how to have limit switches reverse motor direction

[Albm&ctd]

On Wed, 21 Apr 2004 08:39:12 +0100, Terry Pinnell
<terrypin@dial.pipex.com> wrote:

alb_mandctdNOWMD@connexus.net.au (Albm&ctd) wrote:

If the lifting and lowering distance isn't too great a simple crank
would do the job. No need then to reverse the motor direction.

For a few months I've been contemplating using that approach for a
possible Tea Accelerator. I would attach a clip to the tea bag and a
mono would raise and lower it for say 2 mins then alert me to
completion. Optimising rate of crank rotation would be important to
eliminate wave build up. Major downside might be motor noise. I was
wondering if a solenoid could be operated in silent mode by suitable
signal?

--
Maybe a wiper motor (with crank) and a bit longer string

We use pot bags with a dash of fresh peppermint.

Al
2004 insult page awaits your contribution
http://kwakakid.cjb.net/insult.html

 

[Dave Cole]

in article N9dA7kACq+gAFwY0@clara.co.uk, Syd Rumpo at sydrumpox@clarat.co.uk
wrote on 4/19/04 10:04:

In message <6b76deee507e996a65edcf754c600620@news.teranews.com>, krem
news@rkremser.endjunk.com> writes
Hello, I have a motor lifting an object over a set range. Upon reaching a
set height i would like it to reverse and then start to lower, and again
once reaching a bottom position change direction and begin to rase again. I
know i'm going to have to end up using limit switches and would prefer to
use two push button ones if possible.

Of course it's possible to use momentary switches, but you need some
form of memory as stated elsewhere. A single changeover toggle switch
with the appropriate mechanical linkages to switch it at the top and
bottom of travel might be a lot easier for you. Clunk at the top to
reverse the motor, and click at the bottom to initiate
unreversalization.
^^^^^^^^^^^^^^^^^

I like that Word. May I purloin it?
Dave Cole

 

[RoyalHeart]

Paul Hovnanian P.E. wrote:

krem wrote:

Hello, I have a motor lifting an object over a set range. Upon reaching a
set height i would like it to reverse and then start to lower, and again
once reaching a bottom position change direction and begin to rase again. I
know i'm going to have to end up using limit switches and would prefer to
use two push button ones if possible. (temperary on) The motor which needs
to be controlled is going to be running on either 5-6 volt dc supply and
doesn't pull a huge current. (typically runs on 4 AA batteries and lasts a
long time) I would like to have a solution which doesn't include and
microcontrollers as i've yet to take that plunge. Thanks in advance for any
input or suggestions


Operate the motor through a DPDT switch set up to reverse its direction.
Then, mount the switch itself (via a flexible cable) or a means of
flipping the switch between its two positions on the moveable object.

Two DPDT POPO (Push-On/Push-Off) switches. Each switch has the switched
contacts cross connected, then leg 'A' of each switch connected
together, and leg 'B' of each connected together. Power is applied
across the commons of one switch and the motor across the commons of the
other.

Anyone see a problem with this arrangement?

--

RoyalHeart

A thoughtful pause, then resumes the prince, "Thou hast to learn from
Yesterday, live for Today, and look forward to Tomorrow, for The Past is
The Present, and no less The Future."

 

[John Zobitz]

Greetings. I have a similar problem, except I am moving a cart
horizontally on a track, and the motor will be supplied by an AC (115
V) current. Would the same three pole double throw relay work, as
long as I have the correct load rating on the relay? Are there any
other considerations I need to think about when purchasing a relay (I
am a non-electrician). Can these be purchased at an electronics store
like Radio Shack or do they need to be purchased through a wholesaler?

Thank you very much.

John

RoyalHeart <royalheartREMOVE@barnwellscREMOVE.com> wrote in message news:<40902303.7030901@barnwellscREMOVE.com>...

Paul Hovnanian P.E. wrote:
krem wrote:

Hello, I have a motor lifting an object over a set range. Upon reaching a
set height i would like it to reverse and then start to lower, and again
once reaching a bottom position change direction and begin to rase again. I
know i'm going to have to end up using limit switches and would prefer to
use two push button ones if possible. (temperary on) The motor which needs
to be controlled is going to be running on either 5-6 volt dc supply and
doesn't pull a huge current. (typically runs on 4 AA batteries and lasts a
long time) I would like to have a solution which doesn't include and
microcontrollers as i've yet to take that plunge. Thanks in advance for any
input or suggestions


Operate the motor through a DPDT switch set up to reverse its direction.
Then, mount the switch itself (via a flexible cable) or a means of
flipping the switch between its two positions on the moveable object.


Two DPDT POPO (Push-On/Push-Off) switches. Each switch has the switched
contacts cross connected, then leg 'A' of each switch connected
together, and leg 'B' of each connected together. Power is applied
across the commons of one switch and the motor across the commons of the
other.

Anyone see a problem with this arrangement?

 

[John Popelish]

John Zobitz wrote:

Greetings. I have a similar problem, except I am moving a cart
horizontally on a track, and the motor will be supplied by an AC (115
V) current. Would the same three pole double throw relay work, as
long as I have the correct load rating on the relay? Are there any
other considerations I need to think about when purchasing a relay (I
am a non-electrician). Can these be purchased at an electronics store
like Radio Shack or do they need to be purchased through a wholesaler?

Thank you very much.

John

One big problem: Most AC motors will not change direction just
because you switch which winding the capacitor is in series with, once
they are turning. The cap just starts the motor in one direction or
the other. Only 3 phase motors can be plugged this way (reversed
while they are turning) and it is pretty hard on them.

--
John Popelish