Re: [EVDL] cooling my conversion - changing motor RPM!
Tonight was the first time that I smelled my motor,
after driving 15 mins mostly freeway (60MPH) and
immediately after arriving opening the hood (to see
if everything was OK) and though there were quite
warm components in the (EV100) controller, the smell
came from the motor which was warm but not really hot
to the touch. Since this motor is attached to an
automatic gearbox, my expectation is that:
1. The motor is being lugged. I watched the battery
amp meter closely while driving and I noticed that
all the driving at lower speeds has the battery amps
staying below 200A. Only when getting up to higher speed
(above 45 MPH) the battery amps start to climb and at
top speed of 60 MPH the pack delivers 300A at just under
110V. (more on that later) I need to connect an RPM
counter (or repurpose one of the unused meters in the dash)
but I expect that the motor never gets beyond 2500 RPM.
The truck is definitely lacking power, so I would really like
to either convert to manual (which is a lot of work) or get
a different Diff ratio, so the motor does reach higher RPM
by the time it reaches the truck's top speed, so the EV100
controller can close its bypass contactor and give full
battery voltage to the motor.
This is an 11" GE motor so it should have enough power
even at "only" 120V pack.
2. The motor (and especially the brushes) need forced
cooling. I looked better and found a 3" hose connecting
to the motor from the controller enclosure. This means
that I really need to put the lid on the controller and
insert the fuse for the fan that pushes air into the
controller enclosure and from there into the motor.
The power at 60MPH of 300A at 110V is too high when I
compare it to the 50A at 312V that my S10 used to take
at 55 MPH constant - the S10 was 4800 lbs while this Ford
Ranger is under 4400 lbs. I already pumped the tires to
40 PSI but I did not check their toe-in yet. Also, this
truck has not been running much in the past years, so
there may be a brake or bearing dragging, although the
truck rolls easily on level terrain.
Reason that the current is quite constant around 200A
for all the speeds below Freeway speed is due to the
automatic tranny keeping the motor speed rather constant
(probably around 1500 RPM) so the motor current
limit will cause low power into the motor, because
RPMs are low, so voltage is low so duty cycle is low
so even if the 200 battery amps are multiplied into
the 500A controller limit, the low voltage (40% duty
cycle turns 200A 110V into 500A 44V) causes the
acceleration to be very disappointing until higher
speeds are finally reached and the motor RPM climb,
so the duty cycle clims and the motor gets more power
and that is exactly what I am experiencing.
I do have the impression that the transmission is
locking (or at least it switches to the highest gear)
at Freeway speeds, so that seems to be OK although not
as efficient as a manual gearbox.
Acceleration from standstill is abysmal after the first
few feet, so that is another indication of the tranny
switching at the wrong points.
I do not think that a 1989 Ford Ranger tranny can be
reprogrammed to switch at higher RPMs but that would
probably be the best solution - keeping the tranny
continuously in "kickdown" mode (low gear to allow
the input to run higher RPM and deliver more power)
Before I dig into the (unknown to me) parts of this
truck - does anybody have experience with this and
can give advice?
Thanks!
Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: xxx@xxx.xxx Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203
-----Original Message-----
From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] On
Behalf Of Voltswagon
Sent: Wednesday, June 06, 2012 10:11 AM
To: xxx@xxx.xxx.edu
Subject: Re: [EVDL] cooling my conversion
That makes sense. My 40C difference was from the measured high in the
brushes. The motor case delta would be much smaller with the larger
mass, surface area, and natural air exposure.
Squirrels do have higher air-flow, but I felt mine was more than
adequate, wish I'd gone with the 3" instead. I think it's 150 CFM, not
that that means much.
The blower really just needs to not restrict the airflow while in low
gear.
That ensures that when stationary or in higher gear you are getting the
same level of cooling.
--
View this message in context:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/cooling-my-
conversion-tp4655375p4655454.html
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Nabble.com.
