Re: Brushed DC motor driver

On Mon, 05 Jan 2009 13:56:10 -0500, Spehro Pefhany
<speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Mon, 5 Jan 2009 10:32:57 -0800 (PST), lmcgill2 <lmcgill2@xxxxxxxxx>
wrote:

Hello all,
I have a 24VDC 1A brushed DC motor, but I have a 28V power supply. I
was wondering if I could use zener diodes to regulate the voltage down
to 24V. This seems doable until I consider changing the polarity to
switch the motor direction. Does anyone know of a creative design
that uses zeners that would allow me to still switch motor direction?

Any help would be great.. Thanks, Lucas.

You could put 4 diodes and a bridge in series with the motor:
(view with fixed-width font)

+---+
| |
.-----. | V
A -|~ +|---+ -
B -|~ -|---+ |
'-----' | |
| V
| -
| |
| |
| V
| -
| |
| |
| V
| -
+---+


Diode rating depends on the motor specifications (including stall
conditions).

Or put a zener (or a TL431) where you have the four diodes.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

If we knew what we were doing, it wouldn't be called research...
-- Albert Einstein
.

Relevant Pages

  • Re: Brushed DC motor driver
    ... I have a 24VDC 1A brushed DC motor, but I have a 28V power supply. ... that uses zeners that would allow me to still switch motor direction? ... You could put 4 diodes and a bridge in series with the motor: ... Or put a zener where you have the four diodes. ...
    (sci.electronics.design)
  • Re: Voltage regulator help!
    ... Do I just wire the three diodes in series inbetween the power ... You will actually get higher performance from the motor using the full 12v and limiting the current with big ... then you'll have to double that power dissipation. ... have to dissipate the heat either way, so I'd go for the extra performance. ...
    (sci.electronics.design)
  • Re: Converting Computer Power Supply to Variable Supply
    ... IMHO a good ole Variac and some ... spindle motor mounted on my BP.. ... Checkout this url for some pictures of the Variac and Diodes from hell.. ...
    (rec.crafts.metalworking)
  • Re: 555 Timer - less then 50% duty cycle question.
    ... >>duty cycle the diagram that the program displays has two diodes. ... >>In addition when switching a motor via the 555 what's the best choice ... >>both transistor and mosfet to switch a motor at approx 33% duty cycle ...
    (sci.electronics.basics)
  • Re: Driving Dual MOSFETs From A NPN Transistor
    ... your motor current will exceed the MOSFET rating. ... contactor with two N.O. contacts). ... If you place the honker diodes across the motor, ...
    (sci.electronics.basics)