Electric vehicle

[Lenny]

I would like to use a 12V automotive type starter motor to propel a
very small electric vehicle. This motor is unique in that there is no
Bendix drive on it, (its an old Ford starter), with just a shaft. I
realise that a series wound motor is probably not the best choice for
this application but I have the motor and would like to make use of
it. Initial torgue capability and of course control are both
concerns. The toal loaded weight of the conveyance will never exceed
300lbs. I don't know what kind of operating current to expect as I
can't really set this up without a controller of some sort for fear of
having the motor take off. I can only guess at perhaps 50 amps? I'm
sure some type of PWM controller is what I need but I'm not sure how
to implement this. Can anyone offer any suggestions or even better a
schematic? Thanks very much,
Lenny Stein, Barlen Electronics

 

[Pat Ford]

You are likely off by a factor of 10 for full load (500A is not unheard of )
Pat


"Lenny" <captainvideo462002@yahoo.com> wrote in message
news:d980bc2c.0405191026.294a41c6@posting.google.com...

I would like to use a 12V automotive type starter motor to propel a
very small electric vehicle. This motor is unique in that there is no
Bendix drive on it, (its an old Ford starter), with just a shaft. I
realise that a series wound motor is probably not the best choice for
this application but I have the motor and would like to make use of
it. Initial torgue capability and of course control are both
concerns. The toal loaded weight of the conveyance will never exceed
300lbs. I don't know what kind of operating current to expect as I
can't really set this up without a controller of some sort for fear of
having the motor take off. I can only guess at perhaps 50 amps? I'm
sure some type of PWM controller is what I need but I'm not sure how
to implement this. Can anyone offer any suggestions or even better a
schematic? Thanks very much,
Lenny Stein, Barlen Electronics

 

[Julie]

Lenny wrote:

I would like to use a 12V automotive type starter motor to propel a
very small electric vehicle. This motor is unique in that there is no
Bendix drive on it, (its an old Ford starter), with just a shaft. I
realise that a series wound motor is probably not the best choice for
this application but I have the motor and would like to make use of
it. Initial torgue capability and of course control are both
concerns. The toal loaded weight of the conveyance will never exceed
300lbs. I don't know what kind of operating current to expect as I
can't really set this up without a controller of some sort for fear of
having the motor take off. I can only guess at perhaps 50 amps? I'm
sure some type of PWM controller is what I need but I'm not sure how
to implement this. Can anyone offer any suggestions or even better a
schematic? Thanks very much,
Lenny Stein, Barlen Electronics

In general, starter motors are _not_ intended for continuous operation. Unless
you have specifications for your particular motor to the contrary, I'd
recommend against using it for conveyance -- at the minimum, you run the risk
of burning up the motor, worse, burning up the vehicle and causing incidental
damage.

 

[Doug Goncz]

To soft start a starter motor add a negative thermal coefficient of resistance
component called an inrush current limiter in series with the motor lead. This
does about 60% of what a PWM controller will do. Take off, that is. It's not a
throttle.

To get an inrush current limiter, call

1-800-DIGI-KEY

I soft started the starter motor on my 1986 Derbi DS-50 moped this way and
found it would drive the vehicle a few feet. Mostly, it just was dramatic.

Then I did more. Search Google for MOEPED to read about it.



Yours,

Doug Goncz ( ftp://users.aol.com/DGoncz/ )

Read about my physics project at NVCC:
http://groups.google.com/groups?q=dgoncz&scoring=d plus
"bicycle", "fluorescent", "inverter", "flywheel", "ultracapacitor", etc.
in the search box

 

[Big John]

Hi Lenny,

I'd stay away from a starter motor for this type of application. As you
say a series motor is not the best choice. If you want to use surplus
automotive parts consider a heater blower motor. The older ones are usually
permanent magnet motors with a commutator and brushes. So the speed is
voltage dependent and the current is load dependent. IIRC some of the
larger ones can have a full load current of 50 Amps. They are also designed
for continuous duty - although some air flow through the motor is used for
cooling.

You can control them with a PWM controller, or at least a high wattage
series resistor.

Hope this helps,
Big John



"Lenny" <captainvideo462002@yahoo.com> wrote in message
news:d980bc2c.0405191026.294a41c6@posting.google.com...

