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Old May 12, 2003, 09:07 AM
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Andycart's Avatar
West Yorkshire, UK
Joined Sep 2002
123 Posts
RFFS100 & 4mm pager motor

Hi Guys

I've been reading up on using 4mm pager motors for control surface actuators instead of the conventional coils and magnets.

Can I connect these directly to the coil outputs on the RFFS100 or will they draw too much current ?

If not, Graham do you stock the right type?

Andy
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Old May 12, 2003, 10:28 AM
Sticky Shepherd
Graham Stabler's Avatar
Oxford/England
Joined May 2001
4,017 Posts
The RFFS is rated for 50ohm (I think) so just add a resister in series to make the resistance up to 50.

Cheers,

Graham

p.s. Will have Didel actuators on my site soon
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Old May 12, 2003, 10:30 AM
Thats NOT indestructible
j8m8l's Avatar
London UK
Joined Apr 2002
1,448 Posts
ooh..

..didel actuators ! Do they come in 200ohm versions?

Josh
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Old May 12, 2003, 10:32 AM
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bselman's Avatar
sw missouri
Joined Sep 2001
389 Posts
Graham,

The RFFS-100 will drive 25 ohms.

Bob
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Old May 12, 2003, 10:36 AM
Sticky Shepherd
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Oxford/England
Joined May 2001
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Josh, not the ones I am stocking

Bob, Thanks.

Graham
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Old May 12, 2003, 10:42 AM
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dhurd's Avatar
Buffalo, New York
Joined Jan 2002
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The RFFS-100 is also limited to about 250ma so you will need to be careful if you stall the motor that it won't draw too much current.

Dan
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Old May 13, 2003, 04:49 AM
Sticky Shepherd
Graham Stabler's Avatar
Oxford/England
Joined May 2001
4,017 Posts
If it is 250mA per channel then it can drive 4.2v/0.25A = 16ohm.

Probably better to be safe and go for 25ohm though normally you cannot just measure the resistance of a motor and assume the current it will draw but in this case the motor will be stalled. Still, I would set it up as an actuator with some resistance in series to see what it draws then reduce or increase as nessecery.

Graham
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