Need DC motor for 1963 Schwinn World Traveler

My name is David Lunde. I am looking for a motor that, in a thus far
fruitless attempt, I have been unable to find. PLEASE TAKE THE TIME
TO READ THIS, AND ANY SUGGESTIONS ANYONE HAS WOULD BE MUCH
APPRECIATED.

Bio:
I am 16 years old and I love outboards, bikes, cars and anything that
moves. I wanted to embark on a project that would be cool and overall
silent - meaning I wanted to make something electric. So here is what
I started...

My project:
I have a 1963 Schwinn world traveler (it was my father's) and I want
to hook a DC motor to it. I did some calculations (thanks to my
physics class) and according to my calculations I produce about 2/3 hp
on my bike. Here are my numbers if anyone is interested. You can do
the calculations


THE CALCULATIONS:

1 hp = 33,000 ft*lbs/min

my ft*lbs/min = my weight (224lbs) * length of the peddle from
rotation axis to end of peddle (7 in. or .58ft) * number of times I
peddle in one minute (50 revolutions/min under uphill conditions and
at slowest speed, full weight on one foot) = 6,533 ft*lbs/min

The rear and front sprockets have a gear ratio of 3.06:1 which means I
am actually peddling with 19,991 ft*lbs/min

This then means that I produce about 19,991/33,000 = .65 or almost 2/3
hp (I don't know if this is realistic. I remember reading someplace
that humans are capable of producing 1/5 hp or so, but this is what I
got.

-I would like speed and power, so I decided on a 1 hp DC motor. This
would be more than enough for me, especially considering two special
features on this Schwinn bike. First of all, it has a transmission.
Meaning there is a 17 tooth sprocket sticking out of a cylinder.
Inside that cylinder are three different gears. Lowest gear just
engages the outside sprocket and 2nd and 3rd gear engage gears inside
the transmission. So if I get this thing working I would be able to
shift gears by disengaging the motor and shifting (pretty cool).
Second of all, (this isn't really a function of the bike but...) I can
gear down the sprocket so I would need less than 1 hp but I want
power. Mounting the motor and future 12VDC car battery holder will be
no problem. Procuring a motor is my problem.

My Project PROBLEM:
-I can't find a flippin' 1 hp 12VDC motor for less than $400!! I
don't have that money! My first thought of solving this problem was
to use a starter motor from a V8 engine. If it can turn a fly wheel
in winter I would hope it could push me up a hill. So I went to a
junk yard and found many starter motors, but the motors (or all the
ones I've seen) have the bendix and the motor cast as one piece of
aluminum. Because of this I can't remove the bendix for fear of there
being no bearings left for the motor (I believe the bearings are cast
into the aluminum). Not only that, but the starter motors are NOT
made to run continuously. If they heat up it can melt soldering,
casting and whatever else is near. So that ruled that out...
The great thing about finding it at a junk yard was it was cheap.

What I need:
I NEED A 1HP 12VDC MOTOR THAT WILL RUN CONTINUOUSLY FOR CHEAP. I am
not very rich. If there is an older style car that someone know about
where the bendix and motor are separate I would be willing to look at
that, but I would rather have a continuous running motor instead. So
if there are any suggestions, please please please e-mail me or
respond back to this. All would be much appreciated.


Thank you for reading this and for your time. There are a lot of good
brains to be picked on the Internet.

Any questions just e-mail me or respond to group. I will look daily
for responses.

Sincerely,
David Lunde

David,

I think what you are trying to do is really neat. Keep at it and you will come up
with something good. I hope my remarks will help you to achieve your ends.

You seem to be making a common mistake, confusing ft-lbs of energy with lb-ft of
torque, and they are not the same thing. In your first paragraph you correctly
come to the conclusion that if you could apply your entire weight to the pedals
tangentially over the entire circular pedal stroke, at 50 rpm, then you would
generate about 6500 ft-lb/ min of work. This is equivalent to about 0.2 HP.