I would like to use a 12V automotive type starter motor to propel a
very small electric vehicle. This motor is unique in that there is no
Bendix drive on it, (its an old Ford starter), with just a shaft. I
realise that a series wound motor is probably not the best choice for
this application but I have the motor and would like to make use of
it. Initial torgue capability and of course control are both
concerns. The toal loaded weight of the conveyance will never exceed
300lbs. I don't know what kind of operating current to expect as I
can't really set this up without a controller of some sort for fear of
having the motor take off. I can only guess at perhaps 50 amps? I'm
sure some type of PWM controller is what I need but I'm not sure how
to implement this. Can anyone offer any suggestions or even better a
schematic? Thanks very much,
Lenny Stein, Barlen Electronics

 

[TCS]

On Wed, 19 May 2004 17:49:05 -0400, Big John <johnengr@NOSPAM.netlabs.net> wrote:

Hi Lenny,

I'd stay away from a starter motor for this type of application. As you
say a series motor is not the best choice. If you want to use surplus
automotive parts consider a heater blower motor. The older ones are usually
permanent magnet motors with a commutator and brushes. So the speed is
voltage dependent and the current is load dependent. IIRC some of the
larger ones can have a full load current of 50 Amps. They are also designed
for continuous duty - although some air flow through the motor is used for
cooling.

WTF kind of heater blower are you talking about? 50 amps??!!! That's still
less than 2/3HP, but about 5-10 times larger than any automotive application
could ever require, unless you're talking about a vehicle the size of a
2000 sqft. house.

 

[Ken Smith]

In article <VoKdnQJ40ovrSjbdRVn-iQ@netlabs.net>,
Big John <johnengr@NOSPAM.netlabs.net> wrote:

Hi Lenny,

I'd stay away from a starter motor for this type of application. As you
say a series motor is not the best choice.

Up until lately series motors were always the motor of choice for traction
motors. They make the highest torque for a given size and spin up to high
RPMs when needed.


--
--
kensmith@rahul.net forging knowledge

 

[Big John]

Hi Ken,

What you say is true, of course, but the OP said the application was a
"very small electric vehicle". I'm concerned that a starter motor may have
too much power for a very small application. Also, series motors can
sometimes run away if they are lightly loaded - which can be dangerous (for
example if a drive wheel were lifted off the ground). The OP didn't go into
much detail, but I think he'd need both current control and speed limiting
to make his "small electric vehicle" work. This is not easy on a motor that
can draw 200 - 300 amps. Granted there are IGBT modules that can handle
that much current - but they're the size of a brick! And remember that
starter motors are not rated for continuous duty.

Big John


"Ken Smith" <kensmith@violet.rahul.net> wrote in message

Up until lately series motors were always the motor of choice for traction
motors. They make the highest torque for a given size and spin up to high
RPMs when needed.

 

[John Popelish]

Lenny wrote:

I would like to use a 12V automotive type starter motor to propel a
very small electric vehicle. This motor is unique in that there is no
Bendix drive on it, (its an old Ford starter), with just a shaft. I
realise that a series wound motor is probably not the best choice for
this application but I have the motor and would like to make use of
it. Initial torgue capability and of course control are both
concerns. The toal loaded weight of the conveyance will never exceed
300lbs. I don't know what kind of operating current to expect as I
can't really set this up without a controller of some sort for fear of
having the motor take off. I can only guess at perhaps 50 amps? I'm
sure some type of PWM controller is what I need but I'm not sure how
to implement this. Can anyone offer any suggestions or even better a
schematic? Thanks very much,
Lenny Stein, Barlen Electronics

You need a controller that allows you to control motor current in
relation to an accelerator pedal, and since series wound motors go
destructively when unloaded (as when a drive train failure occurs) you
also need an over speed trip. Here is an example of a commercial PWM
drive used on golf carts:
http://cafeelectric.com/curtis/curtisschematic.pdf

--
John Popelish

 

[Ken Smith]

In article <CIqdnc_JZfiGozHdRVn-sw@netlabs.net>,
Big John <johnengr@NOSPAM.netlabs.net> wrote:

Hi Ken,

What you say is true, of course, but the OP said the application was a
"very small electric vehicle".

Without knowing what "very small" really means we are mostly just guessing
about the size of things.

I'm concerned that a starter motor may have
too much power for a very small application.

Are you mad! You can never have TOO much power!

Also, series motors can
sometimes run away if they are lightly loaded - which can be dangerous (for
example if a drive wheel were lifted off the ground).

Danger smanger.

The OP didn't go into
much detail, but I think he'd need both current control and speed limiting
to make his "small electric vehicle" work.

Unless his goal is to have it take off like a rocket when the switch is
pushed and only work about 10 times. In that case what he needs is a 24V
battery, a 12V truck starter and a big starter relay.

This is not easy on a motor that
can draw 200 - 300 amps.

Look up Popular Electronic's article on the "lead wedge" electric car.
They used a spinning contactor PWM design. It works up to really high
currents with no semiconductors at all.


