CENTURY STABILIZER (OLD DESIGN)
Century stabilizers old designs contains 5 12volts relays with plenty transistors, one HEF4011 and two CD4069 all controlled or calibrated with fine variable resistor (10Kohms) 13 C4815 transistors on one board with 10ohms resistor used to biased (in series) with relays. Its relay has protruding terminals as shown below.
Each variables are connected to a high resistor of 220kohms, the resistor is used to limit the current from the transformer. This voltage is first rectified by an IN4007 Diode
A 12volts ac terminal is connected to the board from the transformer to the power board. IN5399 Diodes rectified the 12vac from the rectifier while the 1000uf/50v is used to smoothen the circuit 220uf/20v capacitor are connected across each relays to reduce excess triggering of the relays.
The transformer terminals are labeled P1 to P6, it has 7 terminals, six to the relay one to the board. The display has 4 leds, working, delay, turbo and protection.The working led is red, the delay led is yellow or green, and the turbo led is green, while the protection led is orange colour.
As soon as the stabilizer is powered with or without delay. It delays for about 5seconds before sending output voltage but when it is on delay it takes about 3 to 5 minutes before transferring or sending out voltage output.
I like this type of century stabilizer panel because it is easy to calibrate, after repairs.
What i dislike is that the panel is too complex and the relays are difficult to replace.
Click here for the modern century board and compare both.
Century remains the best stabilizer in Nigeria as at now.
For more info consult us, feel free to ask your question we give you the best info needed.
From the diagram above RL1 low AC volts i.e. voltage from the transformer tapings (131/161v) The 196volts terminal to RL2, 240volts terminal to RL3, 220volts terminal to RL4, while RL5 is used to switch the output.
Before each of the relay coils are 669A Transistor with 22Ω resistors connected in series to the relay as shown below.
5 transistors (669A) controlling the relays Q6 (D667), controls the 4 variable resistors, Q7(D667) powers the ICS (LM324), while Q8(D667) was also used to send some voltage (signal) to C1 (LM324) to assist in comparing the voltage.
The variables are all set at a maximum of 7.5v from Q6. Signal voltage lines are picked from RL5, RL4, RL3. This AC voltage is reduced by 220kΩ Resistor connected in series to the AC voltage line; this voltage is further rectified by some diodes (Half wave Rectifier) then to the ICS. The variable resistors are all 10kΩ, they help in adjusting volt or stabilizing the voltage output. The panel is very simple, just few components, its display consist also 4leds, 1 delay button and one turbo button.
Its transformers are labeled in voltages not P1 to P6 as used by old board panel.
The board is powered by a 13volts and two 11volts AC.