switching pole electromagnet project help

Thread Starter

Jason27

Joined Nov 15, 2015
32
hi everyone, would like ideas/help for a simple if possible 12v circuit that i can use to switch poles on my electromagnet for a demonstration electric motor. i don't know the amount of winds or wire size(looks like 2mm)has a resistance of 2.7 ohm's. i don't mind if it overheats a bit as I'm going to use it for short periods of time only. I've been using the electromagnet on a 12v 2.5amp,hr battery, but i need it to switch poles with variable speed control would be nice.
i have (if it helps) a few bc337,2n3055 and a mje3055 transistors handy.ill buy if needed of course.
appreciate the help.
 

Attachments

MikeML

Joined Oct 2, 2009
5,444
You need an H-bridge.

What signal causes the polarity to switch? Are you expecting to just use an asynchronous oscillator (multivibrator), or do you want to "commute" the motor by synchronizing the polarity switching with the shaft position?
 

Thread Starter

Jason27

Joined Nov 15, 2015
32
Hi MikeML
either would do as long as it spins, I'm guessing commute would be better? is that using a hall effect switch?if so i can only get the ugn3503u, op voltage 4.5-6vdc
current 9ma
output 2.5v
output res 50ohm's.
whats would you suggest?
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
Electronic commutation requires some kind of sensor to detect armature position together with switching circuit, the simplest way to commutate is using the DC motor method of using rotating coils that carry the contacts for the applied power, see bar commutator.
Max.
 

Thread Starter

Jason27

Joined Nov 15, 2015
32
thanks for replying guys, Richard i understand the principles of the motors I'm just not to good at making circuits, lol
i want to get away from brushed motors. as you can see in my first post there is a picture of the basic motor housing, it uses a single electromagnet. i wanted to obtain a circuit that will change polarity of the electromagnet when the hall sensor passes the magnet (desired but not a must). i have 2 of these electromagnets so i can also use one opposite sides of the motor. I'm using 12v and the only hall effect switch i can get is the ugn3503u, with a
op voltage 4.5-6vdc
current 9ma
output 2.5v
output res 50ohm's.
the diagram below is what i'm guessing i need but the hall sensor in this pic is a 12v unit and don't have the smarts yet to determine the modifications needed to use the 6v sensor.
i've also added a pic of a similar motor of what I'm trying to achieve.
tnx guys.82925-9706cdf3a939bda19db25c06b1967a08.jpg82924-bc429196dea9fbc80578a9220dcbaeb2.jpg
 

Thread Starter

Jason27

Joined Nov 15, 2015
32
You need an H-bridge.

What signal causes the polarity to switch? Are you expecting to just use an asynchronous oscillator (multivibrator), or do you want to "commute" the motor by synchronizing the polarity switching with the shaft position?
H-bridge worked perfect, tnx for the advice.
 
Top