You cannot then increase this (power) by the gear ratio, because changing the
speed does not increase the power developed. In fact with your 3.06 gear ratio,
the torque developed by the rear wheel actually goes down by the ratio, not up.
This is because the rear wheel turns faster than the chain ring, and the product
of the force times the distance turned must be the same for the chain ring and
the wheel (conservation of energy).

I suggest that if you can really generate 2/3 HP continuously, you should be out
riding with and teaching Lance Armstrong :^)). (Take this in the right way, I'm
trying to be humorous)

As I said in the second Paragraph here, if all the conditions are met then you
would be generating about 0.2 HP, however you cannot deliver the entire torque
throughout the entire rotation cycle because for half of the cycle the pedals are
going more back and forth than up and down. Thus the force is not tangent to the
chain ring, and not generating the maximum torque except at the point where the
pedal is horizontal and on the down stroke . Even when you consider that there
are one hundred down strokes per minute at a cadence of 50 rpm, I doubt that you
are actually putting out more than about 1/6 HP.

This is not necessarily bad though. As you found out, a 1 HP 12 volt motor (is
very expensive) and would discharge an automobile battery in less than an hour.
However, it appears that you really do not need a 1HP motor. I think a 1/4 to a
1/2 hp continuous duty motor would be adequate, assuming proper gearing. Remember
that even a 1/4 hp continuous duty motor can pull quite a bit more HP for short
durations like climbing short hills etc. Even a 1/4 hp continuous duty 12 volt
motor will be hard to find. Because of the low voltage, large currents must be
carried, and this results in an expensive motor. You might want to consider some
sort of invertor/transformer/nvertor to convert it to AC, raise the voltage, and
then reconvert it to DC. I would expect a 110 volt 1/4 hp motor would be cheap
and readily available. Perhaps some electrical engineer in the group can comment
on this type of a system.

Hope this Helps,
Ernie



CapriciousD wrote:

My name is David Lunde. I am looking for a motor that, in a thus far
fruitless attempt, I have been unable to find. PLEASE TAKE THE TIME
TO READ THIS, AND ANY SUGGESTIONS ANYONE HAS WOULD BE MUCH
APPRECIATED.

Bio:
I am 16 years old and I love outboards, bikes, cars and anything that
moves. I wanted to embark on a project that would be cool and overall
silent - meaning I wanted to make something electric. So here is what
I started...

My project:
I have a 1963 Schwinn world traveler (it was my father's) and I want
to hook a DC motor to it. I did some calculations (thanks to my
physics class) and according to my calculations I produce about 2/3 hp
on my bike. Here are my numbers if anyone is interested. You can do
the calculations

THE CALCULATIONS:

1 hp = 33,000 ft*lbs/min

my ft*lbs/min = my weight (224lbs) * length of the peddle from
rotation axis to end of peddle (7 in. or .58ft) * number of times I
peddle in one minute (50 revolutions/min under uphill conditions and
at slowest speed, full weight on one foot) = 6,533 ft*lbs/min

The rear and front sprockets have a gear ratio of 3.06:1 which means I
am actually peddling with 19,991 ft*lbs/min

This then means that I produce about 19,991/33,000 = .65 or almost 2/3
hp (I don't know if this is realistic. I remember reading someplace
that humans are capable of producing 1/5 hp or so, but this is what I
got.

-I would like speed and power, so I decided on a 1 hp DC motor. This
would be more than enough for me, especially considering two special
features on this Schwinn bike. First of all, it has a transmission.
Meaning there is a 17 tooth sprocket sticking out of a cylinder.
Inside that cylinder are three different gears. Lowest gear just
engages the outside sprocket and 2nd and 3rd gear engage gears inside
the transmission. So if I get this thing working I would be able to
shift gears by disengaging the motor and shifting (pretty cool).
Second of all, (this isn't really a function of the bike but...) I can
gear down the sprocket so I would need less than 1 hp but I want
power. Mounting the motor and future 12VDC car battery holder will be
no problem. Procuring a motor is my problem.

