Question about motors

Status
Not open for further replies.
A

amadeok

New Member
Hello,
I was thinkign about adding a motor to a bicycle, i these 2 kinds of motor:

Machifit 775 795 895 Motor/Motor Bracket DC 12V-24V 3000-12000RPM Motor Large Torque Gear Motor

Only US$7.99, buy best machifit 775 795 895 motor/motor bracket dc 12v-24v 3000-12000rpm motor large torque gear motor sale online store at wholesale price.
www.banggood.com
and
**broken link removed**

Here in italy it is mandatory for electric bicycles without insurance that their motor stops working after 25 km/h, and also the motor should not work if the rider is not pushing the pedals with his own strenght. So because of these reasons, i was wondering if those 2 motors would offer resistance when they are off, thereby making it actually harder for me to pedal when they are off?
thanks
 
amadeok said:
i was wondering if those 2 motors would offer resistance when they are off, thereby making it actually harder for me to pedal when they are off?
Click to expand...
There will inevitably be friction which will make pedalling a bit harder. If the motor is acting as a generator and significant current is drawn from it, then pedalling will be a lot harder.
 
alec_t said:
There will inevitably be friction which will make pedalling a bit harder. If the motor is acting as a generator and significant current is drawn from it, then pedalling will be a lot harder.
Click to expand...
I see thanks.
Do you know these type of motors? **broken link removed** different insertions have different specs, i don't know which are real , but the 895 at 24v should provide like 9 kgF/cm of torque, which i believe should be enough? Also there is the option for either 3000 - 6000rpm or 6000rpm-12000rpm. Would that make a difference?
 
alec_t said:
There will inevitably be friction which will make pedalling a bit harder. If the motor is acting as a generator and significant current is drawn from it, then pedalling will be a lot harder.
Click to expand...

But if there is a switch right at the motor to break the circuit to the battery or speed control, the resistance to pedaling would be a very minor thing. A complete ciruit is needed to make the BEMF as a generator.
 
I can't run the video, but I have doubts about the way the motors are mounted in the pic. I reckon they should be spring-biased towards the wheel to allow for wheel rim distortions and tyre sidewall deflection. If the bike frame tubes have a non-rectangulsr (e.g. oval) cross-section then I think it will be difficult to prevent the motor clamps slipping.
 
It looks like the Mickey Mouse way to destroy the bike tire needs a bike with a wheel that is not round.
I am amazed to see that they do unsafe things like that in India.
 
All motors will have friction and cogging torque.

The first is related to mechanical issues, mostly friction in the bearings.
The second is the normal attraction of the poles and magnets, as they rotate past each other.
 
schmitt trigger said:
All motors will have friction and cogging torque.

The first is related to mechanical issues, mostly friction in the bearings.
The second is the normal attraction of the poles and magnets, as they rotate past each other.
Click to expand...
I understand it's quite a bit offtopic but, do you think that if i attach somehow a freewheel(which has a latching mechanism inside) to the other side of the hub of the bike: (i marked in red)

and then connect that to a chain and the chain to the motor it will work?
This because i'm on a budget, replacing the whole wheel with a new double sided hub and can be expensive
 
Right now, I am watching my government talking about the Covid-19 virus and telling people:
1) Stay at home.
2) Work from your home or receive unemployment insurance pay while at home.
3) Shop online and have them deliver it to you.
4) Schools are closed so their school busses are not working then kids do not need to be outside spreading the virus around.
5) Use a treadmill at home for recreation and exercise instead of riding a bicycle outside.

Why do you ride a bicycle and why must it have a motor??
 
Speaking of the video;
it always amazes me the enormous ingenuity displayed in countries to obtain results with minimalist resources.

True, some ways may make Westerners cringe (hanging heavy Pb-acid batteries with tape), but got to give them credit.
 
I was also wondering if the "controller" was a simple rheostat to burn his hand as a speed controller or if it was simply a full-power or no-power switch.
Does the controller have a spring in it to disconnect the power when he releases the controller to activate the brakes?
 

Did you ever think that he is doing this while he is stuck at home? Not every country is as well off and rich as Canada.
 

That "latching mechanism" inside the freewheel is called a "one way bearing or a sprag clutch" To add one the the other side of the hub you would need to find one that locked up in the correct direction.

Does your pedal set have two sprockets? If you removed the front derailleur cable and locked it so it stayed on only one sprocket, that would then allow you to add a chain and sprocket to the motor. But you would need to lock out the front derailleur if doing this.
 
shortbus= said:
Not every country is as well off and rich as Canada.
Click to expand...
Few people in Canada play basketball or hockey on teams and get paid millions of dollars each year. Also, few people are doctors, lawyers and teachers.
Poor people here walk or ride a bus to work or take the school bus to school and back.
Nobody here dangerously attaches electric motors and batteries to an ordinary bicycle like in that horrible video from India.
 
audioguru said:
Poor people here walk or ride a bus to work or take the school bus to school and back.
Click to expand...
'Poor' people in Canada can easily afford to take the bus, vs those in other countries.
Poor people in developing countries might have to save for a month to be able to afford bus fare.....just for a one-way trip, or walk many miles just to get water.
People in developing countries have to make do with what they have, and in most cases it's far less than we, in the first world, would piss away on a cup of coffee at Tim Horton's, for example.
I would love to strip away your 1st world privileges, and make you live like the peasants you so despise for a few years.
You sicken me.
 
audioguru said:
Nobody here dangerously attaches electric motors and batteries to an ordinary bicycle like in that horrible video from India.
Click to expand...
AG you have obviously never visited India.

A bicycle with a home made motorising attachment is far from the worst vehicle that you will see on the roads.

On my working visits there, I saw worn out old trucks with bald, cut, perished tyres, lights hanging off and not working, belching out black smoke.
I don't know if there was an annual vehicle inspection programme, if there was the only mandatory item would have been a working horn.
As for the general standard of driving there, I am informed that there may be worse places in the world, but nobody would tell me where.

A few months ago I met up with a former colleague who had recently visited India for a holiday. He said that it was very good , far better than the places we visited while working.
All I can say is that from my experiences of the place, it is not on my holiday list.

As for motorising a bike, at the age of 14 or 15, I would have given it a go.
But if my father had found out, he would have given me hell for it.

Mickster said:
I would love to strip away your 1st world privileges, and make you live like the peasants you so despise for a few years.
Click to expand...
Mickster, if you find a magic lamp to rub which could make that happen, make sure that you get a video of it, I think that many people would like to see it.

JimB
 
The poorest people I have ever seen were in New York City slums. The resorts in Jamaica and Cuba were first class, I never went to see their slums.
I hear that India has a range of wealth. My eye surgeon and dentist are from India. Members of Canada's government are also from India.
Many people living in government welfare-paid townhouses in my city drive new Audi and BMW cars and drink expensive French cognac.

I am 74 years old with a fairly new car. But I still ride a bicycle and run around the park almost every day for exercise. It is a cheap bike and its tires are worn out but the tubes are full of sealer so they work fine. I don't want and don't need a motor on it because I am not disabled. My wife and I walk our dog fairly far every day even when it is very cold or very hot outside.
 
Status
Not open for further replies.

Similar threads

C
  • Question
am my steps about my question solution about bjt correct?
Replies
9
Views
4K
MrAl
M
C
  • Question
A small problem question about opamps
Replies
5
Views
2K
Tony Stewart
C
  • Question
a question I don't understand about the diode
Replies
7
Views
4K
Diver300
D
J
Tantalum Cap Question
Replies
2
Views
671
jb33
J
P
  • Question
Question about the circuit board
Replies
6
Views
3K
Tony Stewart
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…