Forums | Home Repair | Home Improvement | Painting | Interior Decorating | Remodeling | Landscaping


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-20-2012, 04:05 PM   #1
Newbie
 
Join Date: Aug 2012
Posts: 3
Share |
Default

Dynamo Hub to power Solenoid Actuator Clutch


I'm designing a clutch for a pedal bicycle that will be engaged by the actuation of a solenoid linear actuator. The actuator is to recieve its power from a battery pack charged by one or two Dynamo hubs as the rider pedals.

My question, being a mechanical engineer, is what advice or comments would the electrical world have in terms of obstacles I may run into on such a project.

Thanks.

RookieAtThis is offline   Reply With Quote
Old 08-20-2012, 04:35 PM   #2
Member
 
Join Date: Jan 2012
Location: IL
Posts: 466
Default

Dynamo Hub to power Solenoid Actuator Clutch


Quote:
Originally Posted by RookieAtThis View Post
I'm designing a clutch for a pedal bicycle that will be engaged by the actuation of a solenoid linear actuator. The actuator is to recieve its power from a battery pack charged by one or two Dynamo hubs as the rider pedals.

My question, being a mechanical engineer, is what advice or comments would the electrical world have in terms of obstacles I may run into on such a project.

Thanks.

Be careful sizing the dynamo's. If you oversize them you'll put significant mechanical drag on the bicycle and make the rider waste a lot of energy just to charge a battery. Also the charging scheme for the battery is also of concern for the same reason.

You don't mention the travel distance required for the actuator to engage or disengage the clutch. A regular plunger solenoid will have limited travel and have high peak current. This is why automotive electric door locks don't actually use a solenoid, they use a gear reduced motor to drive up and down the lock mechanism, lower peak current, higher torque. Similarly dishwashers don't use solenoids to open up the soap dispensers. Instead they use wax motors which is a piston filled with wax. The wax is heated with a resistor and after a few seconds to minutes the wax softens and greatly expands in volume to provide a very strong piston force even with low power input. Both of these schemes achieve higher mechanical power with reduced peak power. They do it by spreading the energy across time, think of the area under the curve.

curiousB is offline   Reply With Quote
Old 08-20-2012, 05:02 PM   #3
Member
 
Oso954's Avatar
 
Join Date: Jun 2012
Location: Northern Calif.
Posts: 1,294
Default

Dynamo Hub to power Solenoid Actuator Clutch


What is the rest of the story ?
Clutches generally are not needed on pedal bicycles. Coaster gear hubs and coaster brake hubs work quite well. You don't need an electrical clutch, unless you are doing something quite different.
Oso954 is online now   Reply With Quote
The Following User Says Thank You to Oso954 For This Useful Post:
mpoulton (08-20-2012)
Old 08-20-2012, 05:26 PM   #4
Newbie
 
Join Date: Aug 2012
Posts: 3
Default

Dynamo Hub to power Solenoid Actuator Clutch


Great point Curious. I would like to be able attain reasonable torque maintained for a few seconds to keep the synchro/gear mating surfaces against the higher ratio stack until the lock engages, holdig it in place until the rider presses the unlock linkage level. The rest of the story is that the gearbox will allow the bike to achieve highway speeds with a single external chain.
RookieAtThis is offline   Reply With Quote
Old 08-21-2012, 08:32 AM   #5
Member
 
Join Date: Jan 2012
Location: IL
Posts: 466
Default

Dynamo Hub to power Solenoid Actuator Clutch


Quote:
Originally Posted by RookieAtThis View Post
The rest of the story is that the gearbox will allow the bike to achieve highway speeds with a single external chain.
At higher speeds doesn't the wind drag and mechanical losses of the rider/bike becomes larger than the energy the rider can deliver, even Lance Armstrong. If this weren't true then simply putting in high ratio gears would allow anyone to ride very fast....

It seems electrically actuating a clutch is the least of your concerns.
curiousB is offline   Reply With Quote
Old 08-21-2012, 09:04 AM   #6
Newbie
 
Join Date: Aug 2012
Posts: 3
Default

Dynamo Hub to power Solenoid Actuator Clutch


You're very right again, however speeds of 80-100km/h are nothing new on a bicycle. Any off the shelf bicycle can reach 60km/h down a 15 degree grade, the only question then becomes: are your off the shelf quick release axle pins under enough tension.
RookieAtThis is offline   Reply With Quote
Old 08-21-2012, 09:15 AM   #7
Member
 
Join Date: Jan 2012
Location: IL
Posts: 466
Default

Dynamo Hub to power Solenoid Actuator Clutch


Quote:
Originally Posted by RookieAtThis View Post
You're very right again, however speeds of 80-100km/h are nothing new on a bicycle. Any off the shelf bicycle can reach 60km/h down a 15 degree grade, the only question then becomes: are your off the shelf quick release axle pins under enough tension.

I think I'll stick to walking. Sounds safer...
curiousB is offline   Reply With Quote
Old 08-22-2012, 10:53 AM   #8
Newbie
 
Join Date: Feb 2012
Location: West Chester, PA
Posts: 19
Default

Dynamo Hub to power Solenoid Actuator Clutch


Quote:
Originally Posted by RookieAtThis View Post
You're very right again, however speeds of 80-100km/h are nothing new on a bicycle. Any off the shelf bicycle can reach 60km/h down a 15 degree grade, the only question then becomes: are your off the shelf quick release axle pins under enough tension.
I don't really have much to add here, but I am curious about your project. So you are planning to use the hubs to generate a charge for the battery and then the battery will drive an electric motor that will assist the rider like a pedal moped? It'll be interesting to see if you can produce enough power to sustain the speeds you're looking for. The gearing is there on your run of the mill road bike, it's just that most riders lack the power to get to those speeds - let alone sustain it.

Don't neglect the brakes... If you're able to achieve these speeds on the flats, you'll need a way to reliably stop you from 80-100km/h repeatedly. Heat will be an issue with normal bicycle hydraulic brakes and is a hurdle with regard to the current push for disc brakes on road bikes.

BShow is offline   Reply With Quote
Reply

Tags
bicycle, dynamo hub, generator, solenoid, solenoid actuator


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Event Production power distribution, I want to do it right. mattvivsound Electrical 0 07-13-2012 08:54 AM
Power strip hack salex Electrical 3 01-31-2012 06:10 AM
Recurring Power Oddities - Regular Schedule DamienChaos Electrical 16 10-21-2009 07:45 PM
Problem W/ Power after Switching Outlets... G19-Fanatic Electrical 17 08-28-2006 01:55 PM
Partial power on same fuse! joyjam Electrical 5 07-10-2005 10:23 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.