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maintain initial and end position stepper motor without energy loss Answered

Hi all,

In a project of automated vertically folding curtain I have the problem that whatever the position of my curtain (8 kg) is, the motor is always drawing current. Let's say the curtain stays for 8 hours in the same position, then during these 8 hours the motor is wasting lots of energy.
Is there a method/mechanical system which can be used to make sure the motor only uses energy ("works") if the position of the curtain has to change?

Thanks in advance

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Downunder35m

3 years ago

Sure, it is called switching off when not use - works for lights in rooms with no people as well.

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Downunder35mDownunder35m

Reply 3 years ago

Sorry, I forgot: You fridge turns out the light automatically - it's like magic!
To try it out just empty the fridge, get in there and close the door - it will be dark.
So, if that works so well for every day household items like a fridge, maybe switching off could work for your motors too?

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KISELINDownunder35m

Reply 2 years ago

No. the light in your fridge doesn't turn off automatically, there is a mechanical switch to indicate this. Get an adventure and try to find this switch on yuor fridge and just "push it" to find out that the light in your fridge will turn off. MAGIC??

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mmsyxDownunder35m

Reply 3 years ago

Well that's the point, if I switch of the motors the curtain unrolls / falls down because I need the motor's holding torque to maintain the force on the ropes that pull on the curtain. So how to maintain the holding torque while the motor is turned off?

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steveastroukmmsyx

Reply 3 years ago

Isolate the motor mechanically with a worm gear box.

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Downunder35msteveastrouk

Reply 3 years ago

1+ "as is self locking"
But you see if this detail would have been included in the question...
Most curtain system use thin ropes or strings to move the curtain, you can also think of a "relay" to grab the rope when not in use - like these pull magnets you find in printers, some toasters, washing machine inlet valve and so on.
While the motor is on the relay is off and reverse.

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steveastroukDownunder35m

Reply 3 years ago

Good plan. You could use a real relay, and arrange the cord so that its locked in with a ratchet like action.

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KISELIN

2 years ago

Sure, there is a really simple solution check teksel.net