My Project PROBLEM:
-I can't find a flippin' 1 hp 12VDC motor for less than $400!! I
don't have that money! My first thought of solving this problem was
to use a starter motor from a V8 engine. If it can turn a fly wheel
in winter I would hope it could push me up a hill. So I went to a
junk yard and found many starter motors, but the motors (or all the
ones I've seen) have the bendix and the motor cast as one piece of
aluminum. Because of this I can't remove the bendix for fear of there
being no bearings left for the motor (I believe the bearings are cast
into the aluminum). Not only that, but the starter motors are NOT
made to run continuously. If they heat up it can melt soldering,
casting and whatever else is near. So that ruled that out...
The great thing about finding it at a junk yard was it was cheap.

What I need:
I NEED A 1HP 12VDC MOTOR THAT WILL RUN CONTINUOUSLY FOR CHEAP. I am
not very rich. If there is an older style car that someone know about
where the bendix and motor are separate I would be willing to look at
that, but I would rather have a continuous running motor instead. So
if there are any suggestions, please please please e-mail me or
respond back to this. All would be much appreciated.

Thank you for reading this and for your time. There are a lot of good
brains to be picked on the Internet.

Any questions just e-mail me or respond to group. I will look daily
for responses.

Sincerely,
David Lunde

David,

I think what you are trying to do is really neat. Keep at it and you will come up
with something good. I hope my remarks will help you to achieve your ends.

You seem to be making a common mistake, confusing ft-lbs of energy with lb-ft of
torque, and they are not the same thing. In your first paragraph you correctly
come to the conclusion that if you could apply your entire weight to the pedals
tangentially over the entire circular pedal stroke, at 50 rpm, then you would
generate about 6500 ft-lb/ min of work. This is equivalent to about 0.2 HP.

You cannot then increase this (power) by the gear ratio, because changing the
speed does not increase the power developed. In fact with your 3.06 gear ratio,
the torque developed by the rear wheel actually goes down by the ratio, not up.
This is because the rear wheel turns faster than the chain ring, and the product
of the force times the distance turned must be the same for the chain ring and
the wheel (conservation of energy).

I suggest that if you can really generate 2/3 HP continuously, you should be out
riding with and teaching Lance Armstrong :^)). (Take this in the right way, I'm
trying to be humorous)

As I said in the second Paragraph here, if all the conditions are met then you
would be generating about 0.2 HP, however you cannot deliver the entire torque
throughout the entire rotation cycle because for half of the cycle the pedals are
going more back and forth than up and down. Thus the force is not tangent to the
chain ring, and not generating the maximum torque except at the point where the
pedal is horizontal and on the down stroke . Even when you consider that there
are one hundred down strokes per minute at a cadence of 50 rpm, I doubt that you
are actually putting out more than about 1/6 HP.

This is not necessarily bad though. As you found out, a 1 HP 12 volt motor (is
very expensive) and would discharge an automobile battery in less than an hour.
However, it appears that you really do not need a 1HP motor. I think a 1/4 to a
1/2 hp continuous duty motor would be adequate, assuming proper gearing. Remember
that even a 1/4 hp continuous duty motor can pull quite a bit more HP for short
durations like climbing short hills etc. Even a 1/4 hp continuous duty 12 volt
motor will be hard to find. Because of the low voltage, large currents must be
carried, and this results in an expensive motor. You might want to consider some
sort of invertor/transformer/nvertor to convert it to AC, raise the voltage, and
then reconvert it to DC. I would expect a 110 volt 1/4 hp motor would be cheap
and readily available. Perhaps some electrical engineer in the group can comment
on this type of a system.

