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Author Topic: Relay for a Motor  (Read 2054 times)

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Offline krazykajun05Topic starter

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Relay for a Motor
« on: April 06, 2008, 09:54:13 AM »
I need a relay that will switch a small motor from forward, reverse, and off.  Any suggestions of where to find one? Thanks

Offline airman00

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Re: Relay for a Motor
« Reply #1 on: April 06, 2008, 10:16:03 AM »
what are the motor specs?


check out allelectronics.com


also, why are you using a relay and not an H bridge or motor driver
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Offline benji

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Re: Relay for a Motor
« Reply #2 on: April 06, 2008, 10:32:07 AM »
you dont need a relay unless you are dealing with a relative high voltage operating motor(above 25 volts).
and if you need one there are 2 types of relays, dc and ac
the dc operates at 24 volts and it can pass a relatively big current through it
the ac ones need ac voltage at its input to conduct

just google dc or ac relays and youll get big info about em
good ol' BeNNy

Offline airman00

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Re: Relay for a Motor
« Reply #3 on: April 06, 2008, 10:33:28 AM »
the dc operates at 24 volts and it can pass a relatively big current through it


there are many types of relays , many even rated @ 5V
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Offline benji

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Re: Relay for a Motor
« Reply #4 on: April 06, 2008, 10:37:02 AM »
Quote
there are many types of relays , many even rated @ 5V
thats a better one i guess if you dont need very big currents at the output
good ol' BeNNy

Offline airman00

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Re: Relay for a Motor
« Reply #5 on: April 06, 2008, 10:39:10 AM »
Quote
there are many types of relays , many even rated @ 5V
thats a better one i guess if you dont need very big currents at the output

yep

but relays have a limited amount of switching times , whereas H bridges last almost forever
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Offline benji

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Re: Relay for a Motor
« Reply #6 on: April 06, 2008, 10:47:42 AM »
relays have slower switching than transistors (bridges) too
good ol' BeNNy

Offline krazykajun05Topic starter

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Re: Relay for a Motor
« Reply #7 on: April 06, 2008, 03:13:36 PM »
Thanks for the info.  I am trying to control two motors, one for each set of tracks.  Therefore I can steer the robot by switching one track forward and the other reverse, like a small tank.  The motors are can be powered by 1.5-3V, 0.2 Amps.  Sounds like the H-brigde is the way to go.

Offline airman00

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Re: Relay for a Motor
« Reply #8 on: April 06, 2008, 04:00:31 PM »
Thanks for the info.  I am trying to control two motors, one for each set of tracks.  Therefore I can steer the robot by switching one track forward and the other reverse, like a small tank.  The motors are can be powered by 1.5-3V, 0.2 Amps.  Sounds like the H-brigde is the way to go.

I would suggest using the L293  chip

search google for details

we can help you out with it
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Offline Admin

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Re: Relay for a Motor
« Reply #9 on: April 14, 2008, 07:13:41 PM »
fyi, you can make H-bridges using relays. The old motor drivers back in the 90's used relays - I still own some too.

But obviously its much better using mosfets for an H-bridge . . .

 


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