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(Q) How to make a regulator/rectifier for automotive use?

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dirtydoogle

New Member
I have a dead reg/rec on one of my bikes and am thinking about building a new one.
Has anybody done this before?
To my knowledge the input to the reg/rec is 45V AC and is three phase, the output will ideally be 14.2-14.6V DC.
I have been reading about shunt resistors and bridge rectifiers, but, I am not so up with the play these days.
I can however get a cheap Reg/Rec for $15USD but as far as I am aware they utilise an SCR and are prone to overheating, I think also that is the same one that was already in the bike Voltage Regulator Rectifier Honda CH125 250cc 6 wires | eBay
Any ideas would be greatly appreciated.
 

RMMM

New Member
There have been some successful reverse-enginneering and re-building threads around the fourms, check google and the forum searches.

The ones I can think of are the "one wire" regulators.. So I have kuput to offer you on a 6 wire option.

For $15.40 and free shipping, it may be worth it to buy one or two and reverse engineer one. Post your findings for the rest of us, and maybe get some help making a more reliable version.

Actually, the heat sink would be worth the $15.
 
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KeepItSimpleStupid

Well-Known Member
Most Helpful Member
Probably the same as a car. Guessing:
2 for rotor access
2 for Batt and ground
1 for fault indicator
1 for +12 accessory power

Usually the rotor is pulsed. Harder part is the fault light. A PWM module can be purchsed as a kit for approx 25 USD. Now the other stuff would be harder but probably straightforward.
 

debe

Active Member
At $15 it would be easier & cheeper to buy. These regulators are just a rectifier unit & sink a load across the output to keep it from rising above 14V very crude regulator. If you want to improve on the design sugest you cut it opan & rev engineer it. They are nothing like car altenator regulators.
 

MikeMl

Well-Known Member
Most Helpful Member
The alternator uses a permanent magnet field, so the output is always max for any given rpm. Unlike with an automotive alternator, there is no way to modulate the field excitation; it is always full on.

The commercial regulators are a six-diode bridge rectifier to convert the three phase to dc, followed by a shunt regulator (wastes current by shunting it to ground). You can make it easier for the regulator by using the headlight as part of the current wasting circuit. (Headlight brightness is proportional to how much current needs to be wasted...)
 
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KeepItSimpleStupid

Well-Known Member
Most Helpful Member
The rotor is magnetized my the battery voltage. It's usually chopped.

Auto generators had a permanent magnetic field.

AC portable generators witout batteries act a bit differently. Residual magnatism kick starts the process.
 

Mr RB

Well-Known Member
The rotor is magnetized my the battery voltage. It's usually chopped.
...

Maybe in the 1970's.

Modern bikes almost universally use permanent magnet rotor and 3 phase or single phase stator.

The "Honda 6-wire regulator" usually has 3 AC input wires, Gnd, Bat+ and Ign+. It differs from a typical 5wire Japanese regulator in that it has the Ign+ wire, which means the regulator does not drain battery power when the Ign is turned off.

Typical 5 wire regulators have 3 AC input wires, Gnd and Bat+ wires and they draw a few mA from the battery at all times.

Just buy a cheap replacement regulator and connect the wires. :)
 
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