Hope this Helps,
Ernie



CapriciousD wrote:

My name is David Lunde. I am looking for a motor that, in a thus far
fruitless attempt, I have been unable to find. PLEASE TAKE THE TIME
TO READ THIS, AND ANY SUGGESTIONS ANYONE HAS WOULD BE MUCH
APPRECIATED.

Bio:
I am 16 years old and I love outboards, bikes, cars and anything that
moves. I wanted to embark on a project that would be cool and overall
silent - meaning I wanted to make something electric. So here is what
I started...

My project:
I have a 1963 Schwinn world traveler (it was my father's) and I want
to hook a DC motor to it. I did some calculations (thanks to my
physics class) and according to my calculations I produce about 2/3 hp
on my bike. Here are my numbers if anyone is interested. You can do
the calculations

THE CALCULATIONS:

1 hp = 33,000 ft*lbs/min

my ft*lbs/min = my weight (224lbs) * length of the peddle from
rotation axis to end of peddle (7 in. or .58ft) * number of times I
peddle in one minute (50 revolutions/min under uphill conditions and
at slowest speed, full weight on one foot) = 6,533 ft*lbs/min

The rear and front sprockets have a gear ratio of 3.06:1 which means I
am actually peddling with 19,991 ft*lbs/min

This then means that I produce about 19,991/33,000 = .65 or almost 2/3
hp (I don't know if this is realistic. I remember reading someplace
that humans are capable of producing 1/5 hp or so, but this is what I
got.

-I would like speed and power, so I decided on a 1 hp DC motor. This
would be more than enough for me, especially considering two special
features on this Schwinn bike. First of all, it has a transmission.
Meaning there is a 17 tooth sprocket sticking out of a cylinder.
Inside that cylinder are three different gears. Lowest gear just
engages the outside sprocket and 2nd and 3rd gear engage gears inside
the transmission. So if I get this thing working I would be able to
shift gears by disengaging the motor and shifting (pretty cool).
Second of all, (this isn't really a function of the bike but...) I can
gear down the sprocket so I would need less than 1 hp but I want
power. Mounting the motor and future 12VDC car battery holder will be
no problem. Procuring a motor is my problem.

My Project PROBLEM:
-I can't find a flippin' 1 hp 12VDC motor for less than $400!! I
don't have that money! My first thought of solving this problem was
to use a starter motor from a V8 engine. If it can turn a fly wheel
in winter I would hope it could push me up a hill. So I went to a
junk yard and found many starter motors, but the motors (or all the
ones I've seen) have the bendix and the motor cast as one piece of
aluminum. Because of this I can't remove the bendix for fear of there
being no bearings left for the motor (I believe the bearings are cast
into the aluminum). Not only that, but the starter motors are NOT
made to run continuously. If they heat up it can melt soldering,
casting and whatever else is near. So that ruled that out...
The great thing about finding it at a junk yard was it was cheap.

What I need:
I NEED A 1HP 12VDC MOTOR THAT WILL RUN CONTINUOUSLY FOR CHEAP. I am
not very rich. If there is an older style car that someone know about
where the bendix and motor are separate I would be willing to look at
that, but I would rather have a continuous running motor instead. So
if there are any suggestions, please please please e-mail me or
respond back to this. All would be much appreciated.

Thank you for reading this and for your time. There are a lot of good
brains to be picked on the Internet.

Any questions just e-mail me or respond to group. I will look daily
for responses.

Sincerely,
David Lunde

David,

I think what you are trying to do is really neat. Keep at it and you will come up
with something good. I hope my remarks will help you to achieve your ends.

You seem to be making a common mistake, confusing ft-lbs of energy with lb-ft of
torque, and they are not the same thing. In your first paragraph you correctly
come to the conclusion that if you could apply your entire weight to the pedals
tangentially over the entire circular pedal stroke, at 50 rpm, then you would
generate about 6500 ft-lb/ min of work. This is equivalent to about 0.2 HP.

