Showing posts with label SCR regulator. Show all posts
Showing posts with label SCR regulator. Show all posts

Tuesday, October 20, 2015

Half Wave Stator to Full wave

We all know that small bikes charging system is made up of only a Half wave ac to dc conversion thus making it impossible for the system to give enough juice out from the stator to charge batteries at low rpm...To compensate for a FULL WAVE rectifier be installed on this system, we need to do some modifying to the stator,

the picture shown uses the stock configuration of a Half Wave system with an AC lighting coil present for headlight connection center tapped to the whole winding of the stator. One end of the coil is connected to chassis ground. I order for this system to give way for a FULL WAVE rectifier, the grounding system must be omitted and center tapped connection for headlight must be removed as shown on the next picture below.





the headlight will be redirected to the battery by cutting the yellow line of the AC lighting coil from the Stock regulator/rectifier, so that the headlight ON off switch as well as the HI/LOW system will still be used without any rewiring that headlight path.







ADVANTAGES of this system than the latter.

with full wave regulation you have almost twice usable dc power (and cleaner) than with half wave
last , cleaner regulation with the sens wire, if well used, it deliver more power if their is a drop (big consumption) than the other fixed simplier one where lighting often drop
and better protection for you electronic again drop or over charge
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Single phase voltage regulator (full wave)

Here is another voltage regulator for motorcycle design to be used on single phase stator.
This is the simplest full wave design commonly used on almost all commuter bikes  with 4 pin connector. Do not be mistaken with the half wave versions, for this one cannot be used on half wave stator design to which the other end of the windings is directly connected to ground. Again this is for a  FULL WAVE converted stator design and modifications.
By looking at the schematic, and comparing it to my previous post of voltage regulators, it is almost identical, with the design, and only component values are different. C1, R1, Q1, D1, and R3 compromising the sensing and regulating circuit, whereas D2,D3, Q2 and Q3 are the shunting components of the stator winding.


D4 to D7 are your rectifiers that converts the AC coming from the stator to DC for charging your battery. With the values as shown, the output of this regulator is 14.4 at 5000rpm. You can modify this circuit for your intended application, to output 15 volts rather than 14.4 for quick charging of your battery when there are too much load on your system, by altering D1, to 13 volts rather than 12.6 volts..
This system is Stator dependent...meaning, this can't output more power on what your stator can give, all charging system power rely on your stator max output...

Part list


R1= 3.3k ohms
R2= 1 k ohms
R3= 1.5k ohms
R4= 100 ohms
Q1= 2n5401
C1= 10uf / 25volts
D1= 12.6 volts zener / 1 watt
D2 /D3= 1n4007
SCR1 /SCR2= bt151-500 or bt151-600
D4-D7= bridge rated 100v 10A
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FULL WAVE regulator schematic

A full wave regulator is a type of regulator mostly found on small motorcycle that can enhance the charging system of motorcycle battery. It can be bought in a four pin or in a five pin configuration as shown on the left. It is also being used widely by enthusiast that convert their single phase half wave generator onto a full wave by altering the stator windings.

Wondering what is inside this kind of regulator and how it differs from those commonly used HALF wave regulator, you are in luck for i have the time and resources to open up this donor regulator. it took me hours of heating up, scraping the coating to expose the main board and parts.

Here it is.

with the help of a portable blow torch, soldering iron, a small flat screwdriver, and a bit of patience, I carefully removed the top coating of this regulator exposing the bottom of the PCB. and noticed the smd (surface mount devices). Seeing that makes me more careful of not scrapping them from their location.

Patience is the key when doing this kind of hobby.




















HOURS later,


Have to desolder first all components to pull out the pcb.














 The bridge rectifier that needs to be heatsinked.
 the epoxy residue..(too tough to scrape)
 top view
 side view

back view
















And the schematic of this board


By comparing this to my previous post

Single Phase Shunt Regulator (full wave)

They are almost identical, but as i have said, the regulator above is a five wire type, the schematic shown on left is a four pin type. The difference, the circuit within the link is always connected to the battery thus leakage is present. while as this regulator has a wire (BLACK) that is connected after the ignition switch and not directly to the battery.

It was used for one reason:

1. when ignition off, monitoring circuit of the schematic is disabled, no current will be taken from the battery when stored, or park.

We have a saying " its better to have more than to have enough" This particular five wire regulators can be used on four wire type. just connect the black and red together..

By looking at the schematic, and comparing it to my previous post of voltage regulators, it is almost identical, with the design, and only component values are different. C1, R1, Q1, D1, and R3 compromising the sensing and regulating circuit, whereas D2,D3, Q2 and Q3 are the shunting components of the stator winding.


D4 to D7 are your rectifiers that converts the AC coming from the stator to DC for charging your battery. With the values as shown, the output of this regulator is 14.4 at 5000rpm. You can modify this circuit for your intended application, to output 15 volts rather than 14.4 for quick charging of your battery when there are too much load on your system, by altering D1, to 13 volts rather than 12.6 volts..
This system is Stator dependent...meaning, this can't output more power on what your stator can give, all charging system power rely on your stator max output...


Note: further again..the generator to be used here do not touch the ground or not connected to any ground. 

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Motorcycle Voltage Regulator DIY




Introduction:
This project is a voltage regulator for a 3-phase, permanent-magnet alternator found on motorcycles. The same design can be used for single-phase alternators simply by eliminating some parts.  This project only describes the regulator, even though a rectifier is typically integrated into the unit.



Circuit Analysis:
Please refer to the circuit diagram during the analysis of the circuit.

Overview:
The way this type of regulator controls the alternator’s output voltage is by simply shorting out the stator winding for one cycle of the ac waveform. This is called shunting. This is done because it is much easier to short-circuit an inductor (the stator winding is an inductor) than to open-circuit an inductor. Very high voltages are induced when an inductor circuit is opened. This may cause a breakdown in the winding’s insulator.

The device used to shunt one cycle of one phase is an SCR. A silicon-controlled rectifier acts as a diode when triggered at its gate. It stops conducting when the current drops below a very low threshold value. Once it stops conducting, it will not conduct again until it receives another gate signal.

A voltage detection circuit is used to trigger the gate on each of the three SCRs. The threshold voltage to trigger the gate is selected as 14.6volt (on the motorcycle’s system-voltage). This is when the gate would trigger if there were no capacitor as described in the next paragraph.

Since the voltage from an alternator fluctuates, the detection circuit will trigger during a peak in the waveform of one of the phases, but this causes the average voltage to be too low. To raise the average system-voltage without increasing the detection threshold, a simple capacitor is used to delay the triggering of the SCR gates.  The capacitor acts as a filter to reduce the ac ripple going to the detection circuit. If the system voltage was strictly DC voltage (with no ripple) the gate would trigger at 14.6v and the average voltage would be 14.6v. In reality, the average voltage is always less than the threshold voltage and only approaches it as the ripple reduces. The actual trigger voltage is higher than 14.6v, but the average voltage is lower than 14.6v. As the ripple reduces, the average and trigger voltages approach 14.6v.
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Single phase shunt regulator again.

Motorcycle voltage regulator commonly uses shunt type in order to control the output of the generator. Shunting the winding to ground is easier than controlling the output of the regulator by those series type.

Circuit on the left is still a shunt regulator controlling the windings, with parts easily obtainable from your local electronic supply stores.



CIRCUIT DESCRIPTION:

D2 and D1 are the SCR that will control the voltage output of the generator, as the rpm of the engine rises D4 and D5 will convert the AC to DC and shall charge the battery, as the battery is being charged, it is been monitored by Q1, R1, D3 and R4 that comprises the voltage threshold of the entire unit and must be adjusted to 14.4 volts cut off. When the sense circuit seen the voltage rises, Q1 will be turned ON and current will then flow towards the gate of the two SCR turning them on thus shunting the windings not to generate more than needed, protecting the battery from overcharging.

NOTE that this circuit do not have a HEADLIGHT controlling device and or headlight regulator, its for charging battery only on motorcycles with stator.
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