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|
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Tonight was the first time that I smelled my motor,
after driving 15 mins mostly freeway (60MPH) and
immediately after arriving opening the hood (to see
if everything was OK) and though there were quite
warm components in the (EV100) controller, the smell
came from the motor which was warm but not really hot
to the touch. Since this motor is attached to an
automatic gearbox, my expectation is that:
1. The motor is being lugged. I watched the battery
amp meter closely while driving and I noticed that
all the driving at lower speeds has the battery amps
staying below 200A. Only when getting up to higher speed
(above 45 MPH) the battery amps start to climb and at
top speed of 60 MPH the pack delivers 300A at just under
110V. (more on that later) I need to connect an RPM
counter (or repurpose one of the unused meters in the dash)
but I expect that the motor never gets beyond 2500 RPM.
The truck is definitely lacking power, so I would really like
to either convert to manual (which is a lot of work) or get
a different Diff ratio, so the motor does reach higher RPM
by the time it reaches the truck's top speed, so the EV100
controller can close its bypass contactor and give full
battery voltage to the motor.
This is an 11" GE motor so it should have enough power
even at "only" 120V pack.
2. The motor (and especially the brushes) need forced
cooling. I looked better and found a 3" hose connecting
to the motor from the controller enclosure. This means
that I really need to put the lid on the controller and
insert the fuse for the fan that pushes air into the
controller enclosure and from there into the motor.
The power at 60MPH of 300A at 110V is too high when I
compare it to the 50A at 312V that my S10 used to take
at 55 MPH constant - the S10 was 4800 lbs while this Ford
Ranger is under 4400 lbs. I already pumped the tires to
40 PSI but I did not check their toe-in yet. Also, this
truck has not been running much in the past years, so
there may be a brake or bearing dragging, although the
truck rolls easily on level terrain.
Reason that the current is quite constant around 200A
for all the speeds below Freeway speed is due to the
automatic tranny keeping the motor speed rather constant
(probably around 1500 RPM) so the motor current
limit will cause low power into the motor, because
RPMs are low, so voltage is low so duty cycle is low
so even if the 200 battery amps are multiplied into
the 500A controller limit, the low voltage (40% duty
cycle turns 200A 110V into 500A 44V) causes the
acceleration to be very disappointing until higher
speeds are finally reached and the motor RPM climb,
so the duty cycle clims and the motor gets more power
and that is exactly what I am experiencing.
I do have the impression that the transmission is
locking (or at least it switches to the highest gear)
at Freeway speeds, so that seems to be OK although not
as efficient as a manual gearbox.
Acceleration from standstill is abysmal after the first
few feet, so that is another indication of the tranny
switching at the wrong points.
I do not think that a 1989 Ford Ranger tranny can be
reprogrammed to switch at higher RPMs but that would
probably be the best solution - keeping the tranny
continuously in "kickdown" mode (low gear to allow
the input to run higher RPM and deliver more power)
Before I dig into the (unknown to me) parts of this
truck - does anybody have experience with this and
can give advice?
Thanks!
Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: xxx@xxx.xxx Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203
-----Original Message-----
From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] On
Behalf Of Voltswagon
Sent: Wednesday, June 06, 2012 10:11 AM
To: xxx@xxx.xxx.edu
Subject: Re: [EVDL] cooling my conversion
That makes sense. My 40C difference was from the measured high in the
brushes. The motor case delta would be much smaller with the larger
mass, surface area, and natural air exposure.
Squirrels do have higher air-flow, but I felt mine was more than
adequate, wish I'd gone with the 3" instead. I think it's 150 CFM, not
that that means much.
The blower really just needs to not restrict the airflow while in low
gear.
That ensures that when stationary or in higher gear you are getting the
same level of cooling.
--
View this message in context:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/cooling-my-
conversion-tp4655375p4655454.html
Sent from the Electric Vehicle Discussion List mailing list archive at
Nabble.com.
_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere. Thanks.
|
| REPLYING: address your message to xxx@xxx.xxx.edu only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
_______________________________________________
| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere. Thanks.
|
| REPLYING: address your message to xxx@xxx.xxx.edu only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev