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Author Topic: optic sensor pulse motor  (Read 10406 times)

jasonspinmaster

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optic sensor pulse motor
« on: February 01, 2008, 08:53:35 PM »
i am building a pulse motor and i am using an optic sensor as the trigger. i am using a TIP 120 NPN Darlington transistor, from a 12 volt motor bike battery. i am getting a pulse but a small one. can any one help or does any one of any good but basic circuits. thanks all
jason compson

Groundloop

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Re: optic sensor pulse motor
« Reply #1 on: February 01, 2008, 09:35:27 PM »
@Jasonspinmaster,

Attached is a simple circuit that uses a Hall sensor. You can probably use a opto
coupler instead of the Hall device. It is also possible to put a diode bridge over L1 to
harvest back emf power.

Groundloop.

RunningBare

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Re: optic sensor pulse motor
« Reply #2 on: February 02, 2008, 12:15:12 AM »
i am building a pulse motor and i am using an optic sensor as the trigger. i am using a TIP 120 NPN Darlington transistor, from a 12 volt motor bike battery. i am getting a pulse but a small one. can any one help or does any one of any good but basic circuits. thanks all
jason compson

Need more information, whats the DC resistance of the coil?

hoptoad

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Re: optic sensor pulse motor
« Reply #3 on: February 02, 2008, 04:10:34 AM »
i am building a pulse motor and i am using an optic sensor as the trigger. i am using a TIP 120 NPN Darlington transistor, from a 12 volt motor bike battery. i am getting a pulse but a small one. can any one help or does any one of any good but basic circuits. thanks all
jason compson
@jasonspinmaster
Try this thread : http://www.overunity.com/index.php/topic,3318.0/topicseen.html

Cheers

jasonspinmaster

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Re: optic sensor pulse motor
« Reply #4 on: February 02, 2008, 12:25:29 PM »
the DC resistance of my coil is 003 ohms, i do not know if this sounds right or not. my coil is shaped like an ice cream cone, with a other wire wrapped around the primary coil for the back EMF (not connected )

jasonspinmaster

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Re: optic sensor pulse motor
« Reply #5 on: February 02, 2008, 01:59:18 PM »
sorry i made a mistake my coil resistance is 10 ohms.  thanks jason

RunningBare

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Re: optic sensor pulse motor
« Reply #6 on: February 02, 2008, 04:55:12 PM »
sorry i made a mistake my coil resistance is 10 ohms.  thanks jason

The maximum current the base of your TIP120 will see is 12/10000,  0.0012 amps, the TIP120 has a maximum current gain of 1000, that is the collector will load a maximum of 1000x0.0012 = 1.2 amps, with your coil only being 10 ohms its drawing the max, 12/10 = 1.2 amps.

You might want to increase the number of turns on the coil, say double, making it 20 ohms.

There are other ways, but I would need to know your exact configuration.

jasonspinmaster

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Re: optic sensor pulse motor
« Reply #7 on: February 02, 2008, 05:00:27 PM »
i can not get any more wire, as i do not have the money at the moment.
you say I would need to know your exact configuration
 what do you need to know and i will give you the information

RunningBare

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Re: optic sensor pulse motor
« Reply #8 on: February 02, 2008, 05:28:07 PM »
i can not get any more wire, as i do not have the money at the moment.
you say I would need to know your exact configuration
 what do you need to know and i will give you the information

Heres a couple of things you can try, I assume the diode connected to the emitter goes to ground or 0v line, if this is the case then it only serves to reduce gain by dropping about 0.6 volts across it, try bypassing it, secondly reduce the 10k resistor connected to the base to about half the value, the two closest value resistors I know of are 4.7k and 5.1k, you could start with a 6.8k and reduce further if needed, I do not know what your optical sensor is so I recommend you do not drop the resistance below 4.7k, reducing resistance will increase base current and thus collector current.

nickc44

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Re: optic sensor pulse motor
« Reply #9 on: February 02, 2008, 05:58:10 PM »
THis one should do but I'm looking for a way to bring the power back to the Power batters
to recharge

jasonspinmaster

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Re: optic sensor pulse motor
« Reply #10 on: February 02, 2008, 06:56:14 PM »
i have placed a 4.7k resistor instead of the 10k, and it is spinning a little faster.
my optic sensor is a OPB876 (N package)

jasonspinmaster

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Re: optic sensor pulse motor
« Reply #11 on: February 02, 2008, 07:13:34 PM »
 i do not understand you when you  said that i should try and bypass the diode from the emitter. how do i do this. if i just connect up i wire the transistor over heats, very fast

jasonspinmaster

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Re: optic sensor pulse motor
« Reply #12 on: February 02, 2008, 08:55:58 PM »
i have been able to drop the resistance down to a 2.2k resistor not the 4.7k
 the battery is at 10.25 volts
placing red pin of meter on base i am getting 0.99volts
from emitter 0.52
collector 12.25 volts

RunningBare

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Re: optic sensor pulse motor
« Reply #13 on: February 02, 2008, 09:57:10 PM »
i do not understand you when you  said that i should try and bypass the diode from the emitter. how do i do this. if i just connect up i wire the transistor over heats, very fast

Do you have a full diagram of the circuit, I need to know where the diode from the emitter goes?

jasonspinmaster

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Re: optic sensor pulse motor
« Reply #14 on: February 04, 2008, 03:48:07 PM »
the diode goes from emitter to negative in the battery