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Topic: Electrical Help for a Push-pull solenoid (Read 1 time) previous topic - next topic

Blu-Vector

Hi, i have a system with this kind of hitter :

http://www.adafruit.com/products/413

This hits a lever that should release a spring.

But it has not enough streanght to release the spring even adding some voltage.

So i build another system.



With few coil the system shoot really hard but generate a lot of heat. With more coil the system burned my npn transistor. Is there any kind of diod or "safe" to put in this system? Or i need a biggher transistor?

It's rated
60v , 8amp

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retrolefty

Quote
It's rated
60v , 8amp


That will take a transistor rated for such a load, but you didn't state what transistor number you used. A logic level N-channel mosfet would be a good choice. Also you should wire a diode across the solenoid's terminals, cathode wired to the +12v side of the solenoid.

Lefty

Blu-Vector

#2
Sep 17, 2013, 09:01 pm Last Edit: Sep 17, 2013, 09:03 pm by Blu-Vector Reason: 1
the npn transistor is the bdx53C. Thks for the advice.
Airsoft Video Projects: [url=http://arduino.cc/forum/index

retrolefty


the npn transistor is the bdx53C


That would be a very marginal transistor to use as it's max rated current is 8 amps and that would only be met with proper heat sinking. Find a transistor with higher ratings.

Lefty

dc42


the npn transistor is the bdx53C


Darlington transistors like that one are #4 in my list of things not to use. See http://miscsolutions.wordpress.com/2011/10/16/five-things-i-never-use-in-arduino-projects/ for why. Use a logic level N-channel power mosfet instead, it will run much cooler. And connect a flyback diode in parallel with the solenoid as Lefty says.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

Blu-Vector



the npn transistor is the bdx53C


Darlington transistors like that one are #4 in my list of things not to use. See http://miscsolutions.wordpress.com/2011/10/16/five-things-i-never-use-in-arduino-projects/ for why. Use a logic level N-channel power mosfet instead, it will run much cooler. And connect a flyback diode in parallel with the solenoid as Lefty says.


Very interessing, i will try to use a IRF540N
Airsoft Video Projects: [url=http://arduino.cc/forum/index

retrolefty




the npn transistor is the bdx53C


Darlington transistors like that one are #4 in my list of things not to use. See http://miscsolutions.wordpress.com/2011/10/16/five-things-i-never-use-in-arduino-projects/ for why. Use a logic level N-channel power mosfet instead, it will run much cooler. And connect a flyback diode in parallel with the solenoid as Lefty says.


Very interessing, i will try to use a IRF540N


Not a good choice as it's not a 'logic level' mosfet and thus can't work to it's full rated values with a 5vdc gate voltage applied which is all an arduino output pin can apply.

Lefty

Blu-Vector

Waht about this, is rated 30v , 25amp , logic level P channel.
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TomGeorge

Hi, how often does the hitter have to operate and how long are you pulsing it to make it operate.
Tom... :)
Everything runs on smoke, let the smoke out, it stops running......VK3DMK

jackrae

#9
Oct 09, 2013, 10:10 am Last Edit: Oct 09, 2013, 10:14 am by jackrae Reason: 1
Trigger systems like you've made which use high current solenoids invariably do not use what I'll describe as "constant" supply current.  Generally the power to drive the solenoid comes from a charged capacitor which is switched into the circuit via the transistor (or better still a FET).  This is termed "capacitor discharge" powering.  This provides short duration high current, after which the current tails off the virtually zero.  The system is frequently used by model train enthusiasts to trigger point switching.  However their mode of triggering won't directly suit your application.   you will need to include the triggering FET between the system output and your coil (in effect the point control switch referred to in the explanation text.

See :  http://www.talkingelectronics.com/projects/CDU-2/CDU-2.html

Note that this text refers to using AC but the system works with DC as well.

Blu-Vector

I know the method of capacitor discharge but i have a really small compartment to insert electronics, otherwise i really dont need all that pushing power. Thanks for the link.



Quote
Hi, how often does the hitter have to operate and how long are you pulsing it to make it operate.
Tom... smiley


It gives a really hard punch so i think just one hit it's far sufficient, btw to be sure i can operate the solenoid just twice or three time with a delay of 2 sec or more, just to be sure, also operating the solenoid with a too fast trigghering or a "long push"  will cause the solenoid to heat up , and we dont want this to happen  :)



What about this mosfet it would be fine?

Waht about this, is rated 30v , 25amp , logic level P channel. ( sorry the link was missing in the last post )

http://www.onsemi.com/pub_link/Collateral/NTD25P03L-D.PDF
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pwillard

It was recommended that you try:
Quote
Use a logic level N-channel power mosfet instead


What made you decide on P channel?  Your solution will become more complicated with that device.

cjdelphi

A p-channel aint so bad... inside your function

Void setstate(boolean state)
.....
     state != state;
     digitalWrite(pin,state);

Wiring is a little different though.

dc42


A p-channel aint so bad... inside your function

Void setstate(boolean state)
.....
    state != state;
    digitalWrite(pin,state);

Wiring is a little different though.


The OP is running the solenoid from +12V, therefore if he uses a P-channel mosfet then he will need to level-shift the gate signal. Using an N-channel logic level mosfet is simpler.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

cjdelphi



A p-channel aint so bad... inside your function

Void setstate(boolean state)
.....
    state != state;
    digitalWrite(pin,state);

Wiring is a little different though.


The OP is running the solenoid from +12V, therefore if he uses a P-channel mosfet then he will need to level-shift the gate signal. Using an N-channel logic level mosfet is simpler.


I was under the impression to switch on the P-channel, sinking it to gnd/LOW would switch it on?   Or the problem being switching it off!

Use an NPN transistor to switch the P-FET then?

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