--
--
kensmith@rahul.net forging knowledge

 

[Julie]

Ken Smith wrote:

In article <CIqdnc_JZfiGozHdRVn-sw@netlabs.net>,
Big John <johnengr@NOSPAM.netlabs.net> wrote:
Hi Ken,

What you say is true, of course, but the OP said the application was a
"very small electric vehicle".

Without knowing what "very small" really means we are mostly just guessing
about the size of things.

You can do a lot better than guess if you read the OP:

"The toal loaded weight of the conveyance will never exceed
300lbs."

So, estimate the size of a small go-kart or a rascal/scooter. (120 lbs for the
conveyance, 180 for the load (person).)

 

[Big John]

"Ken Smith" <kensmith@violet.rahul.net> wrote in message
news:c8ig9v$dm3$1@blue.rahul.net...

SNIP

Are you mad! You can never have TOO much power!

Tell me Ken, are you related to Tim Taylor?

Also, series motors can
sometimes run away if they are lightly loaded - which can be dangerous
(for
example if a drive wheel were lifted off the ground).

Danger smanger.

The OP didn't go into
much detail, but I think he'd need both current control and speed
limiting
to make his "small electric vehicle" work.

Unless his goal is to have it take off like a rocket when the switch is
pushed and only work about 10 times. In that case what he needs is a 24V
battery, a 12V truck starter and a big starter relay.

 

[Ken Smith]

In article <LMOdnWG-WaHlZTHdRVn-hw@netlabs.net>,
Big John <johnengr@NOSPAM.netlabs.net> wrote:
[...]

Tell me Ken, are you related to Tim Taylor?

Not that I know of.


--
Ken (the tool man) Smith

--
--
kensmith@rahul.net forging knowledge

 

[Terry Given]

"Julie" <julie@nospam.com> wrote in message
news:40ACCA9A.3C06BC04@nospam.com...

Ken Smith wrote:

In article <CIqdnc_JZfiGozHdRVn-sw@netlabs.net>,
Big John <johnengr@NOSPAM.netlabs.net> wrote:
Hi Ken,

What you say is true, of course, but the OP said the application was
a
"very small electric vehicle".

Without knowing what "very small" really means we are mostly just
guessing
about the size of things.

You can do a lot better than guess if you read the OP:

"The toal loaded weight of the conveyance will never exceed
300lbs."

So, estimate the size of a small go-kart or a rascal/scooter. (120 lbs
for the
conveyance, 180 for the load (person).)

Read? pish tosh I say. I dont know what it means, but it feels kinda neat to
say it

cheers
Terry

 

[Terry Given]

"Big John" <johnengr@NOSPAM.netlabs.net> wrote in message
news:CIqdnc_JZfiGozHdRVn-sw@netlabs.net...

Hi Ken,

What you say is true, of course, but the OP said the application was a
"very small electric vehicle". I'm concerned that a starter motor may
have
too much power for a very small application. Also, series motors can
sometimes run away if they are lightly loaded - which can be dangerous
(for
example if a drive wheel were lifted off the ground). The OP didn't go
into
much detail, but I think he'd need both current control and speed limiting
to make his "small electric vehicle" work. This is not easy on a motor
that
can draw 200 - 300 amps. Granted there are IGBT modules that can handle
that much current - but they're the size of a brick! And remember that
starter motors are not rated for continuous duty.

Big John

Big John,

I have a big, clunky old Powerex (Bitsashitty/Mitsubishi) 1200V 600A
CM600HA-24 IGBT sitting in front of me. It is 110mm x 80mm x 35mm - thats a
bloody small brick!

A fun thing to do when drunk is rip the fan off a vacuum cleaner motor, and
fire it up - do it in a paddock, and stand well clear. it will spin faster
and faster, and eventually self-destruct with an impressive bang.

A fun thing to do with a petrol engine is drain all the oil out, and run it
full throttle. Nothing like as good as the vacuum cleaner motor. I went to a
beach party once where someone had pinched a Suzuki DR750Big, and did
exactly that. It ran for about 15-20 mins (about the thermal time constant),
before fucking itself with a hiss and a roar. I also puked on myself that
night. ah, the good old days....

A fun thing to do with a 200HP V-twin compressor is to drop the guts of a
valve onto the top of one of the pistons, which when it hits TDC shears off
the top half of the barrel, fires it through a corrugated iron wall, and
down the length of a factory populated with workers whose underpants rapidly
become shit-encrusted. As a teenager I worked in my dads compressor
workshop, and stripped down said compressor prior to it being repaired. wow.
I also did a fair chunk of the labouring to build a brick enclosure for the
repaired compressor, and we re-oriented it so if the fault ever occurred
again, the barrel wasnt aiming at the factory wall.

