hall effect switch problems

SgtWookie

Joined Jul 17, 2007
22,230
A) You still haven't posted a schematic of your circuit, so we don't know where you're getting the 25v from.

B) Rather than using a pot to decrease current, consider moving the Hall-effect sensor along a tangental line opposite the direction of rotation. This will do two things:
1) Since the distance between the magnets and the Hall-effect sensor will increase, the on-time of your electromagnets will decrease; a form of PWM if you will.
2) As the Hall-effect sensor will trigger earlier, and turn off much earlier, there will be less pull on the rotating magnets.

I wouldn't want to get your motor spinning too quickly; your magnets could come unglued and propel themselves in a straight line with a good deal of force. Wear protective eyewear.
 

Thread Starter

jasonspinmaster

Joined Mar 1, 2008
57
my circuit is on page 10.
the resistor from supply to collector is a2.2k not a 4.7k as in the circuit picture.
i am getting my 20 to 25 volts from 4 x air coils, connected to a full wave bridge rectifiers to a volt meter. this coils are not connected to the tigger circuit
 

SgtWookie

Joined Jul 17, 2007
22,230
OK, if the coils are not connected to the other circuit, by trying to store the EMF you're generating by the magnets spinning by your coils, you will be placing a load on the motor. You'll wind up with a net loss due to the resistance in the wire and the rectifier bridge.
 

hgmjr

Joined Jan 28, 2005
9,027
sgtwookie's suggestion of a PWM scheme to manage your motor speed may be the most effective method for this function.

Do you have a schematic of the overall system? It is not totally clear how the one circuit you have post interconnects to the other components in your design.

hgmjr
 
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