Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: wkinne on March 29, 2009, 06:45:17 PM

Title: Help with wheelchair motor info please
Post by: wkinne on March 29, 2009, 06:45:17 PM
Can anyone give me some information on this motor please? It is an Everest & Jennings 24VDC Permanent Magnet Wheelchair motor. I believe they were made it the early 70's. What I need to know is RPM and current draw so I can select the proper size motor controller and gearing for my Robot. I will be using a 24VDC source. I know these were a very common motor and am hoping someone here has some data. CAD drawings would be awesome. Anything anyone one has would be great.

Thanks a lot
wkinne
Title: Re: Help with wheelchair motor info please
Post by: Soeren on March 29, 2009, 10:25:58 PM
Hi,

Did you try googling for some data?
Title: Re: Help with wheelchair motor info please
Post by: superchiku on March 30, 2009, 01:23:33 AM
really love the word "googling sounds so cute :D ;) :P
Title: Re: Help with wheelchair motor info please
Post by: wkinne on March 30, 2009, 08:53:36 AM
I have goggled till I'm blue in the face  :-[

wkinne
Title: Re: Help with wheelchair motor info please
Post by: ArcMan on March 30, 2009, 01:07:35 PM
Looks like you might have to do it the old-fashioned way.

Since you know the motor is 24VDC, you could connect it to your 24V battery source and measure the current and RPM unloaded and loaded.  One technique I've used to mechanically load gearmotors is:

Secure the motor to a fixture by bolts or clamp.  Attach something to the output shaft with some surface area (like a pulley or gear).  Use a piece of 2x4 lumber to apply some load to the face of the pulley or gear (without hurting yourself, of course).  If you do this, BE CAREFUL.  As I'm sure you know, these wheelchair motors have alot of torque.  You may be able to remove the gearbox from the motor to more easily load it.

Title: Re: Help with wheelchair motor info please
Post by: Symantic on March 30, 2009, 10:20:44 PM
Can anyone give me some information on this motor please? It is an Everest & Jennings 24VDC Permanent Magnet Wheelchair motor. I believe they were made it the early 70's. What I need to know is RPM and current draw so I can select the proper size motor controller and gearing for my Robot. I will be using a 24VDC source. I know these were a very common motor and am hoping someone here has some data. CAD drawings would be awesome. Anything anyone one has would be great.

Thanks a lot
wkinne
the current draw? meaning the amps its drawing?
well for the unloaded couldnt you stick a ohm meter on the coil of the motor and gets its resistance, then from there divide the resistance by the voltage (24) and then you get the amps, then if you want from there you can multiply the amps and the voltage together to get the watts.

Title: Re: Help with wheelchair motor info please
Post by: ArcMan on April 01, 2009, 08:37:36 PM
You're forgetting about back-emf.  The measurement you suggest would give the stall current.
Title: Re: Help with wheelchair motor info please
Post by: Admin on April 10, 2009, 01:01:37 AM
Quote
made it the early 70's. What I need to know is RPM and current draw so I can select the proper size motor controller and gearing for my Robot.
That thing is so rusted up that even if you were lucky enough to find a dry rotted paper datasheet, the specs will be so off from rust they'd be meaningless. :-X

Just power it up and take physical measurements to determine torque and rpm ;D
Title: Re: Help with wheelchair motor info please
Post by: wkinne on April 10, 2009, 06:02:47 AM
The motor is in new condition, I bought it new in 1981, I have 4 of them. They all run perfectly, I also have a wheelchair control box with joystick control. I know unloaded they draw 4 amps, but will blow a 15 amp controller the second you turn one on. And every one keeps saying to run one to see RPM, how do I do that without a meter?
Title: Re: Help with wheelchair motor info please
Post by: dellagd on April 11, 2009, 05:09:08 AM
get a stop watch, turn on the motors, and count how many 360 degree rotations there are in 1 minute.