Rapidly changing the polarity of a 55 volt DC Circuit

shortbus

Joined Sep 30, 2009
10,049
Why not use one of the many injector driver IC's? Then all that is needed is an oscillator the drive the IC, and a power supply. This is just one of the many drivers available.
 

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Dr.killjoy

Joined Apr 28, 2013
1,196
Just had a though and I not sure it can be done .. Why couldn't you take a diode and attach it to the magneto in order to get the 55v to open the injector..Then clean and flush the unit with cleaners cause that what most rebuilders do with injectors .. The other option is to take the magneto off and use a make shift flywheel with strong magnets to create the voltage to cycle the injector open and closed ..

Also check out
 

GopherT

Joined Nov 23, 2012
8,009
These injectors work as the motor is starting (20-30v) so 55V is not required, just better. Since 24 volts work, I propose using a full bridge 12 V sub-woofer playing an mp3 of a 10 to 30 Hz tone.
 

Dr.killjoy

Joined Apr 28, 2013
1,196
Why couldn't you just leave the injector in the motor and run the motor with high octane gas which has cleaner in it or pressurized the fuel system with cleaner as teh motor is running ??
 

GopherT

Joined Nov 23, 2012
8,009
Why couldn't you just leave the injector in the motor and run the motor with high octane gas which has cleaner in it or pressurized the fuel system with cleaner as teh motor is running ??
Because those detergents do not dissolve well into octane. Those detergents eventually for varnishes (polymer films) on the injectors. The solvents needed to dissolve the varnish will also swell rubber gaskets and o-rings. The idea of using an ultrasonic cleaner while the injector is pulsing is pretty good. Actually physically cleaning the part instead of solvating the crud.
 

dannyf

Joined Sep 13, 2015
2,197
Two approach:

1. Use ah bridge. Simple and can drive a low ohmic load. Or
2. Use an oscillator that outputs through a transformer with a center tap.
 

GopherT

Joined Nov 23, 2012
8,009
I see from this link that the injector has a moving-coil system with a spring return, so I don't think you need to reverse the pulse polarity.
The OP sent me a PM this morning. I suggested (and he happened to have) an old automotive Bridged Class-D audio amplifier that could drive a 2 ohm speaker. Since the coil in the injector is essentially a voice-coil as in a speaker, he drove it with a 10 - 30 hz signal (available from various you-tube "sub-woofer test tone" videos). It worked. He is now converting his big mess of cables to something a bit cleaner looking.

The injector works starting at about 20 volts during startup of the boat motor, the 24 volt p-p of the bridged output worked fine for a cleaning process.
 
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