Alternator question
I have appointment tomorrow to get new tires, about 6 miles total driving. I don't want to re-schedule appointment as I need m/h next Monday. But I'm waiting for elec part to come in. The part is...
Forum Discussion
Short Stop
Is
A
Ripoff
Buzzword for a Motorola type MR2535 avalanche diode, with a threshold of 28-32 volts. This gimmick caused a mini-sensation in the cruising sailboat world several years ago. At first the hucksters claimed that the "Short Stop" would minimize the effects of alternator "Load Dump" where the switch to the batteries was accidentally turned off while the alternator was charging hard. A dozen lawsuits later, the 3-card-monte business eliminated the claim from their ads.
Last month I purchased 100 MR2535 axial rectifiers from China or .22 each. That's twenty-two cents USA
But their intended use is to AUGMENT another (smaller) diode looking device called a "TVS" Transient Voltage Suppressor. The 200 TVS devices I purchased are rated for 16.0 volts DC. As a stop-gap buffering between the TVS voltage of 16.0 volts and the MR2535 voltage of 28-32 volts I chose to use a 20 mm Metal Oxide Varistor (MOV) rated 17 volts operational.
The alternator output stud is NOT the optimum place to mount a Transient Voltage Suppressor network (notice I wrote "network"). The converter output is a more rational choice to place a suppressor.
Your ENGINE air conditioner compressor clutch needs a suppression diode and it's easy to install. Not a special diode, a six amp or 10-amp regular silicon axial diode works fine. Determine WHICH of the two connections at the magnetic clutch is the + positive. The body of the diode has a distinct BAND at one end. For this purpose, orient the diode so the band faces (closest) to the + positive clutch terminal. Of course the opposite side of the diode gets connected to the - negative chassis ground, either at the remaining terminal or extended with a wire and hooked anywhere to a good - chassis ground negative.
This gets better...
Do exactly the same diode connection at the chassis engine starter motor. Same thing - the band of the diode is closest to the terminal. Do this for the small starter solenoid terminal, then do another diode for the starter motor positive power terminal.
Use heat shrink tubing to encapsulate the diode. It almost never sees an appreciable amount of current.
TECH STUFF: A collapsing field generates both POSITIVE and NEGATIVE transient voltage spikes. A wild-ass nine on the Richter Scale zig-zag voltage spike. By CLAMPING the Air Conditioner magnetic clutch, the engine starter motor, it's solenoid, the generator engine starter solenoid and it's starter motor, then placing a genuine transient voltage spike suppressor at the fuse/converter positive and negative busses, a genuine de-spiking network is created and both negative and positive transients get chopped off at the knees.
Such devices are a consumer hard-sell. This is why the makers of the MR2535 avalanche diode charge such a stupendous price for a diode, two wires, two terminals and swatch of heat shrink tubing.
The concept of "Just Pour Miracle Battery Additive XV-6 into the cells, and step on the starter!" is far from dead.
BTW the concept of AVALANCHE RECTIFIERS is valid. General Motors has been using them for decades as have been Mitsubishi, ND, and Hitachi. All six or eight power rectifiers in their alternators. They too are rated 28-32 volts.
You can do better than that. I just hope the swelling of seven or eight knuckles here has not been in vain.
Is
A
Ripoff
Buzzword for a Motorola type MR2535 avalanche diode, with a threshold of 28-32 volts. This gimmick caused a mini-sensation in the cruising sailboat world several years ago. At first the hucksters claimed that the "Short Stop" would minimize the effects of alternator "Load Dump" where the switch to the batteries was accidentally turned off while the alternator was charging hard. A dozen lawsuits later, the 3-card-monte business eliminated the claim from their ads.
Last month I purchased 100 MR2535 axial rectifiers from China or .22 each. That's twenty-two cents USA
But their intended use is to AUGMENT another (smaller) diode looking device called a "TVS" Transient Voltage Suppressor. The 200 TVS devices I purchased are rated for 16.0 volts DC. As a stop-gap buffering between the TVS voltage of 16.0 volts and the MR2535 voltage of 28-32 volts I chose to use a 20 mm Metal Oxide Varistor (MOV) rated 17 volts operational.
The alternator output stud is NOT the optimum place to mount a Transient Voltage Suppressor network (notice I wrote "network"). The converter output is a more rational choice to place a suppressor.
Your ENGINE air conditioner compressor clutch needs a suppression diode and it's easy to install. Not a special diode, a six amp or 10-amp regular silicon axial diode works fine. Determine WHICH of the two connections at the magnetic clutch is the + positive. The body of the diode has a distinct BAND at one end. For this purpose, orient the diode so the band faces (closest) to the + positive clutch terminal. Of course the opposite side of the diode gets connected to the - negative chassis ground, either at the remaining terminal or extended with a wire and hooked anywhere to a good - chassis ground negative.
This gets better...
Do exactly the same diode connection at the chassis engine starter motor. Same thing - the band of the diode is closest to the terminal. Do this for the small starter solenoid terminal, then do another diode for the starter motor positive power terminal.
Use heat shrink tubing to encapsulate the diode. It almost never sees an appreciable amount of current.
TECH STUFF: A collapsing field generates both POSITIVE and NEGATIVE transient voltage spikes. A wild-ass nine on the Richter Scale zig-zag voltage spike. By CLAMPING the Air Conditioner magnetic clutch, the engine starter motor, it's solenoid, the generator engine starter solenoid and it's starter motor, then placing a genuine transient voltage spike suppressor at the fuse/converter positive and negative busses, a genuine de-spiking network is created and both negative and positive transients get chopped off at the knees.
Such devices are a consumer hard-sell. This is why the makers of the MR2535 avalanche diode charge such a stupendous price for a diode, two wires, two terminals and swatch of heat shrink tubing.
The concept of "Just Pour Miracle Battery Additive XV-6 into the cells, and step on the starter!" is far from dead.
BTW the concept of AVALANCHE RECTIFIERS is valid. General Motors has been using them for decades as have been Mitsubishi, ND, and Hitachi. All six or eight power rectifiers in their alternators. They too are rated 28-32 volts.
You can do better than that. I just hope the swelling of seven or eight knuckles here has not been in vain.
