Sources for Small motors??
- Thread starter phenix
- Start date
You can get HVAC damper motors. They are 24VAC and only have 90 degrees of travel, but the torque is quite impressive up to 360 in/lbs. Check out belimo.us
--Bob
Thanks I'll check them out. I would like something that isn't limited to such a short range of travel.
Neurorad
Senior Member
Firgelli Automations sells motors, bost mostly linear actuators.
I have a list of additional suppliers at home, will post tonight - I know it includes Digikey and Parts Express.
I have a list of additional suppliers at home, will post tonight - I know it includes Digikey and Parts Express.
AnthonyZ
Active Member
http://www.surpluscenter.com/item.asp?UID=...amp;item=5-1587 The home haunter's staple...
Thanks for all the great sites.
I started thinking how to wire a reversible motor through a relay and I just can't figure out how to do it. It's easy to wire it through the relay to turn one direction but if you try and wire it for both directions it will short itself out. Right?? Am I correct in that??? It gets confusing after a while. My brain is starting to hurt. How about this? How would you guys wire a reversible motor through a relay or set of relays?
I started thinking how to wire a reversible motor through a relay and I just can't figure out how to do it. It's easy to wire it through the relay to turn one direction but if you try and wire it for both directions it will short itself out. Right?? Am I correct in that??? It gets confusing after a while. My brain is starting to hurt. How about this? How would you guys wire a reversible motor through a relay or set of relays?
Do you need to stop the motor at a specific point too?
I did a project a number of years ago where I designed a simple relay circuit that when contact closure was made, it drove a 12v motor in one direction until it hit a limit swith and stopped. When the contact closure turned off, it reversed directions until it hit another limit switch and stopped.
The motor was a power window motor from a car so the whole thing ran on a single 12v power supply. The window motor was quiet and powerful and only cost around 12 bucks.
I think I put the whole thing together for about $35 and it's still working today about 8 years later.
I did a project a number of years ago where I designed a simple relay circuit that when contact closure was made, it drove a 12v motor in one direction until it hit a limit swith and stopped. When the contact closure turned off, it reversed directions until it hit another limit switch and stopped.
The motor was a power window motor from a car so the whole thing ran on a single 12v power supply. The window motor was quiet and powerful and only cost around 12 bucks.
I think I put the whole thing together for about $35 and it's still working today about 8 years later.
mustangcoupe
Senior Member
There are ways to do it, but you want to be concerned with just reversing the polarity of motors the back EMF voltage could do some damage.
but you'd be looking for a DPDT relay to use
AnthonyZ
Active Member
http://www.internationalmeccanomen.org.uk/...orcontrol2a.htm Here's some easy schematics on using relays to reverse polarity.
AnthonyZ
Active Member
Here's an even easier one to figure out. http://i440.photobucket.com/albums/qq129/n.../4polerelay.jpg
also check out Jameco.com for small DC motors
here is two different ways to control the on/off and direction. The method on the left uses a double pole/double throw (DPDT)
to change the direction and a single pole relay to turn it on/off. The method on the right just uses two single pole/double throw (SPDT)
relays. If you turn one relay on the motor will run in one direction and if you turn the other relay on it will run the opposite. If you
turn them both on it won't do anything.
here is two different ways to control the on/off and direction. The method on the left uses a double pole/double throw (DPDT)
to change the direction and a single pole relay to turn it on/off. The method on the right just uses two single pole/double throw (SPDT)
relays. If you turn one relay on the motor will run in one direction and if you turn the other relay on it will run the opposite. If you
turn them both on it won't do anything.
Do some searching on "motor drivers" or H-bridges. These are designed to address the exact problem that you have identified, i.e. short circuits and reversing.
I just noticed that others posted using double-throw relays. Using that info and the searching I suggested should get an idea as to how to go about solving the problem.
gk
I just noticed that others posted using double-throw relays. Using that info and the searching I suggested should get an idea as to how to go about solving the problem.
gk
unless I am missing something, isn't the motor going to get to the limit, open the switch and then never be able to reverse?
I was cleaning out the basement and found a old Black and Decker Power screw driver. motor works great about 70 RPM. It simply reversed the polarity from the 3.6v battery contacts to reverse the motor. so using the battery that came with it as the power source would that DPDT Relay still work since it is 12v?
I'm new to playing around with these relays so sorry for the basic questions.
I'm new to playing around with these relays so sorry for the basic questions.
