pmdc motor circuit
pmdc motor circuit
(OP)
I'm currently trying to design a circuit that will regulate the current/voltage go to and leavin an PMDC motor. A 24V PMDC motor turns a rotating cylinder and at certain points the motor then acts as a generator because the cylinder makes the motor run faster. So im trying to design a circuit that has some sort of a braking system. I only want to brake so keep the motor at a steady speed. Reverse current and voltage has burnt out many motors and power supplies and this circuit will hopefully fix the problem. i know i can use a controller but i just need a simple circuit with a zener and some other simple components......a simple voltage/current regulator......Thanks for all your help.....





RE: pmdc motor circuit
The simplest method would be to have a power op amp that can absorb current as well as supply it to maintain a constant voltage. Theoretically that will maintain a constant speed except for resistance losses. Things burning up is a component selection issue.
RE: pmdc motor circuit
With the given information you're not going to get a lot of meaningful responses.
Benta.
RE: pmdc motor circuit
Overcoming the angular momentum in the mass of the cylinder of your application makes your application just a little different. Maybe you could implement a standard unidirectional control but have a H-bridge such that when the PWM is off it connects the motor to a resistor to brake it.
RE: pmdc motor circuit
Plesae read FAQ240-1032
WEB: <http://geocities.com/nbucska/>
RE: pmdc motor circuit
1. You are better off with a DC servo amplifier. [Advanced Motion, Copley, etc.]. All you do is call them, get a model#, order it, and hook up [there are setpoint settings].
Many of these have built-in "regeneration" circuits that will handle your "generating" problem and also protect the motor from too much current.
2. If you must built your own, you might try looking at motor driver chips. Companies include: TI [Unitrode}, Allegromicrosystems, ST Thompson, International Rectifier, Hitachi, etc.
The thing to remember is that many of the motor driver
chips do only two quadrant driving which does not handle
regeneration very well. You want 4 quadrant capable operation. Using these drivers chips with MOSFETs can save you time and you don't need to write firmware.
3. Use a DSP or microcontroller, write your own firmware, use gate drivers, MOSFETs, current sensors. This is not trivial and requires knowledge and time. A lot of the companies that sell these ICs have pretty good application notes.