List (Jul 27, 2007)

>>>>I heard about 10 years ago that they were shipped neutral so not sure w=
hen the transition occurred (if my previous motors were advanced from the f=
actory). If I apply 6-12V in CW & CCW direction and the speed is the sam=
e then the motor is timed neutral. >>>>

Has it been that long .... The net gain motors that are gray where in
neutral with not advanced timing holes , I believe when the did the
advanced timing they started painting them red. I have drilled new
holes to advance the timing in some of the old gray motors . What I
made to make this easy was to take a small piece of metal about 2
inches long and drilled two holes ,one 5/16 and the other 2 sizes
smaller of a tape . I drilled them 3/4 of an inch apart which is
about 10 % . I then bolted the metal template to the neutral hole and
lined up the other in the center of the turret and drilled the new
advanced timing hole , then taped it . Buy using this template I got
all 4 holes exactly right ( I did this a few other ways and didn't end
up with the holes lining up exactly).


<<<<I think it would go faster in the advanced direction.>>>>

Yes that's a good way to test for advanced timing

>>>>Is there also a chart on mechanical vs electrical degrees? I know if=
it were set to 90 degrees mechanically the motor wouldn't move, would that=
be 0 or 360 electrically?>>>

I'm not sure about that but I figured that 9 x 3.14 and 10% of 360 was
about 1/36 , that's how I got the 3/4 of an inch ,



Steve Clunn


--
Tomorrows Ride TODAY !
Visit our shop web page at: www.Greenshedconversions.com

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## EVDL List (Jul 27, 2007)

There really is no chart for timing advance because it is a function of 
motor design, and changes between motors. You could have a chart for a 
particular motor, though.



> Tom Keenan wrote:
> > With any motor/voltage/load combination there will be a sweet spot for brush
> > timing.
> 
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> >CitiCars had neutral timing because they ran their motors in both
> directions at full current. Neutral is the best compromise in this
> ...


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## EVDL List (Jul 27, 2007)

If anyone is interested, I have photos of the damage that can be caused when
running a motor set for 10 degrees advanced in reverse. This was an
Advanced DC FB1-4001A running at 144V. I had to replace all the brushes and
the brush holder. Most of the brush springs and major parts of the brush
holder were melted.

There is definitely lots of arcing that can happen when the brush timing is
wrong. This problem definitely becomes more pronounced as you run higher
voltage and higher current.

Mike

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of Tom Keenan
> Sent: Wednesday, May 18, 2011 3:45 PM
> To: 'Electric Vehicle Discussion List'
> Subject: Re: [EVDL] Advanced Timing speed/volts chart, best setting for
daily
> driving
> 


> > Lee Hart wrote:
> >
> > >CitiCars had neutral timing because they ran their motors in both
> > directions at full current. Neutral is the best compromise in this
> ...


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## EVDL List (Jul 27, 2007)

BTW Tom,

FWIW, I have a hundred lbs or so of aircraft brushes laying around somewher=
e and I probably have the correct brushes for these Citicar motors, would h=
ave to hand match but I have found a lot of interchanges over the years. Mo=
re importantly, I remember seeing some of the brushes being marked for "Hig=
h Altitude" and being of different composition than their regular cousins. =
If you still have the old brushes take a couple pictures and the dimensions=
and I will keep an eye out for replacements and different compositions (wh=
en I find the brush inventory that is, LOL). If I have anything that will d=
o you any good I will be happy to send you a set. David Chapman.

PS, on the timing advance topic I recall once years ago while at Dennis Ber=
ube's shop looking at a welder generator he was working on that had movable=
brush rigging, he fired it up and we played with the advance while watchin=
g the brushes and it was very interesting seeing the arcing increase and de=
crease when moving them around the "sweet spot" for the rpm. No wonder the =
guy is a champion, pays attention to everything. Wish I had had my digital =
Nikon back then, could have taken a short movie to share. DC.


---------------------------------------------------------------------------=
--------------------------------------------------------------
Quoting Tom Keenan:


>I took before/after videos of the brushes under load, and did not notice a
>significant amount of arcing either at zero or at 5 degrees advance. Wi=
th a
>more powerful setup, arcing may be more of a problem. In my case,
>advancing the brushes provided a few percentage points of improvement, but
>it may be because the original voltage rating and bi-directional needs were
>a compromise as you state. I haven't noticed any particularly unusual b=
rush
>wear, but since CitiCars that are driven on a daily basis are relatively
>rare, I don't have any standard to gauge wear against. My brushes were =
new
>about four years ago, and they've worn off perhaps 20% of their original
>length (were about 1 1/4"; are now just over an inch long) in about 5,000
>miles.
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