You cannot then increase this (power) by the gear ratio, because changing the
speed does not increase the power developed. In fact with your 3.06 gear ratio,
the torque developed by the rear wheel actually goes down by the ratio, not up.
This is because the rear wheel turns faster than the chain ring, and the product
of the force times the distance turned must be the same for the chain ring and
the wheel (conservation of energy).

I suggest that if you can really generate 2/3 HP continuously, you should be out
riding with and teaching Lance Armstrong :^)). (Take this in the right way, I'm
trying to be humorous)

As I said in the second Paragraph here, if all the conditions are met then you
would be generating about 0.2 HP, however you cannot deliver the entire torque
throughout the entire rotation cycle because for half of the cycle the pedals are
going more back and forth than up and down. Thus the force is not tangent to the
chain ring, and not generating the maximum torque except at the point where the
pedal is horizontal and on the down stroke . Even when you consider that there
are one hundred down strokes per minute at a cadence of 50 rpm, I doubt that you
are actually putting out more than about 1/6 HP.

This is not necessarily bad though. As you found out, a 1 HP 12 volt motor (is
very expensive) and would discharge an automobile battery in less than an hour.
However, it appears that you really do not need a 1HP motor. I think a 1/4 to a
1/2 hp continuous duty motor would be adequate, assuming proper gearing. Remember
that even a 1/4 hp continuous duty motor can pull quite a bit more HP for short
durations like climbing short hills etc. Even a 1/4 hp continuous duty 12 volt
motor will be hard to find. Because of the low voltage, large currents must be
carried, and this results in an expensive motor. You might want to consider some
sort of invertor/transformer/nvertor to convert it to AC, raise the voltage, and
then reconvert it to DC. I would expect a 110 volt 1/4 hp motor would be cheap
and readily available. Perhaps some electrical engineer in the group can comment
on this type of a system.

Hope this Helps,
Ernie



CapriciousD wrote:

My name is David Lunde. I am looking for a motor that, in a thus far
fruitless attempt, I have been unable to find. PLEASE TAKE THE TIME
TO READ THIS, AND ANY SUGGESTIONS ANYONE HAS WOULD BE MUCH
APPRECIATED.

Bio:
I am 16 years old and I love outboards, bikes, cars and anything that
moves. I wanted to embark on a project that would be cool and overall
silent - meaning I wanted to make something electric. So here is what
I started...

My project:
I have a 1963 Schwinn world traveler (it was my father's) and I want
to hook a DC motor to it. I did some calculations (thanks to my
physics class) and according to my calculations I produce about 2/3 hp
on my bike. Here are my numbers if anyone is interested. You can do
the calculations

THE CALCULATIONS:

1 hp = 33,000 ft*lbs/min

my ft*lbs/min = my weight (224lbs) * length of the peddle from
rotation axis to end of peddle (7 in. or .58ft) * number of times I
peddle in one minute (50 revolutions/min under uphill conditions and
at slowest speed, full weight on one foot) = 6,533 ft*lbs/min

The rear and front sprockets have a gear ratio of 3.06:1 which means I
am actually peddling with 19,991 ft*lbs/min

This then means that I produce about 19,991/33,000 = .65 or almost 2/3
hp (I don't know if this is realistic. I remember reading someplace
that humans are capable of producing 1/5 hp or so, but this is what I
got.

-I would like speed and power, so I decided on a 1 hp DC motor. This
would be more than enough for me, especially considering two special
features on this Schwinn bike. First of all, it has a transmission.
Meaning there is a 17 tooth sprocket sticking out of a cylinder.
Inside that cylinder are three different gears. Lowest gear just
engages the outside sprocket and 2nd and 3rd gear engage gears inside
the transmission. So if I get this thing working I would be able to
shift gears by disengaging the motor and shifting (pretty cool).
Second of all, (this isn't really a function of the bike but...) I can
gear down the sprocket so I would need less than 1 hp but I want
power. Mounting the motor and future 12VDC car battery holder will be
no problem. Procuring a motor is my problem.

