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relays for motor control .... — Parallax Forums

relays for motor control ....

ArchiverArchiver Posts: 46,084
edited 2003-07-25 16:07 in General Discussion
In a message dated 7/25/03 12:40:04 AM Eastern Daylight Time,
nestlerv@a... writes:

> The following link shows a the schematic for using the stamp to
> control motors. What kind of relays are these? I mean what ratings do
> i look for? Will the stamp crank out enough amps to through a relay?
>
> http://maelabs.ucsd.edu/mae_ds/stamp/how/hardware/motors_dpdt/dpdt.htm
> l
>
> Any help or links to these 10 pin relays that will work with the
> stamp will be greatly appreciated.
>
>

For some reason the link you gave wouldn't come up when I tried to go to it.
However, the size of the relay/motor contactor is based upon the current
used by the motor. Most motor starters (contactors / relays) are rated by
horsepower and amps.

Regarding the use of a stamp to drive the relay or contactor, you should use
a transistor to activate a D.C. relay then use the contacts of the D.C. relay
to activate any A.C. relays or motor contactors you may be using. Of course,
if the relay used for the motor control has a D.C. coil rated at the proper
voltage you can drive it directly off the transistor.

I hope this is some help to you.

Randy Abernathy
4626 Old Stilesboro Road
Acworth, GA 30101
Ph/Fax: 770-974-5295
E-mail: cnc002@a...

We do industrial woodworking machinery service, repair, and installaions.
Specializing in CNC machinery.


[noparse][[/noparse]Non-text portions of this message have been removed]

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-07-25 14:58
    Nestlerv,

    The relays shown are standard dual-pole, dual throw (DPDT) relays. Make sure
    that the relay coil is actuated by 5V, or you will need transistors to run
    the relay.

    Not shown in the schematic you linked are prorection diodes. These are
    critical, and failure to include them will ruin Stamp pins! When the
    magnetic field around the coil collapses (when it is de-enrgized) a large
    voltage spike is generated, much higher than the 5V a Stamp pin can take.
    You can use the very common 1N4004 or similar. Place the diode across the
    coil of the relay.

    The Stamp is not providing the power for the motors in this circuit, only
    the relay. So the Stamp doesn't have to "crank out" the amps for the motor.

    Jonathan

    www.madlabs.info

    Original Message
    From: "nestlerv" <nestlerv@a...>
    To: <basicstamps@yahoogroups.com>
    Sent: Thursday, July 24, 2003 9:39 PM
    Subject: [noparse][[/noparse]basicstamps] relays for motor control ....


    > The following link shows a the schematic for using the stamp to
    > control motors. What kind of relays are these? I mean what ratings do
    > i look for? Will the stamp crank out enough amps to through a relay?
    >
    > http://maelabs.ucsd.edu/mae_ds/stamp/how/hardware/motors_dpdt/dpdt.htm
    > l
    >
    > Any help or links to these 10 pin relays that will work with the
    > stamp will be greatly appreciated.
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-25 15:03
    Nestlerv,

    I forgot to mention that you should use a transistor to run the relay. The
    circuit you linked may work, but unless the relay has a VERY low current
    consumption, you will be stressing the Stamp pin, leading to pin burnout.
    The Stampworks PDF has schematics for this, and it is very important to do
    it this way. You can use any NPN switching transistor, like the ubiquitous
    2N2222.

    Hope this helps,

    Jonathan

    www.madlabs.info

    Original Message
    From: "nestlerv" <nestlerv@a...>
    To: <basicstamps@yahoogroups.com>
    Sent: Thursday, July 24, 2003 9:39 PM
    Subject: [noparse][[/noparse]basicstamps] relays for motor control ....


    > The following link shows a the schematic for using the stamp to
    > control motors. What kind of relays are these? I mean what ratings do
    > i look for? Will the stamp crank out enough amps to through a relay?
    >
    > http://maelabs.ucsd.edu/mae_ds/stamp/how/hardware/motors_dpdt/dpdt.htm
    > l
    >
    > Any help or links to these 10 pin relays that will work with the
    > stamp will be greatly appreciated.
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-25 15:54
    --- In basicstamps@yahoogroups.com, "Jonathan Peakall"
    <jpeakall@m...> wrote:
    > Nestlerv,
    >
    > I forgot to mention that you should use a transistor to run the
    relay. The
    > circuit you linked may work, but unless the relay has a VERY low
    current
    > consumption,


    using a darlington will offer both the diode and higher current to
    the coil.

    a 2003 has the diode and 7 channels. 2803 for 8 channels and these
    are well described in the archives.

    I think the TIP120, single channel darlington is the one with the
    internal diode if you want a single channel.

    Dave
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-25 16:07
    Nestlerv,
    If you want to control motors without using relays, check the schematics in
    http://www.geocities.com/jimforkin2003/ for some examples. You can turn on
    relays or do bi-directional control of motors, valves, lamps, solenoids,
    etc. using these methods and protect the stamp in the process against
    damage.

    jim


    Original Message
    From: Jonathan Peakall [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=q9KjHZCoEL_xvk4Y_sVv7UEPXtG9BBRRjF_JZl1mK2fISrINF-zJfi__S9P_dH4cdo-8-Gqtk1kGXF8B]jpeakall@m...[/url
    Sent: Friday, July 25, 2003 10:04 AM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] relays for motor control ....


    Nestlerv,

    I forgot to mention that you should use a transistor to run the relay. The
    circuit you linked may work, but unless the relay has a VERY low current
    consumption, you will be stressing the Stamp pin, leading to pin burnout.
    The Stampworks PDF has schematics for this, and it is very important to do
    it this way. You can use any NPN switching transistor, like the ubiquitous
    2N2222.

    Hope this helps,

    Jonathan

    www.madlabs.info

    Original Message
    From: "nestlerv" <nestlerv@a...>
    To: <basicstamps@yahoogroups.com>
    Sent: Thursday, July 24, 2003 9:39 PM
    Subject: [noparse][[/noparse]basicstamps] relays for motor control ....


    > The following link shows a the schematic for using the stamp to
    > control motors. What kind of relays are these? I mean what ratings do
    > i look for? Will the stamp crank out enough amps to through a relay?
    >
    > http://maelabs.ucsd.edu/mae_ds/stamp/how/hardware/motors_dpdt/dpdt.htm
    > l
    >
    > Any help or links to these 10 pin relays that will work with the
    > stamp will be greatly appreciated.
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >


    To UNSUBSCRIBE, just send mail to:
    basicstamps-unsubscribe@yahoogroups.com
    from the same email address that you subscribed. Text in the Subject and
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