12 Volt DC Motor Generator Problem
12 Volt DC Motor Generator Problem
(OP)
In my experimental project I require a low rpm dc generator to charge a bank of 12 volt storage batteries.
A rotating shaft alternates in direction with a full rotation of 180 degrees, and, the shaft speed is low. It is a high torque power device and with magnetic gearing, the rotational speed can be around 150 rpm.
Alternators for small autos, motorcycles require too high a rpm. In my research the literature suggests the use of higher voltage stepper motors as a generator. A commercial permanent magnet dc generator is also suggested.
Because the shaft alternates in direction I feel this may restrict my options.
I would appreciate any ideas on how I can generate the required 12 volt dc voltage.
A rotating shaft alternates in direction with a full rotation of 180 degrees, and, the shaft speed is low. It is a high torque power device and with magnetic gearing, the rotational speed can be around 150 rpm.
Alternators for small autos, motorcycles require too high a rpm. In my research the literature suggests the use of higher voltage stepper motors as a generator. A commercial permanent magnet dc generator is also suggested.
Because the shaft alternates in direction I feel this may restrict my options.
I would appreciate any ideas on how I can generate the required 12 volt dc voltage.





RE: 12 Volt DC Motor Generator Problem
Use a drive belt and a one way clutch to drive the gearbox. Use a second crossed drive belt and one way clutch to also drive the gearbox so that no matter what direction the input shaft is turning, the gearbox and the generator always turn in the same direction.
Use your back to back drives as a first step when velocities are low. That saves you from the waste of accelerating and decelerating inertias at higher speeds. A flywheel may help but if it is to large, something will break.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 12 Volt DC Motor Generator Problem
The use of a commercial permanent magnet generator designed for low rpm's with 12 volt dc output or above would probably be the best choice. These are available from several sources but, the one drawback is the cost!
Thanks for your reply.