My Project PROBLEM:
-I can't find a flippin' 1 hp 12VDC motor for less than $400!! I
don't have that money! My first thought of solving this problem was
to use a starter motor from a V8 engine. If it can turn a fly wheel
in winter I would hope it could push me up a hill. So I went to a
junk yard and found many starter motors, but the motors (or all the
ones I've seen) have the bendix and the motor cast as one piece of
aluminum. Because of this I can't remove the bendix for fear of there
being no bearings left for the motor (I believe the bearings are cast
into the aluminum). Not only that, but the starter motors are NOT
made to run continuously. If they heat up it can melt soldering,
casting and whatever else is near. So that ruled that out...
The great thing about finding it at a junk yard was it was cheap.

What I need:
I NEED A 1HP 12VDC MOTOR THAT WILL RUN CONTINUOUSLY FOR CHEAP. I am
not very rich. If there is an older style car that someone know about
where the bendix and motor are separate I would be willing to look at
that, but I would rather have a continuous running motor instead. So
if there are any suggestions, please please please e-mail me or
respond back to this. All would be much appreciated.

Thank you for reading this and for your time. There are a lot of good
brains to be picked on the Internet.

Any questions just e-mail me or respond to group. I will look daily
for responses.

Sincerely,
David Lunde

"E. Willson" wrote: (clip) apply your entire weight to the pedals
tangentially over the entire circular pedal stroke,(clip)
^^^^^^^^^^^
Actually, I don't think that is what he said. If you stand on the pedal at
top dead center (out of the seat) and apply your weight until bottom dead
center, the work done equals the your weight x 2 x pedal arm length.
However, he used the pedal arm length, so he was off by a factor of two. I
get 224# x 14/12 ft x 50 RPM = 13066 ft lb/min, or .4 hp.

"E. Willson" wrote: (clip) apply your entire weight to the pedals
tangentially over the entire circular pedal stroke,(clip)
^^^^^^^^^^^
Actually, I don't think that is what he said. If you stand on the pedal at
top dead center (out of the seat) and apply your weight until bottom dead
center, the work done equals the your weight x 2 x pedal arm length.
However, he used the pedal arm length, so he was off by a factor of two. I
get 224# x 14/12 ft x 50 RPM = 13066 ft lb/min, or .4 hp.

"E. Willson" wrote: (clip) apply your entire weight to the pedals
tangentially over the entire circular pedal stroke,(clip)
^^^^^^^^^^^
Actually, I don't think that is what he said. If you stand on the pedal at
top dead center (out of the seat) and apply your weight until bottom dead
center, the work done equals the your weight x 2 x pedal arm length.
However, he used the pedal arm length, so he was off by a factor of two. I
get 224# x 14/12 ft x 50 RPM = 13066 ft lb/min, or .4 hp.

E. Willson wrote:

...
I suggest that if you can really generate 2/3 HP continuously, you should be out
riding with and teaching Lance Armstrong :^)). (Take this in the right way, I'm
trying to be humorous)....

2/3 HP (~500 W) average output would be a reasonable ballpark figure for
a top UCI professional rider during a medium length time trial.
--
Tom Sherman

E. Willson wrote:

...
I suggest that if you can really generate 2/3 HP continuously, you should be out
riding with and teaching Lance Armstrong :^)). (Take this in the right way, I'm
trying to be humorous)....

2/3 HP (~500 W) average output would be a reasonable ballpark figure for
a top UCI professional rider during a medium length time trial.
--
Tom Sherman

E. Willson wrote:

...
I suggest that if you can really generate 2/3 HP continuously, you should be out
riding with and teaching Lance Armstrong :^)). (Take this in the right way, I'm
trying to be humorous)....

2/3 HP (~500 W) average output would be a reasonable ballpark figure for
a top UCI professional rider during a medium length time trial.
--
Tom Sherman