225 Exam Chair Back Up / Down Function Theory of Operation
|
Model |
225-002 and -003 |
| Serial Number | All |
This illustration shows only the components that affect the Back Up / Down function. Refer to the dropdowns below for a detailed description of Back Up / Down operation.
Power to Foot / Hand Control
Line voltage (115 VAC) is supplied thru two primary fuses located at the table base.
The 115 VAC is sent thru the Passive PFC board to the Motor Control PC board. The Motor Control PC board reduces the voltage to 3.3 VDC which is supplied to the foot control.
Fuse F2 on the Motor Control PC board protects the transformer on the board and the electronics supplied by the transformer.
Back Up Operation
When the Back Up function is activated, the foot control sends a command to the Motor Control PC Board. The Motor Control PC board supplies the correct voltage to the Back actuator motor.
Fuse F1 on the Motor Control PC board protects the Back actuator motor.
The actuator motor runs and raises the Back section.
The actuator motor runs until:
•Foot control button is released.
•Back Up limit switch is tripped.
•Overcurrent protection tripped.
Back Down Operation
When the Back Down function is activated, the foot control sends a command to the Motor Control PC board. The Motor Control PC board supplies the correct voltage to the Back actuator motor.
Fuse F1 on the Motor Control PC board protects the Back actuator motor.
The actuator motor runs and lowers the Back section.
The actuator motor runs until:
•Foot control button is released.
•Back Down limit switch is tripped.
•Overcurrent protection tripped.
