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latching pushbutton help

iKatoz

Nov 28, 2015
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Hi everyone,

I want to control a motor via four buttons, each button would run the motor at a predetermined speed. By pressing one of four buttons the engine starts, but I don't know how to detach the relay (supposedly) by pressing another button to change the speed of the motor.

I tried to draw a circuit diagram but I can't solve the problem, anyone can help me out?

Thanks
 
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Alec_t

Jul 7, 2015
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Welcome to EP!
What is the motor spec? AC? DC? Brushless? Voltage? Current? .....?
 

Tha fios agaibh

Aug 11, 2014
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Screenshot_2015-11-28-12-12-29-1.png Just use normally closed contact(s) to break relay(s)
You could wire all the nc contacts in series, so any button pressed would break the relay coils.
 

iKatoz

Nov 28, 2015
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Welcome to EP!
What is the motor spec? AC? DC? Brushless? Voltage? Current? .....?
Currently I don't know, I have an AC drill motor (500w) but I would buy a DC motor (24V) but I don't now if it's possible to slow down the motor to 50-200RPM (the range of the 4 buttons)

View attachment 23446 Just use normally closed contact(s) to break relay(s)
You could wire all the nc contacts in series, so any button pressed would break the relay coils.
Are you talking about latching relay or monostable relay?
 

iKatoz

Nov 28, 2015
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I think I confused the meaning of "latching" with "bistable". However I don't understand how to use the NC contacts for what I have to do
 

Minder

Apr 24, 2015
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If you are trying to reverse a ac drill motor they are usually Universal motors, the wound field is in series with the armature, the field has to be reversed with respect to the armature.
A DPDT SW with centre off will do it.
With these motors, usually triac control is used.
M.
 

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Tha fios agaibh

Aug 11, 2014
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The nc contacts are all in series, by pushing any button you kill power to one side of circuit.
Just use a separate relay contact to feed the motor at whatever speed you want to send to it.
 

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iKatoz

Nov 28, 2015
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I want also reverse the motor but I know how to do that part of the circuit.


I tried to draw a scheme but it's probably wrong
I use the second NO contact of the buttons to send an impulse to the activated relay but I don't know how the relay that i'm trying to activate might react
 

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Tha fios agaibh

Aug 11, 2014
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Actually I didn't understand everything

I forgot to ask,is there a monostable relay in multisim 11? can't find it
I Just drew simple relay logic that has a holding contact to latch relay coil power.
No monostable needed.
All you need is pushbuttons with seperate open and closed contacts. And a few relays with contacts heavy enough to handle motor current.

I don't know what multisim 11 is. ?
 

Minder

Apr 24, 2015
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By pressing one of four buttons the engine starts, but I don't know how to detach the relay (supposedly) by pressing another button to change the speed of the motor.
Thanks
That type of control or switching is called a 'Radio Button.'
It can be set up with relays, or there off the shelf ones.
Still no word on the type of motor??
Seems like Over-engineering going on.
M.
 

iKatoz

Nov 28, 2015
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That type of control or switching is called a 'Radio Button.'
It can be set up with relays, or there off the shelf ones.
Still no word on the type of motor??
Seems like Over-engineering going on.
M.
I can't find anything on the internet about this type of control
However, I think I'll open another thread specific for the motor but I think something like that would be fine http://it.rs-online.com/web/p/motori-cc/2483671/


I Just drew simple relay logic that has a holding contact to latch relay coil power.
No monostable needed.
All you need is pushbuttons with seperate open and closed contacts. And a few relays with contacts heavy enough to handle motor current.

I don't know what multisim 11 is. ?
it's a program to simulate circuits

However, is my scheme wrong?
 

Tha fios agaibh

Aug 11, 2014
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Old school, pencil and paper.
A little hard to follow on your drawing because your buttons look like relay contacts. Anyway, the speed selection is the easy part to do.
Your primary concern should be:
1, What type of motor am I using?
2, Is it capable of being slowing down?
3 How can this be accomplished?
What circuit is suited for this speed control?
 
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