product button is pressed, the timing circuitry activates a coil in the basket lift relay to supply power to the motor.
There are two types of basket lifts: the “bell crank” design, and the “modular” design
A bell crank basket lift consists of a cam and bell crank that are connected to the basket lift arm by a flat metal link. The cam is attached to a drive motor. The motor rotates the cam, thus raising or lowering the lift arm linked to the bell crank. A
Left bell crank and cam with basket lift link shown in the down position. Note the microswitch in the upper right corner.
Bell Crank Basket Lift
Simplified Schematic
LEFT BASKET | RIGHT BASKET |
LIFT TIMER | LIFT TIMER |
C | C |
TM | TM |
NO | NO |
L
NC
H
N
NC | NO |
C
LEFT
MICROSWITCH
M
LEFT BASKET
LIFT MOTOR
L |
NC
NC | NO |
C
RIGHT
MICROSWITCH
M
RIGHT BASKET
LIFT MOTOR
When the timer button is pushed, the NO circuit in the timer is closed, supplying voltage through the microswitch to the motor. The bell crank/cam rotates until switch postition in the microswitch is reversed, stopping the motor with the basket in the down position. When the timer reaches zero, the the switch in the timer reverts to the NC position. This supplies power to the motor via the microswitch. Once again, rotation of the bell crank/cam eventually causes the microswitch to reverse itself, stopping the motor with the basket in the up position.