LUMENIS VersaPulse PowerSuite - 4.2.4 Turn On

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4.2.4 Turn On
The following sections describe the sequence of events starting from the time the system circuit breaker is
turned on to the completion of the self-test routine after the keyswitch is set to the run position.
4.2.4.1 Circuit Breaker On, Keyswitch Off
The 24 VAC Interlock Transformer T2 is energized and supplies 24 VAC through F10, R13 and LED2, turning
on LED2. The 24 VAC is also applied through the E-STOP switch to R14, illuminating LED4 and the main
transformer thermostat to R15, illuminating LED5. If the key is left in the OFF position, current cannot flow
through SW2, preventing LED6 from illuminating.
4.2.4.2 Turn On Sequence
As the key is rotated passed the ON (center) position, current flows through SW2, R16 and LED6, illuminating
LED6. As the keyswitch continues to rotate to the START (right) position, SW1 closes, allowing current
(KEYSTART) to flow to the bridge rectifier BR1, the common contact of the Main Contactor Control Relay K2,
R17 and LED7, illuminating LED7.
The 24 VAC is converted to a full-wave rectified signal by BR1 and becomes the input to the +12 VDC voltage
regulator VR1, rapidly charging C6 to +12 VDC (C+12V) with respect to C-. The C+12V becomes the supply
voltage to the following to the following loads:
• The coil of the Main Contactor Control relay K2.
• The softstart relay K1.
Initially C5 is discharged and Q1 turns on energizing K1 for 200ms (LED1 illuminates) directing the mains
current through the softsart resistors R1 & R2, K1 relay contacts and the primary side of the Main Isolation
Transformer.
C4 begins to charge and after 100ms, Q2 turns on and provides a current path from C+12V through K2 and
LED3 to C-, energizing the Main Contactor Control relayK2 and illuminating LED3. As K2 turns on, the 24
VAC is directed through the Main Contactor Control relay K2 to the coil of the Main Contactor K4, closing the
Main Contactor. 24 VAC is also routed through the Main Contactor auxiliary contacts and directed to the CPU
Holding Relay K3 and to the HVPS Interlock Circuit on J47.
When C5 is fully charged, Q1 turns off which disengages the softstart resistors. With full current available to
the Main Isolation Transformer, the secondary loads turn on, which also turns on the LVPS. If the CPU is
functioning properly, it will close the K3 relay by way of the CPU interlock inputs on J44. With K4 and K3
energized, the 24 VAC loop is latched on.