A fun thing to do with an elevator in a 14 story building (true story - read
it in an elevator technical journal, was writing s/w for elevators at the
time) is to have a team of mechanics in the lift room, and the lift at the
ground floor, then have a stupid apprentice cut the lift cables. Alas the
counterweight (sitting at the top) didnt have gravity brakes (i forget the
correct term) and fell down. It went so fast the lift motor polled (rotor
swells and binds to stator), ripped the motor from its mooring and swung it
around like a giant flail, before breaking the cable. The counterwieght made
such a bang when it hit the bottom that it buggered the foundation of the
building, which IIRC ended up being demolished. I wonder if they took that
out of the apprentice's wages? The mag showed photos of the lift room, it
looked like it had been hit with a missile, but all the guys up there
survived.

cheers
Terry

 

[Terry Given]

"Ken Smith" <kensmith@violet.rahul.net> wrote in message
news:c8j7r0$l1d$2@blue.rahul.net...

In article <LMOdnWG-WaHlZTHdRVn-hw@netlabs.net>,
Big John <johnengr@NOSPAM.netlabs.net> wrote:
[...]
Tell me Ken, are you related to Tim Taylor?

Not that I know of.


--
Ken (the tool man) Smith

--
--
kensmith@rahul.net forging knowledge

Actually, if your power electronics is grunty enough, you can twist the
shaft right off a motor. preferrably someone elses motor ;} Have the motor
run at full speed one way, then with 20-30x overcurrent demand an "instant"
reversal. stand co-linear with the machine axis, that way if/when it rips
itself free from its mounting bolts, it wont come get you.

I miss working with big drives - this 60W smps stuff is SOOOOOOO boring.

Terry

 

[Ken Smith]

In article <ajnrc.8063$XI4.296773@news.xtra.co.nz>,
Terry Given <the_domes@xtra.co.nz> wrote:
[....]

Actually, if your power electronics is grunty enough, you can twist the
shaft right off a motor. preferrably someone elses motor

Yes and split the case and stick the armature shaftwise into the ceiling
20 feet overhead. Large DC machines can be a lot of fun.



--
--
kensmith@rahul.net forging knowledge

 

[Jan Panteltje]

On a sunny day (Sat, 22 May 2004 01:16:07 -0700) it happened "Terry Given"
<the_domes@xtra.co.nz> wrote in <Penrc.8059$XI4.296499@news.xtra.co.nz>>

A fun thing to do with an elevator in a 14 story building (true story - read
it in an elevator technical journal, was writing s/w for elevators at the
time) is to have a team of mechanics in the lift room, and the lift at the
ground floor, then have a stupid apprentice cut the lift cables. Alas the
counterweight (sitting at the top) didnt have gravity brakes (i forget the
correct term) and fell down. It went so fast the lift motor polled (rotor
swells and binds to stator), ripped the motor from its mooring and swung it
around like a giant flail, before breaking the cable. The counterwieght made
such a bang when it hit the bottom that it buggered the foundation of the
building, which IIRC ended up being demolished. I wonder if they took that
out of the apprentice's wages? The mag showed photos of the lift room, it
looked like it had been hit with a missile, but all the guys up there
survived.

cheers
Terry
And doing things with a 747?

Q

 

[Terry Given]

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message
news:c8l7p8$1q5$1@news.epidc.co.kr...

On a sunny day (Sat, 22 May 2004 01:16:07 -0700) it happened "Terry Given"
the_domes@xtra.co.nz> wrote in <Penrc.8059$XI4.296499@news.xtra.co.nz
A fun thing to do with an elevator in a 14 story building (true story -
read
it in an elevator technical journal, was writing s/w for elevators at the
time) is to have a team of mechanics in the lift room, and the lift at
the
ground floor, then have a stupid apprentice cut the lift cables. Alas the
counterweight (sitting at the top) didnt have gravity brakes (i forget
the
correct term) and fell down. It went so fast the lift motor polled (rotor
swells and binds to stator), ripped the motor from its mooring and swung
it
around like a giant flail, before breaking the cable. The counterwieght
made
such a bang when it hit the bottom that it buggered the foundation of the
building, which IIRC ended up being demolished. I wonder if they took
that
out of the apprentice's wages? The mag showed photos of the lift room, it
looked like it had been hit with a missile, but all the guys up there
survived.

cheers
Terry
And doing things with a 747?
Q

Now THAT was impressive. Emotive considerations aside (of which there are
plenty), it was a brilliant example of thinking outside the square.
Terry