Constant current, variable speed motors
Constant current, variable speed motors
(OP)
I'm a big out of my specialty here, but vaguely remember something from my sophomore year that leads me to think that what I want is fairly simple and doable.
I want to run 2 DC motors in such a way that one assists the other in moving a liquid. the first motor gets a certain volume of liquid moving, the second motor speeds that liquid a bit more. I want one control to operate both motors (variable current or voltage input), and at a given current, I want each motor to find it's own speed based on the torque.
In this way, both motors could be the same size, neither one would wear out much sooner than the other one, and operation should be fairly smooth and vibration free.
What kind of motors, and how to wire them together? Low current draw, and the ability to accelerate the volume of material moved by adjustment of the input current or voltage. I think 36 or 48vdc would be what I need to use.
Thanks in advance.
I want to run 2 DC motors in such a way that one assists the other in moving a liquid. the first motor gets a certain volume of liquid moving, the second motor speeds that liquid a bit more. I want one control to operate both motors (variable current or voltage input), and at a given current, I want each motor to find it's own speed based on the torque.
In this way, both motors could be the same size, neither one would wear out much sooner than the other one, and operation should be fairly smooth and vibration free.
What kind of motors, and how to wire them together? Low current draw, and the ability to accelerate the volume of material moved by adjustment of the input current or voltage. I think 36 or 48vdc would be what I need to use.
Thanks in advance.





RE: Constant current, variable speed motors
Can you step back a little and describe, in layman terms, what your plant is supposed to do. Without assuming anything about constant current and so forth?
Gunnar Englund
www.gke.org
RE: Constant current, variable speed motors
Just off the top of my head, I THINK I remember an instructor talking about using series motors, with the rotors of the motors wired in series with each other. I think I would prefer a compound motor though, but I am not sure.
RE: Constant current, variable speed motors
I hardly get your point,
let me clarify:
1. do you mean two motors in tandem - driving a load together?
2. or you mean a closed loop control having a master unit (first motor) and a slave unit (2nd motor), that is; where the slave backs up the master unit for any change of flow.
RE: Constant current, variable speed motors
Reqmts:
Motors should speed up at a given input votage based on reduced load, or slow down based on high load. Current should remain constant.
Motors should be wired together so that each one operates at the same torque output (not speed)for a given input voltage.
RE: Constant current, variable speed motors
What you describe are two motors running off constant current sources with an upper voltage limit. As simple as that. Any dual power supply (or two single supplies) with adjustable current limit can be used together with suitable DC motors.
Your idea of putting the motors in series will save one power supply. But the speed of one motor will be dependent on the other. So if one is lightly loaded, it will speed up - and that will make the other motor slow down and vice versa. Is that, perhaps what you want to achieve?
Gunnar Englund
www.gke.org
RE: Constant current, variable speed motors